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1
McKinlay, Sarah M. "The interactions between ammonifying and nitrifying bacteria". Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338396.
Texto completo da fonteResumo:
The effects of adhesion to surfaces on the specific growth rates of Nitrosomonas europaea and Nitrobacter sp. were determined in batch culture systems both in monoculture and co-culture. It was found that the presence of a glass slide in co-cultures of these bacteria significantly reduced the specific growth rates of both species of bacteria. In monoculture, the specific growth rate of N. europaea was significantly lower in a mature biofilm system. The specific rates of production of ammonia by these four species of Pseudomonas were investigated in minimal medium. All four species converted approximately 60 - 80% of the provided L-alanine to ammonia, and this production of ammonia raised the pH of the medium. All four strains were capable of this when the initial pH of the medium was 5.5 or 7.5, however, lowering the initial pH of the medium reduced the specific rate of production of ammonia for P. cepacia, P. fluorescens and P. syringae, and reduced the final concentration of ammonia produced by P. cepacia. Ammonia produced by P. fluorescens could support the growth of N. europaea in liquid batch culture. The growth of the pseudomonad increased the pH of the medium from 5.5 to 6.8 and this increase in pH allowed growth of the nitrifier in the medium with the lower initial pH. The growth of N. europaea and P. fluorescens in continuous flow biofilm reactors was examined, and the addition of P. fluorescens to a nitrifying biofilm raised the pH of the bulk medium, thus removing the effects of pH inhibition on the ammonia oxidiser. Further investigations were carried out in continuous flow sand column systems and it was found that the rapid growth of the pseudomonad caused obstruction of the column.
2
Jones, Nicole Jean. "NITRIFYING BACTERIAL ABUNDANCE IN RELATION TO NITROGEN AND PHOSPHORUS COMPOUNDS IN WETLANDS". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/829.
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Floodplain lakes are wetlands which receive flood waters from nearby rivers or other sources. Water samples were taken from floodplain lakes near the Illinois River, the Mississippi River, and the Cache River in Southern Illinois. Fluorescence in situ hybridization (FISH), spectrophotometry, and gene probes were used to investigate the effect of nutrient and chemical concentrations on the abundance of nitrifying bacteria; specifically ammonia-oxidizing Nitrosococcus and Nitrosomonadales and nitrite-oxidizing Nitrospira and Nitrobacter. Nitrosococcus was the dominant ammonia-oxidizing bacteria at each river system. Nitrospira and Nitrobacter had similar average abundances. Nitrosococcus abundances showed a significant positive correlation with nitrate (NO3-) (R2= 0.247, P=0.05, 95% confidence R2≥0.199) and a positive trend with nitrite (NO2-) (R2= 0.194, P=0.10, 90% confidence R2≥0.125). Nitrosomonadales abundance positively correlated with temperature (R2= 0.530, P=0.05, 95% confidence R2≥0.510). Nitrospira abundances positively correlated with ammonium (NH4+) (R2= 0.265, P=0.05, 95% confidence R2≥0.199), NO2- (R2= 0.372, P=0.05, 95% confidence R2≥0.199), and NO3- (R2= 0.482, P=0.05, 95% confidence R2≥0.199). None of the target bacterial abundances significantly correlated with pH or dissolved inorganic phosphate.
3
Cheatham, Amy Kathleen. "Responses of Nitrifying Bacteria to Aquaculture Chemotherapeutic Agents". Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26879.
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As in any animal production industry, disease is inevitable; therefore, it is imperative that aquaculturists are able to effectively manage the disease and maintain their high production levels in an effort to bridge the gap between supply and demand in the seafood industry that has been caused in part by global over-fishing. This management responsibility lies not only in understanding the impact of the treatment on the cultured species, but also in understanding the impact of the treatment to the aquaculture system as an ecosystem. Currently, there is a narrow variety of chemicals approved by either the Food and Drug Administration (FDA) or the Environmental Protection Agency (EPA) for the treatment of disease outbreaks and water quality issues in aquaculture. Approved chemotherapeutants include oxytetracycline, Romet-30®, copper, and formalin. Additionally, a number of chemicals, such as Chloramine-T and potassium permanganate, are used off-label for the treatment of aquaculture systems. In this research, these six more commonly used chemotherapeutants were analyzed for their impacts to the nitrifying bacteria in aquaculture systems.
It was found that three of the chemotherapeutants: oxytetracycline, Romet-30®, and chelated copper caused inhibition to the nitrifying bacteria at the whole cell level as demonstrated in the results from water quality and specific oxygen uptake rate analyses. The nitrification process resumed once the chemotherapeutant was removed from the system, either by a mandatory water change or by natural degradation. The other three chemicals: formalin, Chloramine-T, and potassium permanganate did not result in any significant inhibition to the nitrification process. Experiments on laboratory-cultured nitrifying bacteria confirmed these findings. These experiments also resulted in the observation that the expression of amoA was upregulated by the copper exposure and inhibited by oxytetracycline and Romet-30®, but began to resume as the antibiotics degraded. Comprehensively, the findings of these analyses demonstrated that, although nitrifiers are well-known to be sensitive to their environment, the ability of nitrifying bacteria to continue their oxidative processes following exposure to chemical stress is inherent to the bacteria themselves rather than simply occurring under the protection of a biofilm community as has been suggested.Ph. D.
4
Song, Weining. "Some aspects of the utilization of inorganic nitrogen compounds and carbon compounds by "Nitrobacter hamburgensis" /". Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09A/09as724.pdf.
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5
Smith, Timothy R. "Evaluating the effectiveness of commercial nitrifying bacteria in a constructed wetland". Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1020149.
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This research was conducted to determine the effects of commercially available nitrifying bacteria in a constructed wetland. The study was conducted at Paws, Inc., near Desoto, Indiana during the summer of 1995. The wetland, called Solar Aquatics Treatment System (SAS), was developed by Ecological Engineering Associates and constructed in a, greenhouse. The commercial nitrifying bacteria (Bacta-Pur), contained Nitrosomonas and Nitrobacter Spp. and have been added to the wetland for the past five years to aid in the removal of nitrogen.Water samples were taken from the wetland and analyzed for ammonia, nitrite, nitrate, dissolved oxygen, hydrogen ion concentrations and water temperature from Monday through Friday for three weeks. A baseline was established from these samples. After three weeks of testing the addition of Bacta-Pur to the wetland was discontinued.To determine whether these additional bacteria were needed, testing without the Bacta-Pur was conducted for three weeks. These samples were collected and analyzed for the same parameters as those used to establish baseline information.Ammonia concentrations were significantly lower without the addition of Bacta-Pur bacteria. There were no significant differences for concentrations of nitrite and nitrate. The water temperature was higher in the three weeks when no Bacta-Pur was added. This was due to the increase in ambient temperature which caused the water temperature in the SAS to increase. Since the nitrogen compounds either remained the same or decreased in concentration at the effluent without the addition of bacteria, the addition of Bacta-Pur is not needed in order to remain in compliance with EPA regulations for effluent standards.A container experiment was conducted to provide an' environment that had no introduced bacteria before the addition of Bacta-Pur. There were no significant differences for the nitrogen compounds between wastewater samples with addition and without addition of Bacta-Pur bacteria.Department of Natural Resources and Environmental Management
6
Hughes, Leonie. "Multistage and multiple biomass approaches to efficient biological nitrogen removal using biofilm cultures". Thesis, Hughes, Leonie ORCID: 0000-0001-6496-988X (2008) Multistage and multiple biomass approaches to efficient biological nitrogen removal using biofilm cultures. PhD thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/674/.
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Nitrogen removal from wastewater is important for the revention of significant health and environmental impacts such as eutrophication. Nitrogen removal is achieved by the combined action of nitrification and denitrification. Nitrification is performed by autotrophic, slow growing microorganisms that require oxygen and are inhibited in the presence of denitrifiers when oxygen and COD are available due to competition for oxygen. Denitrification however, performed by relatively fast growing heterotrophic bacteria, is inhibited by oxygen and requires COD. This implies that nitrification and denitrification are mutually exclusive. The supply of oxygen to a fresh wastewater, high in ammonia and COD, causes waste of both oxygen and COD. Conservation of COD is therefore critical to efficient wastewater treatment. The approach investigated in this study to achieve complete nitrogen removal was to physically separate the nitrification and denitrification biomasses into separate bioreactors, supplying each with appropriate conditions for growth and activity.
A storage driven denitrification sequencing batch biofilm reactor (SDDR) was established which exhibited a high level of COD storage (up to 80% of influent COD) as poly-B-hydroxybutyrate capable of removing >99% of nitrogen from wastewaters with a C/N ratio of 4.7 kg COD/kg N–NO3 –. The SDDR was combined in sequential operation with a nitrification reactor to achieve complete nitrogen removal. The multiple stage, multiple biomass reactor was operated in sequence, with Phase 1 - COD storage in the storage driven denitrification biofilm; Phase 2 - ammonia oxidation in the nitrification reactor; and Phase 3 - nitrate reduction using the stored COD in the storage driven denitrification reactor. The overall rate of nitrogen removal observed was up to 1.1 mmole NH3 L–1 h–1 and >99% of nitrogen could be removed from wastewaters with a low C/N ratio of 3.9 kg COD/kg N–NH3.
The multiple stage, multiple biomass system was limited in overall nitrogen removal the reduction in pH caused by nitrification. A parallel nitrification-denitrificatio (PND) reactor was developed in response to the pH control issue. The PND reactor was operated with Phase 1 – COD storage in the storage driven denitrification biofilm and Phase 2 – simultaneous circulation of reactor liquor between the denitrification and nitrification biofilms to achieve complete nitrogen removal and transfer of protons. The PND reactor performed competitively with the multistage reactor (removal of >99% nitrogen from wastewaters with feed ratios of 3.4 kg COD/kg N–NH3) without the need for addition of buffering material to oderate the pH.
7
Hughes, Leonie. "Multistage and multiple biomass approaches to efficient biological nitrogen removal using biofilm cultures". Hughes, Leonie (2008) Multistage and multiple biomass approaches to efficient biological nitrogen removal using biofilm cultures. PhD thesis, Murdoch University, 2008. http://researchrepository.murdoch.edu.au/674/.
Texto completo da fonteResumo:
Nitrogen removal from wastewater is important for the revention of significant health and environmental impacts such as eutrophication. Nitrogen removal is achieved by the combined action of nitrification and denitrification. Nitrification is performed by autotrophic, slow growing microorganisms that require oxygen and are inhibited in the presence of denitrifiers when oxygen and COD are available due to competition for oxygen. Denitrification however, performed by relatively fast growing heterotrophic bacteria, is inhibited by oxygen and requires COD. This implies that nitrification and denitrification are mutually exclusive. The supply of oxygen to a fresh wastewater, high in ammonia and COD, causes waste of both oxygen and COD. Conservation of COD is therefore critical to efficient wastewater treatment. The approach investigated in this study to achieve complete nitrogen removal was to physically separate the nitrification and denitrification biomasses into separate bioreactors, supplying each with appropriate conditions for growth and activity.
A storage driven denitrification sequencing batch biofilm reactor (SDDR) was established which exhibited a high level of COD storage (up to 80% of influent COD) as poly-B-hydroxybutyrate capable of removing >99% of nitrogen from wastewaters with a C/N ratio of 4.7 kg COD/kg N–NO3 –. The SDDR was combined in sequential operation with a nitrification reactor to achieve complete nitrogen removal. The multiple stage, multiple biomass reactor was operated in sequence, with Phase 1 - COD storage in the storage driven denitrification biofilm; Phase 2 - ammonia oxidation in the nitrification reactor; and Phase 3 - nitrate reduction using the stored COD in the storage driven denitrification reactor. The overall rate of nitrogen removal observed was up to 1.1 mmole NH3 L–1 h–1 and >99% of nitrogen could be removed from wastewaters with a low C/N ratio of 3.9 kg COD/kg N–NH3.
The multiple stage, multiple biomass system was limited in overall nitrogen removal the reduction in pH caused by nitrification. A parallel nitrification-denitrificatio (PND) reactor was developed in response to the pH control issue. The PND reactor was operated with Phase 1 – COD storage in the storage driven denitrification biofilm and Phase 2 – simultaneous circulation of reactor liquor between the denitrification and nitrification biofilms to achieve complete nitrogen removal and transfer of protons. The PND reactor performed competitively with the multistage reactor (removal of >99% nitrogen from wastewaters with feed ratios of 3.4 kg COD/kg N–NH3) without the need for addition of buffering material to oderate the pH.
8
Ray, Anirban. "Identification, Enumeration and Diversity of Nitrifying Bacteria in the Laurentian Great Lakes". Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1351276518.
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9
Lako, Joseph. "Analysis of ammonia-oxidizing bacteria associated with the roots of Proteaceae plant species in soils of Fynbos ecosystem". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The major objective of this study was to investigate soil ammonia-oxidizing bacterial diversity and composition associated with plant roots of Proteaceae plants and to compare it with non-plant associated soil.
10
Meng, Yiyu. "Nitrite oxidising bacteria in soil : examination of the interactions with ammonia oxidisers and the influence of pH on their diversity and distribution". Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231853.
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Nitrification is a central part of the nitrogen cycle, whereby the most reduced form, ammonia, is converted to the most oxidised form, nitrate via nitrite. The first step is performed by ammonia oxidising bacteria (AOB) and archaea (AOA), with the second step performed by nitrite oxidising bacteria (NOB). Although both groups are closely associated in nature, ammonia oxidisers have received more attention compared to NOB as ammonia oxidation is considered the rate-limiting step. Nitrobacter and Nitrospira are two important groups of soil NOB. To determine whether there are specific associations of AOA or AOB with certain NOB, the effect of organic and inorganic ammonia sources was tested by adding glutamate or ammonium sulphate to soil together with either 5% 12CO2 or 13CO2 to determined autotrophic growth by DNA-SIP. The results demonstrated that while the various ammonia and nitrite oxidisers responded differently, there was no direct evidence of specific coupled interactions. The effects of soil pH on Nitrobacter and Nitrospira was then investigated in a long-term pH gradient in an agricultural field. The results demonstrated that Nitrospira abundance was lower in acidic soils, whereas Nitrobacter abundance remained equally or more abundant. pH also influenced the relative distribution of Nitrobacter and Nitrospira populations, with distinct community structures at both high and low pH. The interaction of AOA and NOB was further investigated in a co-culture experiment, and demonstrated that the removal of nitrite and free nitrous acid NOB enhanced both rates and amounts of ammonia oxidised, indicating that in acidic environments these relationships may be particularly critical. Finally, the use of the compound PTIO was investigated for potential use in elucidating specific relationships between AOA and NOB. Results demonstrated a lack of specificity for the target group, and was unstable in soil, and therefore its use in soil should proceed with caution.
11
Zaklikowski, Anna Emilia. "The Effect of Chlorine and Chloramines on the Viability and Activity of Nitrifying Bacteria". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33758.
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Nitrification is a significant concern for drinking water systems employing chloramines for secondary disinfection. Utilities have implemented a range of disinfection strategies that have varying levels of effectiveness in the prevention and control of nitrification events, including optimizing the chlorine-to-ammonia ratio, maintaining chloramine residual throughout the distribution system, controlling pH, and temporal switching to free chlorination. Annual or semi-annual application of free chlorination is practiced by 23% of chloraminating systems on a temporary basis as a preventative measure, even though it has the undesirable consequences of temporarily increasing disinfection byproducts, facilitating coliform detachment, and altering water taste and odor.
Although temporal free chlorination and other nitrification control methods have been widely studied in the field and in pilot-scale systems, very little is known about the stress responses of nitrifying bacteria to different disinfection strategies and the role physiological state plays in the resistance to disinfection. It is well known that many commonly studied bacteria, such as Escherichia coli, are able to better resist disinfection by free chlorine and chloramines under nutrient limitation through regulation of stress response genes that encode for DNA protection and enzymes that mediate reactive oxygen species. We compared the genomes of E. coli and the ammonia-oxidizing bacterium Nitrosomonas europaea, and found that many of the known stress response mechanisms and genes present in E. coli are absent in N. europaea or not controlled by the same mechanisms specific to bacterial growth state. These genetic differences present a general susceptibility of N. europaea to disinfection by chlorine compounds.
Using an experimental approach, we tested the hypothesis that N. europaea does not develop increased resistance to free chlorine and monochloramine during starvation to the same degree as E. coli. In addition, N. europaea cells were challenged with sequential treatments of monochloramine and hypochlorous acid to mimic the disinfectant switch employed by drinking water utilities. Indicators of activity (specific nitrite generation rate) and viability (LIVE/DEAD® BacLight⠢ membrane-integrity based assay) were measured to determine short-term effectiveness of disinfection and recovery of cells over a twelve day monitoring period. The results of disinfectant challenge experiments reinforce the hypothesis, indicating that the response of N. europaea to either disinfectant does not significantly change during the transition from exponential phase to stationary phase. Exponentially growing N. europaea cells showed greater susceptibility to hypochlorous acid and monochloramine than stationary phase E. coli cells, but had increased resistance compared with exponential phase E. coli cells. Following incubation with monochloramine, N. europaea showed increased sensitivity to subsequent treatment with hypochlorous acid. Complete loss of ammonia-oxidation activity was observed in cells immediately following treatment with hypochlorous acid, monochloramine, or a combination of both disinfectants. Replenishing ammonia and nutrients did not invoke recovery of cells, as detected in activity measurements during the twelve day monitoring period. The results provide evidence for the effectiveness of both free chlorine and chloramines in the inhibition of growth and ammonia-oxidation activity in N. europaea. Furthermore, comparison of viability and activity measurements suggest that the membrane integrity-based stain does not serve as a good indicator of activity. These insights into the responses of pure culture nitrifying bacteria to free chlorine and monochloramine could prove useful in designing disinfection strategies effective in the control of nitrification.
Master of Science
12
Cao, Huiluo, e 曹慧荦. "Molecular ecology of ammonia oxidizing archaea and bacteria". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47155358.
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The newly recognized ammonia-oxidizing archaea (AOA) makes re-evaluation of the contribution to ammonia oxidization by both AOA and ammonia-oxidizing bacteria (AOB) necessary and meaningful. The growing population and increasing anthropogenic activities around coastlines have affected wetland and coastal marine ecosystems through discharging polluted water containing large amounts of reactive inorganic nitrogen. The objectives of this study were to detect the phylogenetic diversity and abundance of ammonia oxidizers including AOA and AOB on different scales and to elucidate the distribution patterns along an anthropogenic pollution gradient from the coastal wetland of the Mai Po Nature Reserve in Hong Kong to the South China Sea (SCS).
Generally, besides lineages shared by similar environments, various endemic lineages were also observed in the polluted mangrove sediments of Hong Kong, and in the coastal, and deep-sea surface and subsurface sediments from the SCS indicating their geographical distance should be responsible for these phylogenetic distinctions. The community structures of AOA and AOB observed were proposed to be associated with environmental parameters including metals and total phosphorus (TP) separately in the sediments while their abundance was correlated with the pH value and temperature. On the other hand, along a profile of surface sediments with stable salinity from the coastal margin to the slope in the SCS, a clear community structure transition was detected for both AOA and AOB, showing major differences in each of their responses. Although the abundance of AOA was lower than that of AOB in the subsurface sediment samples from the SCS, the statistical support for relationships between AOA and nitrite concentration shed new light on the active contributor to the subsurface nitrogen cycle in the oxygen minimum zone from the deep-sea sediments.
On a large scale, along the anthropogenic pollution gradient from the Pearl River Delta to the coastal margin and then the SCS, the dominant genus transition from Nitrosomonas to Nitrosospira was detected in response to the salinity and anthropogenic influences. Among a wide spectrum of environmental conditions in the western Pacific, a suite of statistical analyses clearly delineated the shallow and deep-sea sediments clusters suggesting that the depth and other contributing environmental factors involved shape the current distribution pattern of AOA. On a global scale, our understanding about the systematics and evolution of AOA was advanced through phylogenetic analyses. Salinity, lifestyle and temperature were proposed to be responsible for the global distribution patterns of AOA. On the basis of studies in the anthropogenic influence areas, the methods to detect specific responses of ammonia oxidizers to known anthropogenic pollution were concluded.
Highlights of this study advance not only our understandings about phylogenetic diversity of ammonia oxidizers and the driving forces shaping their community structure and distribution patterns, but also a revised comprehensive view about them on the larger scale.published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
13
Daims, Holger. "Population structure and functional analyses by in situ techniques of nitrifying bacteria in wastewater treatment plants". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963771582.
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Morris, Raymond Anthony. "Investigation of the Optimal Dissolved CO2 Concentration and pH Combination for the Growth of Nitrifying Bacteria". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3256.
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Ammonium (NH4+) is a biological nutrient that is transformed in a wastewater treatment plant (WWTP) in a process called activated sludge. This is accomplished in an aerobic environment using microorganisms and inorganic carbon that convert the ammonium to nitrate (NO3-). This process is termed nitrification. Removal of ammonium is necessary due to its oxygen demand and toxicity to the environment.
Nitrification is considered a slow process due to the slow growth rate of the nitrifying bacteria. Ammonia oxidizing bacteria (AOB) first covert the ammonium (NH4+) to nitrite (NO2-) followed by conversion to nitrate (NO3-) by nitrite oxidizing bacteria (NOB). These slow rates limit the treatment capacity of the WWTP.
The initial hypothesis suggested that these slow rates were due to limited carbon in the aeration basin of a WWTP. A series of designed experiments and observational studies revealed substantial dissolved CO2 exists throughout a WWTP. Based on these findings, the central research focused on determining if an optimum dissolved CO2 concentration/ pH combination exists that maximizes nitrification.
Experimentation conducted at a pH of 7.0 and varying concentrations of dissolved CO2 concentration revealed inhibition at low (<5 mg/l) and high (>30 mg/l) dissolved CO2 concentration levels. Further research found that optimum nitrification can be attained in a dissolved CO2 concentration range of 10 - 15 mg/l and a pH range of 7.5 - 8.0. A maximum specific growth rate of 1.05 - 1.15 days-1 was achieved. A partitioning of the sums of squares from these designed experiments found that pH accounts for approximately 83 percent of the sums of squares due to treatment with the dissolved CO2 concentration accounting for 17 percent. This suggests that pH is the dominant factor affecting nitrification when dissolved CO2 concentration is optimized.
Analysis of the growth kinetics for two of the designed experiments was conducted. However, a set of parameters could not be found that described growth conditions for all operating conditions. Evaluating the results from these two experiments may suggest that a microbial population shift occurred between 16 and 19 mg/l of dissolved CO2 concentration. These dissolved CO2 concentrations represent pH values of 7.1 and 7.0, respectively, and were compared to experimentation conducted at a pH of 7.0. Though the pH difference is minor, in combination with the elevated dissolved CO2 concentration, a microbial shift was hypothesized.
Microbial samples were collected from the designed experiment that optimized dissolved CO2 concentration (5, 10 and 15 mg/l) and pH (6.5, 7.0, 7.5 and 8.0). These samples were evaluated using Fluorescence in situ hybridizations (FISH) to determine the population density of common ammonium oxidizing bacteria (AOB) (Nitrosomonas and Nitrosospira) and nitrite oxidizing bacteria (NOB) Nitrobacter and Nitrospirae). The dominant AOB and NOB microbes were found to be Nitrosomonas and Nitrospirae.
These results suggest that increased nitrification rates can be achieved by incorporating appropriate controls in a wastewater treatment plant (WWTP). With higher nitrification rates, lower nitrogen values can be obtained which will reduce the WWTP effluent nitrogen concentration. Conversely, these increased nitrification rates can also reduce the volume of an aeration basin given similar effluent nitrogen concentrations.
15
Repke, Rodrigo Alberto 1988. "Efeito de diferentes concentrações e estirpes da bactéria Azospirillum brasilense nos componentes de produção em plantas de trigo /". Botucatu, 2016. http://hdl.handle.net/11449/144493.
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Orientador: Silvio José BicudoCoorientador: Rogério Peres Soratto
Banca: Marcio Christian S. Domingues
Banca: Priscila Gonzales Figueiredo
Banca: Carlos Jorge da Silva
Banca: Luciano Soares de Souza
Resumo: O triticum aestivum é uma espécie de ciclo anual, pertencente à família Poaceae. Cultivado em regiões de climas subtropical e temperado, ocupa a segunda maior área plantada no mundo. Para obtenção de altas produtividade dentre outros cuidados, é essencial o fornecimento de nutrientes na quantidade demandada pelas cultivares de alto potencial produtivo, com destaque para o nitrogênio (N). A fixação biológica de nitrogênio é realizada por microrganismos simbióticos associados com raízes das plantas. Entre os microrganismos simbióticos que fixam nitrogênio associados com raízes de plantas, destacam-se os do gênero Azospirillum brasilense. O objetivo no presente trabalho foi avaliar a eficiência do uso da inoculação Azospirillum brasilense no desenvolvimento e componentes produtivos da cultura do trigo. O estudo foi dividido em dois experimentos sendo o primeiro em ambiente protegido e o segundo em ambiente não protegido, ambos na Faculdade de Ciências Agronômicas - Universidade Estadual Paulista "Júlio de Mesquita Filho", Campus de Botucatu, SP, no ano agrícola 2013. O delineamento utilizado foi o de blocos inteiramente casualizados para ambiente protegido e blocos casualizados para ambiente não protegido, com 10 tratamentos em esquema fatorial 3x3+1. Sendo os tratamentos compostos pelo uso de duas estirpes (Ab-V5 e Ab-V6) isoladamente e em combinação das mesmas (Ab-V5+Ab-V6), todos aplicados em três concentrações 65, 130 e 195 milhões de unidades formadoras de colônia (UFC) de...
Abstract: Triticum aestivum is a yearly crop species belonging to the Poaceae family. It is cultivated in regions with subtropical and temperate climate, and takes up the second largest planted area in the world. Nutrient provision in the demanded amount by high productive potential cultivars, mainly nitrogen (N), is essential to obtain high productivity. The biological fixation of nitrogen is done by symbiotic microorganisms associated with plan roots. Azospirillum brasilense is one of the genera in which the symbiotic microorganisms fixate nitrogen associated with plant roots. This study aimed to evaluate the agronomical efficiency of Azospirillum brasilense inoculation on the growth and productive components of wheat cultivation. The study was divided into two experiments: the fist protected environment, and the second non-protected environment conditions, both in the School of Agriculture - Universidade Estadual Paulista "Júlio de Mesquita Filho", Campus of Botucatu, SP, Brazil, during 2013 crop year. The experiment had completely randomized block design for the fist experiment in protected environment, and random blocks for the second experiment in non-protected environment, with 10 treatments in 3x3+1 factorial scheme. The treatments consisted of two separate (V5 and V6) and combined (V5+V6) stocks and three concentrations (65, 130 and 195 million UFC of bacteria) were applied. The control treatment had no bacterial inoculation. For the protected environment, each experimental plot consisted of plants cultivated in an asbestos recipient with the following dimensions: 0.50 m of height, 0.88 m of width and 1.05 m of length, and 0.462 m3 of soil. Seven 0.88-m rows with 0.15 m spacing and 40 seeds per meter were utilized. In the field experiment, the experimental plot consisted of ten 2.0-m rows with 0.17 m spacing and 45 seeds per meter. For both experiments, the seeding density was 266 seeds m2, aiming ...
Doutor
16
Moore, J. Michael. "Nitrification inhibition by metalaxyl as influenced by pH, temperature, and moisture content in three soils". Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54249.
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Metalaxyl, [N—(2,6-Dimethylphenyl)-N-(Methoxyacetyl)-alanine methyl ester], is used extensively in tobacco (Nicotiana tabacum L.) production for prevention of black shank (Phytophthora parasitica Dast. var. nicotianae), blue mold (Peronospora tabacina Adam), and damping-off (Pythigm spp.). Metalaxyl is also patented as a nitrification inhibitor, although not marketed for that purpose. Proper maturity and ripening of flue-cured tobacco depends on an adequate supply of N through the time of removal of the inflorescence, with a declining supply of N from that point. Use of a chemical which might prolong the availability of N in tobacco could delay maturity and reduce the quality of the cured leaf. These studies were conducted to determine whether metalaxyl might inhibit nitrification under a broad range of soil physical and environmental conditions prevalent in the tobacco producing areas of Virginia. The influence of soil type, soil pH, soil temperature, and soil moisture on inhibition of nitrification by metalaxyl (1 mg kg⁻¹) were investigated in three soils used extensively for tobacco production. Soils used in the study were Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult), Appomattox fine sandy loam (clayey, mixed, thermic Typic Kandhapludult), and Mattoponi sandy loam (clayey, mixed, thermic Typic Hapludult). Metalaxyl did not inhibit nitrification under any of the conditions studied. However, NO₂⁻ accumulation with metalaxyl was sometimes greater than the control, especially at high pH (7.0) in the Cecil and Appomattox soils, and at 10 and 20°C. Nitrite and NO₃⁻ accumulations from four rates of metalaxyl (1, 5, 25, and 125 mg kg⁻¹) were compared with those of an untreated control and a nitrapyrin standard over a seven week soil incubation period in further studies using the same soils and adjusted pH levels. Significant NO₂⁻ accumulation occurred during the first week after treatment at high pH in all soil types, with 5, 25, and 125 mg kg⁻¹ metalaxyl. Only the 125 mg kg⁻¹ metalaxyl treatment caused NO₂⁻ accumulation at the high pH in all soils beyond the second week after treatment, with the peak occurring in most cases between weeks three and four. Nitrate accumulation proceeded normally in all soil types and pH levels except with treatments of 25 and 125 mg kg". Nitrate accumulations with 25 mg kg⁻¹ were similar to those for nitrapyrin. The 125 mg kg⁻¹ rate was consistent in causing near total inhibition of NO₃⁻ accumulation at all pH levels in all soils. Nitrate accumulation tended to be lower at lower soil pH levels compared to the highest pH for all soils. Little difference in nitrification due to soil appears to be evident. Use of metalaxyl at recommended rates of 0.25 to 1.5 mg kg⁻¹ would not be expected to inhibit nitrification.Ph. D.
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Hoang, Phuong Ha, Hong Thu Nguyen, Trung Thanh Trung, Thanh Tung Tran, Lan Phuong Do e Thi Nhi Cong Le. "Isolation and selection of nitrifying bacteria with high biofilm formation for treatment of ammonium polluted aquaculture water". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227866.
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A biofilm is any group of microorganisms in which cells stick to each other and adhere to a surface by excreting a matrix of extracellular polymeric substances (EPS). The chemoautotrophic nitrifying bacteria hardly form biofilms due to their extremely low growth rate; however, biofilm formation of nitrifying bacteria trends to attach in carrier by extracellular polysaccharides that facilitate mutual adhesion, the forming biofilm is also beneficial in nitrogen removal in biological filter systems, especially in aquaculture water treatment systems. The microbial activity within bio-carrier is a key factor in the performance of biofilm reactor. Selection the nitrifier bacteria that biofilm formation and immobilization on the carrier for application in ammonium polluted water treatment technologies, especially in aquaculture is our research objective. Therefore, in this study, ten and six strains of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) respectively were isolated from six different aquaculture water samples collected from Quang Ninh and Soc Trang. Basing on their high nitrification activity and biofilm forming capacity, six bacterial strains have been selected to take photo by scanning electron microscope (SEM) and carry out in 2 – liter tanks with and without carriers. As the results, the system with carriers (30% of total volume) increased nitrogen compounds elimination efficiency from 1.2 times to 2 times in comparison with the system without carrier. Two representatives of ammonia oxidizing bacterial group (B1.1; G2-1.2) were classification based on characteristics and they were classified as Nitrosomonas sp. and Nitrosococcus spMàng sinh học được hình thành từ vi sinh vật nhờ các tế bào tiết ra các chất cao phân tử ngoại bào (EPS) và dính vào nhau đồng thời được gắn lên một bề mặt vật thể lỏng hoặc rắn. Vi khuẩn nitrate hóa tự dưỡng có thể tạo ra màng sinh học nhưng khá khó khăn do tỷ lệ sinh trưởng rất chậm của chúng. Tuy nhiên vi khuẩn nitrate hóa tạo màng sinh học thường có xu thế bám lên giá thể nhờ sự gắn kết của các polisaccarit ngoại bào. Sự hình thành màng sinh học cũng là lợi thế để loại bỏ các hợp chất nitơ trong các hệ thống lọc sinh học, đặc biệt là trong các hệ thống xử lý nước nuôi trồng thủy sản. Hoạt tính vi sinh vật cùng với giá thể sinh học là một yếu tố quan trọng để thực hiện trong các bể phản ứng màng sinh học. Trong nghiên cứu này, mục tiêu của chúng tôi là lựa chọn được các vi khuẩn nitrate hóa có khả năng tạo màng sinh học và cố định chúng lên giá thể để ứng dụng trong các công nghệ xử lý nước bị ô nhiễm ammonia đặc biệt là trong nuôi trồng thủy sản. Kết quả cho thấy, từ sáu mẫu nước nuôi trồng thủy sản khác nhau từ Quảng Ninh và Sóc Trăng, 10 chủng vi khuẩn oxy hóa ammonia (AOB) và 6 chủng vi khuẩn oxy hóa nitrite (NOB) đã được phân lập. Dựa vào hoạt tính nitrate hóa và khả năng tạo màng sinh học của các chủng vi khuẩn phân lập được 6 chủng điển hình đã được lựa chọn để chụp ảnh kính hiển vi điện tử quét và được ứng dụng trong hai bể sinh học với dung tích 2 lít có chứa và không chứa chất mang (giá thể). Sau 7 ngày, hệ thống sinh học chứa giá thể (chiếm 30% thể tích) có hiệu suất loại bỏ các hợp chất nitơ tăng hơn từ 1,2 đến 2 lần so với bể sinh học không chứa chất mang. Hai đại diện của nhóm vi khuẩn oxy hóa ammonia (B-1.1 và G2-1.2) đã được phân loại sơ bộ dựa vào một số đặc điểm sinh học và chúng đã được xác định thuộc chi Nitrosomonas và chi Nitrosococcus
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Shishido, Masahiro 1960. "Effectiveness of dominant Rhizobium meliloti indigenous to Arizona soil". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276929.
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A total of 200 Rhizobium meliloti isolates were sampled from alfalfa (Medicago sativa L.) nodules in five uninoculated fields throughout Arizona. Dominant strains (≥ 20% nodule occupancy at each site) were identified using plasmid profile analysis and intrinsic antibiotic resistance patterns. The major dominant strains and a commercial strain (102F77b) were evaluated for their N fixing effectiveness in a Leonard jar study. All strains were highly effective, and no significant differences were found (p ≥ 0.05) in shoot weight, root weight, nodule weight, acetylene reduction and total N content among the strain treatments. These effective dominant R. meliloti strains indigenous to Arizona soil probably contribute to the state's high alfalfa yield. Furthermore, indigenous strains AZTCYJ, AZSC, and AZY have potential as inoculants for arid lands due to their high effectiveness and unique resistances to extreme abiotic stresses present in arid land soils.
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Nyberg, Karin. "Impact of organic waste residues on structure and function of soil bacterial communities : with emphasis on ammonia oxidizing bacteria /". Uppsala : Dept. of Microbiology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200620.pdf.
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Keuter, Sabine [Verfasser], e Eva [Akademischer Betreuer] Spieck. "Characterization of nitrifying bacteria in marine recirculation aquaculture systems with regard to process optimization / Sabine Keuter. Betreuer: Eva Spieck". Hamburg : Staats- und Universitätsbibliothek Hamburg, 2012. http://d-nb.info/1022196472/34.
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Correa, Camila Zoe. "Reator de leito estruturado com recirculação submetido à aeração intermitente no tratamento de esgoto sanitário". Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1680.
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O lançamento de compostos nitrogenados em corpos d’água pode resultar em problemas ambientais, sendo assim tratar águas residuárias, como o esgoto sanitário com o objetivo de remover não apenas matéria orgânica, mas tambémnitrogênio tem sido objeto de estudo há algumas décadas. O objetivo deste trabalho foi avaliar o desempenho de um reator de leito estruturado e fluxo contínuo, com recirculação, na remoção de matéria orgânica e nitrogênio presente em esgoto sanitário, sob diferentes ciclos de Aeração intermitente (AI) e avaliar a influência destes ciclos no desenvolvimento de bactérias nitrificantes (Bactérias Oxidadoras de Amônia – BOA e Bactérias Oxidadoras de Nitrito – BON) e desnitrificantes (DESN) aderidas (Material Suporte - MS) e em suspensão (Efluente – EF e Lodo – LD). O reator utilizado possuía volume útil de 9,4 L. Como material suporte (MS) foi utilizado espuma de poliuretano, cortada e fixada em hastes de PVC. Foram trabalhadas 3 fases de aeração (AE) e não aeração (AN) com diferentes tempos: Fase 1 (4 h AE/ 2 h AN); Fase 2 (2 h AE/ 1 h AN) e Fase 3 (2 h AE/ 2 h AN). Durante todas as fases o tempo de detenção hidráulico foi mantido em 16 h e o efluente recirculado a uma vazão de 3 vezes a vazão afluente. Foram analisados: pH, alcalinidade total, temperatura, Demanda Química de Oxigênio (DQO), Demanda Bioquímica de Oxigênio (DBO), Nitrogênio Kjeldhl Total (NKT), N-amoniacal – N-NH4+, nitrito- N-NO2 e nitrato- N-NO3. A concentração das BOA, BON e DESN foi determinada utilizando o Número Mais Provável.gSSV-1 (NMP.gSSVmL-1). Na Fase 1 o percentual de remoção de NKT, N-NH4+ e NT foi de 76±10%, 70±21% e 67±10% respectivamente. Na Fase 2 de 80±15% de remoção de NKT, 86±15% de N-NH4+ e 68±9% de remoção de NT e na Fase 3 de 58±20%, 72±28% e 41±6% de NKT, N-NH4+ e NT, respectivamente. A eficiência de desnitrificação nas 3 fases foi acima de 70%, indicando que no reator ocorreu o processo de Nitrificação e desnitrificação Simultânea (NDS). Os percentuais de remoção de DQOT foram de 88%±4 na Fase 1, 94%±7 na Fase 2 e 90%±11 na Fase 3. A ANOVA multivariada aplicada ao NMP.gSSV-1, indicou que houve diferença significativa (F: 20,2; p-valor <0,01) entre a concentração dos organismos analisados nos diferentes ciclos de AI. Porém as diferenças entre os NMP.gSSV-1 não depende apenas de fatores isolados e sim de quais meios, fases e grupos estão sendo analisados. Dos resultados conclui-se que o sistema foi eficiente em termos de remoção de nitrogênio e matéria orgânica, e que a fase que apresentou a maior disponibilidade de Oxigênio Dissolvido (OD) e relação C/N (Fase 2), foi a que obteve as menores concentrações efluentes de matéria orgânica e N-NH4+. Apontasse que houve diferença significativa entre a concentração (NMP.gSSV-1) dos organismos analisados (BOA, BON e DESN), porém esta diferença não depende de fatores isolados e sim de quais meios (MS, EF ou LD, fases (1, 2 ou 3) e grupos (BOA, BON e DESN) está sendo considerado.The release of nitrogen compounds in water bodies can result in many environmental problems, so treat wastewater, such as sewage in order to remove not only organic matter but also nitrogen has been studied a few decades. From the above, the objective of this study was to evaluate the performance of a structured bed reactor, continuous flow, with recirculation, in removing organic matter and nitrogen present in wastewater under different cycles of intermittent aeration (AI) and to evaluate the influence of these cycles in the development of nitrifying bacteria (Oxidizing Bacteria Ammonia - BOA and Bacteria Oxidizing Nitrite - BON) and denitrifying (DESN) adhered (Support Material - MS) and suspension (Effluent - EF and sludge - LD). The reactor used has usable volume of 9.4 L. As support materials (MS) polyurethane foam was used, cut and fixed in PVC rods. 3 were worked aeration phases (AE) and non-aeration (AN) at different stage: Stage 1 (4 h EA / AN 2H); Stage 2 (2H EA / AN 1 h) and Phase 3 (2H EA / AN 2 h). During all hydraulic detention time phases was kept at 16 h and the effluent recirculated at a rate of 3 times the inflow. Were analyzed: pH, total alkalinity, temperature, chemical oxygen demand (COD), Biochemical Oxygen Demand (BOD), nitrogen Kjeldhl Total (NKT), ammonia-N-N-NH4+, nitrito-N-NO2+andnitrato-NO3-. The concentration of BOA, BON and DESN was determined using the number More Provável.gSSV-1 (NMP.gSSV-1). In phase 1 the percentage removal NTK N-NH4+ and NT was 76±10%, 70±21% and 67±10% respectively. In Phase 2 80±15% of removel NKT, 86±15% of N-NH4+ e 68±9% of removel NT e na Fase 3 de 58±20%, 72±28% and 41±6% of NKT, N-NH4+ of NT, respectively. The denitrification efficiency in stage 3 was over 70%, indicating that occurred in the reactor the process of simultaneous nitrification and denitrification (NDS). DQOT the removal percentages were 88 ± 4% in Phase 1, 94 ± 7 in Phase 2 and 90± 11% in Phase 3. The multivariate ANOVA applied to NMP.gSSV-1, it indicated that there was significant (F: 20,2, p <0,01) between the analyzed concentration of organisms AI in different cycles, but the differences between NMP.gSSV-1 depends not only isolated factors but of which means, and phase groups being analysis. From the results it is concluded that the working system is efficient in terms of nitrogen removal and organic matter, and that the stage with the highest availability of Dissolved Oxygen (DO) and C/N ratio (Step 2), was the one obtained the lower concentrations of organic matter effluents and N-NH4+. Hinted that there was a significant difference between the concentration (NMP.100mL-1) of the analyzed organizations (BOA, BON and DESN), but this difference does not depend on factors alone but of which means (MS, EF or LD), stages (1, 2 or 3) and groups (BOA, BON and DESN) is being considered.
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Posso-Blandon, Lina. "Stimulation of nitrification by carbon dioxide in lab-scale activated sludge reactors". [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001285.
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Zhan, Weixi. "The fate of dosed copper to inhibit nitrification in chloraminated water distribution system". Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/1359.
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Chloramine as a secondary disinfectant has been widely used by many water utilities around the world especially in a distribution system requiring a longer retention time such as the 600km long Goldfield water distribution system of Western Australia. Chloramine is selected mainly due to its better stability and low by-products over other disinfectants. However, it is reported that under nitrifying conditions, chloramine residual could drop dramatically. Consequently the required disinfectant concentration can not be maintained. Nitrification, microbial process, is known to be causing rapid depletion of the chloramine residual and enhancing the growth of heterotrophic bacteria. In preliminary studies conducted in Water Corporation, copper at concentrations of 0.25mg/L has been found to be effective against nitrifiers. A concentration of 0.25mg/L as copper is achieved by directly dosing into the main pipeline at the outlet of the Cunderdin reservoir. Nonetheless, the preferred copper concentration can not be maintained as gradual decrease of dissolved copper in bulk water has been encountered along the pipeline.This research aimed to investigate fate of copper in bulk water and distribution system. Three fundamental mechanisms leading to copper loss had been investigated: gravitational sedimentation, adsorption onto wall or biofilm and mineral ions induced aggregation. During investigation of these mechanisms, potential controlling factors (pH, alkalinity, DOC, mineral ions…etc) were brought into a series of experiments as variables. Hardly can free cupric ions or copper hydroxide particles exist in bulk water samples. It was found that major Cu-containing forms are inorganic and organic copper compounds. Solubility of inorganic copper compounds is in equilibrium with calcium carbonate buffered system while organic copper compounds are controlled by organic matters and dissolved organic carbon in drinking water. Minerals such as ferric/ferrous ions and calcium ions contained in the distribution system can aggregate various copper species in bulk water to form particles.Consequently, it can lead to sedimentation or deposition onto walls or sediments. Wall adsorption had been simulated using glass fibre (GF) filters in the laboratory. GF filters were found able to absorb various forms of dissolved copper and copper compounds, though further work needs to be done to investigate the real pipe surface adsorption and complete the adsorption model. Historical data from the field had been analysed. Combined with laboratory results, it shows that both adsorption and mineral ions induced aggregation are contributing to the loss of copper in the distribution system. However, to further quantify these two mechanisms respectively and build up a comprehensive model, more field data are needed and more laboratory work needs to be done. Copper with different forms will be brought into inhibition experiments in the next stage of research in order to find effective form(s) against nitrifying bacteria. Based on the current achievement on the fate of copper, an inhibition strategy is suggested at the end of this thesis.
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Huang, Ying-Sheng. "Evidence for Multiple Functions of a Medicago Truncatula Transporter". Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc699903/.
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Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed in Mtnip-1/latd mutant plants, it is possible that MtNPF1.7/NIP/LATD could have similar activity as AtNPF6.3/NRT1.1(CHL1). Experimental evidence shows that the MtNPF1.7/NIP/LATD gene is able to restore nitrate-absent responsiveness defects of the Atchl1-5 mutant. The constitutive expression of MtNPF1.7/NIP/LATD gene was able to partially, but not fully restore the wild-type phenotype in the Atchl1-5 mutant line in response to auxin and cytokinin. The constitutive expression of MtNPF1.7/NIP/LATD gene affects the lateral root density of wild-type Col-0 plants differently in response to IAA in the presence of high (1mM) or low (0.1 mM) nitrate. MtNPF1.7/NIP/LATD gene expression is not regulated by nitrate at the concentrations tested and MtNPF1.7/NIP/LATD does not regulate the nitrate-responsive MtNRT2.1 gene. Mtnip-1 plants have an abnormal gravitropic root response implicating an auxin defect. Together with these results, MtNPF1.7/NIP/LATD is associated with nitrate and auxin; however, it does not act in a homologous fashion as AtNPF6.3/NRT1.1(CHL1) does in A. thaliana.
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Scudeletti, Daniele 1990. "Modos de inoculação de azospirillum brasilense em cana-de-açúcar /". Botucatu, 2016. http://hdl.handle.net/11449/146731.
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Orientador: Carlos Alexandre Costa CrusciolCoorientador: Marcelo de Almeida Silva
Banca: Gabriela Ferraz Siqueira
Banca: Eduardo Negrisoli
Resumo: A cana-de-açúcar (Saccharum spp.) é uma cultura de grande importância econômica para o Brasil, pois além de gerar empregos em setores como agrícola, industriais e terceiros, a cultura também proporciona a produção de biomassa energética. Há muitas evidências de que esta cultura seja beneficiada pela interação com bactérias diazotróficas, principalmente as do gênero Azospirillum que, além da fixação de N atmosférico podem produzir fitormônios que promovem, na maioria dos casos, efeitos positivos no crescimento vegetal, no rendimento e nas alterações fisiológicas da planta. A principal barreira à utilização do Azospirillumn a cultura da cana-de-açúcar tem sido a incon¬sistência dos resultados de pesquisa, que podem variar de acordo com a cultivar, as condições eda¬foclimáticas e a metodologia de condução da pes¬quisa. Objetivou-se, mediante o presente estudo, avaliar a eficácia dos modos de inoculação de Azospirillum brasilense, nos parâmetros biométricos, fisiológicos e tecnológicos, e as possíveis melhorias na absorção de nutrientes do solo e na produtividade. O trabalho foi desenvolvido em área experimental pertencente à Usina da Barra, localizada no município de Santa Maria da Serra - SP, na safra 2015/2016. O delineamento experimental foi em blocos ao acaso, em esquema fatorial 2 x 2, com 4 repetições. Os tratamentos foram constituídos por inoculação do Azospirillum brasilense (sem e com) e pelos modos de aplicação (tolete e foliar). Foi considerada como área útil as 4 ...
Abstract: The sugarcane (Saccharum spp.) is a crop of great economic importance to Brazil, as well as create jobs in several sectors such as agricultural, industrial and third culture also provides the production of energy biomass. There are many evidences that this crop culture is benefited by interaction with diazotrophs, especially the Azospirillum genus that in addition to atmospheric N fixation can produce phytohormones that promote, in most cases, positive effects on plant growth, yield and amendments physiological plant. The main barrier to the use of Azospirillum in sugarcane has been the inconsistency of search results, which may vary according to the cultivar, the climatic conditions and methodology of research. The aim, through this study, was to evaluate the effectiveness of Azospirillum brasilense inoculation modes, the biometric, physiological and technological parameters, and possible improvements in the uptake of soil nutrients and yield. The study was conducted in the experimental area of Sugar mill Barra, localized in Santa Maria da Serra - SP, in 2015/2016. The experimental design was a randomized block in factorial 2 x 2, with four repetitions. The treatments consisted of inoculation of Azospirillum brasilense (with and without) and the application modes (stem and leaf). It was considered useble area of the center lines 4 of 8 lines planted. The inoculation was performed by applying 2 L-1 ha of the commercial product. The inoculation of the stems was performed before covering the plating furrows and in plots that received foliar it occurred at tillering stage. It was concluded that inoculation with Azospirillum brasilense did not affect the macronutrient content, leaf chlorophyll content, stalk number, internode number and the technological quality of sugarcane and there was an increase in stalk height due to the increase in average length internode, resulting in higher yield in ...
Mestre
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Al-Hadhrami, Mohamed N. (Mohamed Nasser). "Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields". Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc501189/.
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Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter population in the soil increased the degradation rate of phenolic acids proportionally. It is proposed that seed inoculation will introduce selected strains of Azotobacter into the soil. The presence of Azotobacter should increase crop size in subsequent plantings.
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Chauret, Christian. "Effect of tungsten on nitrate and nitrite reductases in Azospirillum brasilense SP 7". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59635.
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Azospirillum brasilense reduced nitrate in W-containing Mo-limited medium, but at lower rates than in W-free medium. However nitrate reduction by Paracoccus denitrificans was completely suppressed under the same conditions. Nitrite reductase activity of growing A. brasilense was negatively affected by tungstate. Nitrite accumulation was shown to be the result of an inhibitory effect of nitrate on nitrite reductase activity. Both resting whole cell and cell-free extract preformed nitrite reductase activities were equally affected by increasing levels of tungstate. Preformed nitrate reductase activity of the cell-free extract was shown to be more sensitive to increasing concentrations of tungstate than whole cell activity, suggesting that the cytoplasmic membrane served as a protective barrier against tungsten inactivation of nitrate reductase.
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Miller, Jerry Lee 1960. "Desorption and biodegradation experiments: 1) Effect of application solvents on nitrifying bacteria, 2) Effect of surfactants on release and biodegradation of strongly bound soil residues of atrazine and naphthalene". Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/565576.
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Giracca, Ecila Maria Nunes. "Efeito do calcário em atributos biológicos do solo". Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/5460.
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The soil is a complex system composed by live organisms, organic matter, gases, water and minerals parts that interact. In this sense, the soil organisms, besides inhabitants, are part of its composition. In the soil, the agricultural activity normally begin in a natural area, with several species of plants and animals living in equilibrium, may pass to a reduction of biodiversity, in function of agricultural practices. The present study was carried out in phases, aiming to evaluate and characterize the faunal composition, the population of nitrifying bacteria, and to develop a protocol to extract earthworms DNA. The faunal composition and nitrifying bacteria, population was done in an experiment with five years of no-till with the following treatments: a) witness (without lime); b) amount indicated by SMP method to pH 6.0 (100%), incorporated to soil in 20 cm depth; c) amount indicated by SMP method to pH 6.0 (100%), distributed in soil surface; d) half of the amount indicated by SMP method to pH 6.0 (50%), distributed in soil surface; and e) one quart of the amount indicated by SMP method to pH 6.0 (25%), distributed in soil surface. To evaluate the population of soil meso and macrofauna were collected samples in July (winter) and December (summer) of 2001. For epiedafic meso and macro organisms were installed traps for capture, and for euedafic macro organisms, were collected soil monoliths. The samples collected individually were placed in plastic bags, packed in thermo boxes and taken to Soil Biology Laboratory of UFSM Soils Department. Later, were performed separation, counting and classification of taxonomic groups in level of classes and order of the organisms? Were utilized the Shanon Diversity Index (H) to evaluate the population among the treatments and theTukey test (P=0.05) to compare the means of population in the different doses and mode of lime application. The doses and mode of lime application in no-till after 5 years were not a significant factor to affect the abundance and richness of soil fauna. The most representative population of organisms was Collembola. The quantitative determination of bacteria nitrifying population was performed with seeding of dispersed soil over a layer of silica gel and later addition of a mix composed of lime, alkaline silicates and an acid mixture, that became neutral forming a second layer of silica gel that contains the nutrients specific to the growth of the bacteria group studied. The experiment was performed in triplicates with 25 mg of soil samples per plaque. After 10 days of incubation in 28-30oC were done observations and counting of the colonies developed in each plaque, presuming that each bacteria formed one colony. The counting was done every 5 days for a period of 60 days. The application of 100% lime, incorporated or on soil surface, and 50% of lime on soil surface did not were significantly different in the number of colonies of nitrifying bacteria. The pH under 4.3 in the treatments witness and 25% of lime on soil surface affected negatively the bacteria population in depths 0-5 and 5-10 cm. To develop a protocol to extract DNA of earthworms, earthworms were collected in the experiment of doses and mode of lime application in the no-till system, in the experimental area of UFSM Soils Department. After visual characterization of identical groups, 10 individuals of each specie of Eisenia foetida and Pheretima spp were placed in alcohol 70% for later characterization after morphological patterns of each specie. Other 10 individuals were open and taken all materials from its interior. Before DNA extraction, the material stayed in sterilized water for 24 hours in refrigerator to eliminate any substances that may be stayed glued to the material. Later, the material was macerated and the DNA extracted. The DNA extracted was visualized in agarose gel 1.2%. The protocol developed was efficient to extract the DNA of Eisenia foetida and Pheretima spp.O solo é um sistema complexo composto de seres vivos, ar, água, matéria orgânica e minerais que interagem. Neste sentido os organismos do solo, além de habitantes, são parte integrante de sua composição. No solo, a atividade agrícola que geralmente inicia como área natural, com muitas espécies de plantas e animais convivendo em equilíbrio, pode passar a uma redução da biodiversidade, decorrentes das práticas culturais. O presente estudo foi realizado em três etapas visando avaliar e caracterizar a composição faunística, a população de bactérias nitrificadoras e desenvolver um protocolo de extração de DNA para oligoquetas. A avaliação faunística e da população de bactérias nitrificadoras foi realizada em um experimento com cinco anos de plantio direto com os seguintes tratamentos: A) testemunha (sem calcário); B) quantidade recomendada pelo método SMP para pH 6,0 (100%), incorporada ao solo na profundidade de 20 cm; C) quantidade recomendada pelo método SMP para pH 6,0 (100%), distribuída na superfície do solo; D) metade da quantidade recomendada pelo método SMP para pH 6,0 (50%), distribuída na superfície do solo; E) um quarto da quantidade recomendada pelo método SMP para pH 6,0 (25%), distribuída na superfície do solo. Para avaliação da população da meso e macrofauna, foram coletadas amostras em julho (inverno) e dezembro (verão) de 2001. Para meso e macro organismos epiedáficos foram instaladas armadilhas de captura, e para macrorganismos euedáficos foram coletados monólitos de solos. As amostras coletadas foram, acondicionadas em caixas de isopor e levadas ao Laboratório de Biologia do Solo do Departamento de Solos da UFSM. Posteriormente, foi realizada a separação, contagem e classificação de grupos taxonômicos em nível de classe e ordem. Utilizou-se o índice de diversidade de Shannon (H) para avaliação das populações e para comparação, as médias nos diferentes tratamentos entre as doses e modos e aplicação de calcário através do teste Tukey a 5%. As doses e modo de aplicação de calcário em sistema de plantio direto após 5 anos foram fatores menos determinantes do que as condições climáticas (inverno-verão) na abundância e riqueza da fauna edáfica. A população de organismo mais representativa foi de colembola. A determinação quantitativa de população de bactérias nitrificadoras foi através da semeadura do solo dispersado sobre uma camada de sílica gel e posterior adição de uma mistura composta por calcário, silicatos alcalinos e uma mistura ácida, que contem os nutrientes específicos para o desenvolvimento do grupo bacteriano em estudo. O experimento foi realizado em plaqueamento triplicado com 25 mg de amostra de solo por placa. Após 10 dias de incubação a 28-30o C foram realizadas observações e contagens das colônias desenvolvidas nas placas, realizadas a cada 5 dias por um período de 60 dias. As aplicações de calcário 100% na superfície, 100% incorporada e 50% na superfície não diferiram significativamente no número de colônias de bactérias nitrificadoras. O pH inferior a 4,3 nos tratamentos 0% e 25% de calcário na superfície diminuiu a população de bactérias nitrificadoras. As oligoquetas, para o trabalho de desenvolvimento de um protocolo de extração de DNA, foram coletadas no experimento citado acima. Após caracterização visual de grupos idênticos, 10 indivíduos de cada espécie de Eisenia foetida e Pheretima sp. foram caracterizadas segundo padrões morfológicos. Outros 10 indivíduos foram abertos e retirado todo o material existente no seu interior. Posteriormente o material foi submetido à maceração e extração do DNA. O DNA extraído foi visualizado em gel de agarose 1,2%. O protocolo desenvolvido foi eficiente para extração de DNA em Eisenia foetida e Pheretima sp.
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Pauletti, Carla Maria. "Avaliação de bactérias nitrificantes em lodos ativados de quatro estações de tratamento de diferentes efluentes industriais". reponame:Repositório Institucional da UCS, 2016. https://repositorio.ucs.br/handle/11338/1387.
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Os sistemas de lodos ativados se destacam pelo fato de oferecerem a possibilidade de remoção satisfatória de nutrientes como nitrogênio e fósforo, com poucos requisitos de área. Para aperfeiçoar esse processo de remoção, o sistema pode ser otimizado a fim de alcançar satisfatórias condições de pH, temperatura, aeração, entre outros. As bactérias presentes no lodo ativado são capazes de transformar e remover o nitrogênio através dos processos de nitrificação e desnitrificação. As reações de nitrificação são catalisadas por diferentes gêneros de bactérias autotróficas, entres os quais Nitrosomonas, Nitrobacter, Nitrospira, Nitrococcus. Existem evidências mais recentes de que estas reações de nitrificação podem, em certa medida, também ser catalisadas por organismos heterotróficos. Assim, a identificação das bactérias presentes em lodos ativados de Estações de Tratamento de Efluentes (ETE), bem como o estudo dos fatores que podem ou não influenciar na eficiência do processo de remoção de nutrientes, é muito importante para a otimização do sistema. As análises físico-químicas e, posterior, análises da composição bacteriana foram realizadas em amostras de afluente, efluente e de lodo de quatro diferentes estações de tratamento. As coletas foram realizadas em ETE de dois abatedouros de aves, de uma indústria de embalagens de papel e de um hospital particular. As amostras analisadas mostraram resultados pouco similares entre si, evidenciando diferenças nos processos de nitrificação e desnitrificação conforme a ETE de origem. Os resultados encontrados para as análises físico-químicas nas amostras estudadas estiveram de acordo com os parâmetros normalmente encontrados para efluentes industriais e de acordo com os exigidos pela legislação (CONAMA, 2011), com exceção de apenas uma amostra (hospital), que teve um valor de nitrogênio amoniacal (21,23 mg/L) na saída do sistema acima do valor máximo permitido pela legislação vigente (20 mg/L). A eficiência de remoção de DQO em todas as estações de tratamento esteve na faixa entre 67,5% e 97,8%. A amostra da ETE da Indústria de Embalagens de Papel foi a que demonstrou maior eficiência de remoção de DQO (97,8%), enquanto que uma das amostras da ETE do Hospital Particular, que apresentou a maior DQO na entrada do sistema, foi a que obteve menor eficiência de remoção (67,5%). A remoção de nitrogênio amoniacal foi observada, com exceção de uma amostra, em todas as demais, e sua eficiência de remoção foi bastante variável nas amostras, com valores considerados satisfatórios para o parâmetro estudado (99,7%) e abaixo do esperado para sistemas de lodos ativados (24,6%). A menor eficiência de remoção de nitrogênio amoniacal (24,6%) foi encontrada para uma amostra da ETE Hospital, enquanto a maior eficiência se observou para a amostra da ETE Embalagens de Papel (99,7%). As amostras de lodo foram analisadas molecularmente através de nested PCR e DGGE, com posterior sequenciamento genético. Os primers utilizados na técnica de nested PCR foram: 11f e 1492r (primers universais), NIT3r (Nitrobacter), Nos1225r (Bactérias oxidadoras de amônio), Ntspa685r (Nitrospira), sendo o primer Eub338f utilizado em conjunto com os primers específicos. Já o PCR realizado para o DGGE foi realizado utilizando-se os primers 968F GC e 1392r. As análises moleculares demonstraram que as bactérias mais comuns nos processos de tratamento por lodos ativados (Bactérias oxidadoras de amônio, nitrobacter e nitrospira) estiveram presentes (pelo menos um dos gêneros) em quase todas as amostras testadas por PCR. A amostra que mostrou maior eficiência de remoção de DQO e nitrogênio amoniacal teve, também, resultado positivo para todos os primers utilizados (Bactérias oxidadoras de amônio, nitrobacter e nitrospira) na técnica de PCR, sugerindo que o processo de nitrificação foi satisfatório. Das amostras que tiveram resultado positivo para as amplificações com primers específicos para nitrificantes, apenas uma teve correspondência de resultado positivo no sequenciamento genético (Bactérias oxidadoras de amônio).Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2016-11-23T17:48:34Z No. of bitstreams: 1 Dissertacao Carla Maria Pauletti.pdf: 2032023 bytes, checksum: 05c1e6ec8f9dadc338303f4fd9581a5d (MD5)
Made available in DSpace on 2016-11-23T17:48:34Z (GMT). No. of bitstreams: 1 Dissertacao Carla Maria Pauletti.pdf: 2032023 bytes, checksum: 05c1e6ec8f9dadc338303f4fd9581a5d (MD5) Previous issue date: 2016-11-23
PETROBRAS, Brasil.
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Charoenpong, Chawalit(Chawalit Net). "The production and fate of nitrogen species in deep-sea hydrothermal environments". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122322.
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Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2019Cataloged from PDF version of thesis.
Includes bibliographical references.
Nitrogen (N) species in hydrothermal vent fluids serve as both a nutrient and energy source for the chemosynthetic ecosystems surrounding deep-sea vents. While numerous pathways have been identified in which N-species can be produced and consumed in the context of submarine hydrothermal vent systems, their exact nature has been largely limited to interpretation of variations in concentrations. This thesis applies stable isotope approaches to further constrain the sources and fate of N-species in deep-sea vents across a variety of geological settings. First, I discuss isotope fractionation and reaction kinetics during abiotic reduction of nitrate (NO₃⁻) to ammonium ([sigma]NH₄⁺ = NH₃+NH₄⁺) under hydrothermal conditions. Results of lab experiments conducted at high temperatures and pressures revealed a wide degree of N isotope fractionation as affected by temperature, fluid/rock ratio, and pH-all which exert control over reaction rates.
Moreover, a clear pattern in terms of reaction products can be discerned with the reaction producing [sigma]NH₄⁺ only at high pH, but both [sigma]NH₄⁺ and N₂ at low pH. This challenges previous assumptions that NO₃⁻ is always quantitatively converted to NH₄⁺ during submarine hydrothermal circulation. Next, I report measurements of [sigma]NH₄⁺ concentrations and N isotopic composition ([delta]¹⁵N[subscript NH4]) from vent fluid samples, together with the largest compilation to date of these measurements made from other studies of deep-sea vent systems for comparison. The importance of different processes at sediment-influenced and unsedimented systems are discussed with a focus on how they ultimately yield observed vent [sigma]NH₄⁺ values.
Notable findings include the role that phase separation might play under some conditions and a description of how an unsedimented site from Mid-Cayman Rise with unexpectedly high NH4+ may be uniquely influenced by N₂ reduction to [sigma]NH₄⁺. Lastly, I explore [sigma]NH₄⁺ dynamics in the context of low-temperature vent sites at 9°50'N East Pacific Rise to investigate dynamics of microbially-mediated N transformations. Through both measurements of natural samples, as well as isotopic characterization of N species from incubation experiments and model simulations thereof, an exceptionally high variability observed in [delta]¹⁵N[subscript NH4] values emphasizes the complexity of these microbe-rich systems.
In sum, this thesis highlights the role of microbial processes in low temperature systems, demonstrates a more mechanistic understanding of lesser-understood abiotic N reactions and improves the coverage of available data on deep-sea vent [sigma]NH₄⁺ measurements.
by Chawalit "Net" Charoenpong.
Ph. D.
Ph.D. Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)
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Bäckman, Jenny. "Nitrification and nitrifying bacterial communities in coniferous forest soils : effects of liming and clear-cutting /". Linköping : Univ, 2003. http://www.bibl.liu.se/liupubl/disp/disp2002/tek809s.pdf.
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Ruiz, Rueda Olaya. "Nitrifying and denitrifying bacterial communities in the sediment and rhizosphere of a free water surface constructed wetland". Doctoral thesis, Universitat de Girona, 2008. http://hdl.handle.net/10803/7871.
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La contínua descàrrega de nutrients, sobretot fosfats i nitrogen, és la major causa d'eutrofització dels ecosistemes aquàtics. Els sistemes de tractament basats en aiguamolls construïts s'han emprat per reduir ells nivells de nitrogen a l'aigua com a alternativa de baix cost als mètodes de depuració convencionals. L'eliminació del nitrogen a aquests sistemes depèn en bona part de la vegetació, i l'alternança de condicions aeròbiques i anaeròbiques per promoure els processos de nitrificació i desnitrificació. En aquest treball hem volgut investigar les activitats microbianes de nitrificació i desnitrificació en relació a dues espècies de plantes macròfites en un sistema d'aiguamolls de tractament de flux superficial (FS-SAC), dissenyat per minimitzar l'impacte de l'alliberament d'aigua carregada de nutrients a la reserva natural dels Aiguamolls de l'Empordà (Girona, Espanya).The continuous delivery of nutrients, mainly phosphate and nitrogen, is the major cause of eutrophication of aquatic environments. Treatment technologies based on constructed wetlands have been applied to reduce the levels of nitrogen as a cost-effective alternative compared to conventional treatment methods. The nitrogen removal efficiency in wetlands relies on the presence of plants and the alternation of aerobic and anaerobic conditions to promote both nitrification and denitrification. Although the role of emergent macrophytes in such systems is largely recognized, their contribution to the overall treatment process has not been quantified very frequently. We have investigated the microbial nitrification and denitrification activities in relation to two plant species in a free water surface constructed wetland (FWS-CW), designed to minimize the impact of nutrient release into the Natural Reserve of Els Aiguamolls de l'Empordà (Girona, Spain).
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Chang, Yu-Feng, e 張鈺鋒. "Cometabolism Dechlorination of trichloroenthene by Nitrifying Bacteria". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/74242944971561910057.
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碩士國立中山大學
環境工程與科學系
85
Pure culture of ammonia-oxidizing bacteria (Nitrosomonas europaea) has been found to be capable of degrading trichloroethylene (TCE) through the cometabolism with ammonia by ammonia monooxygenase (AMO) existing on the membrane of the bacteria. However, no further work has been studied on this enzymatic cometabolism by using enriched or mixed cultures. Hence, the purposes of this study is to investigate the cometabolic biodegradability of TCE by using an enriched nitrifying culture initially sampled from a human body waste treatment plant. The tests were run dark brown glass bottles with volume of 150mL. Initially, the test sample, containing the enriched nitrifying culture, ammonia (NH3), sodium bicarbonate (NaHCO3) and TCE mixed together with a total volume of 125 mL, was added into a test bottle. Thus, there was still 25mL void volume left in the bottle in order to supply oxygen depleted by nitrifying bacteria during test. Then, the bottle was sealed by a Teflon cover and shaked in skaking table to keep the sample liquor complete mixed in a closed batch system. During the test, samples were taken daily for analyses until no further changes in concentrations of TCE or NH3 left in the samples. The items analyzed included pH, TCE (GC-FID), NH3 (colorimetry), NO2, and NO3 (IC). Different concentrations of the cultured bacteria (MLVSS: 36.8, 65.4, 105.4, and 141.2 mg/L), NH3 (12 and 16 mg/L as N), and TCE (125, 200, and 300 ppb) were prepared and mixed in the sample liquor applied to the batch system in the tests. Besides, sufficient amounts of NaHCO3 were also added into the mixed liquor as buffering. The experimental results showed that the higher the concentrations of TCE (300 ppb) were applied, the larger amounts of TCE (140ppb) were removed and the lower the removal efficiencies (38%) were achieved, lower under same concentrations of the bacteria (36.8 mg/L VSS) and NH3 (16 mg/L as N). Learned from the accumulation of NH3 in the system, it was inferred that TCE showed inhibition to ammonia oxidation in initial applied concentrations higher than 200 ppb. According to the results of this test, the optimal initial concentration of TCE applied to the system would be 125 ppb for cometabolic degradation of TCE by the enriched nitrying culture without showing inhibitory effects to nitritification. However, when the biomass concentrations of the culture were increased from 36.8 up to 141.2 mg/L VSS under similar TCE (130 ppb) and NH3 (12 mg/L as N) levels, both of the amounts and removal efficiencies of TCE were increased. It was derived that the amounts of TCE removel through cometabolism were proportional to the amounts of nitrifying biomass which could produce AMO. According to the measuring results, the specific TCE removal rate were increased with a decreased with a decreased biomass applied with an average value of 0.847 (μg TCE removed/day-mg VSS). It was concluded that an enriched nitrifying culture could cometabolize TCE well as long as the environment was provided with sufficient NH3 and O2, suitable pH, and the TCE concentrations below inhibitory levels.
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Kundu, Balaram. "Biochemical and bioenergetic aspects of denitrification in `Rhodopseudomonas sphaeroides` forma sp. `denitrificans`". 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phk968.pdf.
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Buda, Anthony R. "Tracing stream nitrate in a Central Pennsylvania mixed land-use basin using stable isotopes, bacteria, and inorganic chemicals". 2007. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2176/index.html.
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Song, Weining 1958. "Some aspects of the utilization of inorganic nitrogen compounds and carbon compounds by "Nitrobacter hamburgensis"". 1987. http://web4.library.adelaide.edu.au/theses/09A/09as724.pdf.
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Lee, Yung-Wen, e 李永文. "Isolation and Phylogenetic Analysis of Nitrifying Bacteria for Aerobic Composting". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/99738770060793039868.
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碩士國立中興大學
獸醫微生物學研究所
91
This study aimed to isolate nitrifying bacteria for aerobic composting and to determine their phylogenetic relationship. The mass amount of ammonia produced during aerobic composting is converted into nitrite or nitrate mainly by aerobic nitrifying bacteria. Using the ammonia sulfate enrichment medium, we obtained nine isolates of ammonia-oxidizing bacteria from compost samples. Among these isolates, five isolates, designated as A3, A21, A24, A31 and A34 were Gram negative bacteria. Four isolates, including B2, B21, B22 and B23 were Gram postive bacteria. Based on the morphology and staining characteristics, we divided the nine isolates of ammonia-oxidizing bacteria into four groups. Among them, A31, A34 and B21 were identified as Aeromonas encheleia, Aeromonas hydrophila DNA group 1 and Corynebacterium jeikeium, respectively, by using Biolog Microstation System that analyzes the biochemical characteristics of bacteria. Obtaining the 16S rDNA sequences further allowed us to determine A3 of group 1 as Agrobacterium sp., A21 of group 2 as Agrobacterium tumefaciens, B2 of group 4 as Brevundimonas diminuta. Finally, primers were synthesized according to the conserved region of ammonia monooxygenase (AMO) gene A (amoA), specific DNA fragments were amplified from bacterial isolates by PCR, and DNA sequences were aligned with amoA of ammonia-oxidizing bacteria. The results showed that DNA fragment amplified from A21 had 49.4％ similarity with Nitrosospira sp. LT2Fb and that from A24 had 50.5％ similarity with Nitrosomonas sp. Nm59, which were autotrophic ammonia-oxidizing bacteria.
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Duddleston, Khrystyne Noel. "Properties of methyl bromide cooxidation by ammonia-oxidizing bacteria". Thesis, 1998. http://hdl.handle.net/1957/33568.
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Ely, Roger L. "Effects of substrate interactions, toxicity, and bacterial response during cometabolism of chlorinted solvents by nitrifying bacteria". Thesis, 1996. http://hdl.handle.net/1957/34644.
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黃惠貞. "STUDY FOR THE DETECTION METHOD OF NITRIFYING AND DENITRIFYING BACTERIA BY PCR". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/18547186074723306605.
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碩士大同大學
生物工程研究所
90
For health and environmental protection, municipal and industrial wastewaters have to be treated. Wastewater with ammonia-nitrogen, generally treated with mixed microbial populations, is produced by domestic wastewater, and wastewater from livestock and manufacture about food, ABS plastic, petroleum, and semiconductor at a large amount. The directly determination of the growths and distributions of relative bacteria are less or unsuccessful because of its complexity of populations in activated sludge. Due to the improvement of technology for molecular biology, the amounts and identify of the species can be directly determinated. There are many enzymes involved in nitrification of nitrogen cycle. Compare the genes sequences to design the primer pairs for nosZ, norB, nirS, and nirK. These primer pairs and the universal primer of 16S rDNA with the genomic DNAs of Alcaligenes xylosoxidans, Bacillus cereus, E. col, Paracoccus denitrificans, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas stutzer, Rhodobacter sphaeroides carry out the polymerase chain reaction for the rapidly determination of denitrifying bacteria. Pseudomonas fluorescens CCRC 16016 can react properly with almost nirS primer pairs, and Alcaligenes xylosoxidans CCRC12838 with nirK pimer pairs can produce the expect PCR product. However, norB primers can’t react with bacterial genomic DNA, and nosZ primers are specific to Alcaligenes faecalis DNA. So these primer pairs of the two genes are unsuitable for the detection of denitrifying bacteria. Isolate the bacterial genomic DNA from the activated sludge in treatment tank of wastewater with nitrogen compounds to do PCR with nirK and nirS primers. nirS1f-nirS3r, nirS1f-nirS7r, nirS2f-nirS7r, and nirS4f-nirS6R primer pairs can produce correct DNA fragments, and the nirK primer pairs are only the nirK1f-nirK5r primer pair with positive reaction. Thus, these primer pairs can be used for the determination of nitrifying bacteria in treatment-tank of wastewater. Additionally, used the designed amoA primer pairs, according to the AMO gene, to determinate the nitrifying bacteria in nitrifying tank, but they were inappropriate.
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Yuan, Shi-Lung, e 袁熙隆. "Nitrification Performance and Microbial Ecology of Nitrifying Bacteria in Swine and Municipal WWTP". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/93992258125953540890.
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碩士國立成功大學
環境工程學系碩博士班
94
This study evaluate microbial ecology and performance of nitrification of active sludge in different municipal and swine waste water treatment plant. Besides of traditional method to investigate characteristic of waste water, performance of nitrification and dynamic nitrification experiment of active sludge, this study used molecular biology techniques - terminal restriction fragment length polymorphism(T-RFLP) to investigate population transfer of ammonia oxydizing bacteria(AOB) and nitrite oxydizing bacteria (NOB). The subjec this syudy investigate contain a municipal waste water treatment plant and a swine waste water treatment plant. Ammonium in swine waste water inflow has reached to 215~245 mg N/L, and nitrate in outflow has reached to 180~210 mg N/L. Nitrite accumulation in outflow has reached to 5~15 mg N/L with totally nitrification effency more than 70%. TKN in municipal waste water inflow is only one of ten in swine waste water inflow. Most of TKN is ammonium with 60~80% nitrification transform efficiency. No obvious nitrite accumulation in municipal waste water outflow. T-RFLP in this study compose of 16S rDNA and fuctional gene amoA (Park et al., 2002). In 16S rDNA based T-RFLP result, Nitrosomonas is dominant AOB in municipal and swine waste water treatment without significant Nitrosospira signal. Long term dominant NOB in this two waste water treatment are Nitrobacter and Nitrospira. In amoA based T-RFLP result, Nitrosomonas europaea is long term dominant in swine waste water treatment. Besides of Nitrosomonas europaea, amoA based T-RFLP detected signal of Nitrosospira, N. communis and N. cryotolerans which exist in high nitrogen condition in swine waste water treatment. Nitrosomonas oligotropha is long term dominant AOB in municipal waste water treatment with low nitrogen condition comparing with swine waste water treatment. Moreover, this study used cloning-sequencing experiment to investigate AOB in municipal and swine waste water treatment. In cloning-sequencing results, Nitrosomonas europaea is dominant AOB in swine waste water treatment, and Nitrosomonas oligotropha and Nitrosomonas sp. Nm143 lineage is dominant AOB in municipal waste water treatment.
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Ramdhani, Nishani. "Detection and quantification of nitrifying bacteria from South African biological nutrient removal plants". Thesis, 2013. http://hdl.handle.net/10321/874.
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Submitted in fulfillment for the requirements for the Degree of Doctor of Technology: Biotechnology, Durban University of Technology, 2012.Nitrification is a crucial step in biological nutrient removal (BNR) processes, mostly carried out by a group of nitrifying bacteria which includes ammonia-oxidising bacteria (AOB) and nitrite-oxidising bacteria (NOB). Nitrification failure has proven to be a common operational problem in full-scale wastewater treatment plants (WWTP) since nitrifying bacteria are very sensitive to sudden changes in environmental or plant operating conditions. The current investigation was carried out to advance our understanding of the distribution of nitrifying bacterial populations and their performance at three different BNR plants in KwaZulu-Natal, South Africa. The latest molecular techniques such as fluorescent in situ hybridisation (FISH)-confocal scanning laser microscopy (CSLM), polymerase chain reaction (PCR) and real-time quantitative PCR (Q-PCR) were applied to detect and quantify nitrifying bacteria. When using FISH to target the nitrifying population, it necessitated optimising pre-treatment protocols of the samples to improve accuracy during quantification. Sonication was found to be the superior method of dispersion based on the least disruption of nitrifier cell integrity, irrespective of the sludge type. The effect of plant configurations and wastewater characteristics on the distribution of the nitrifying bacterial population and subsequently on the nitrification performance was evaluated using FISH and PCR. FISH results revealed the dominance of Nitrosomonas (AOB), Nitrobacter (NOB) and Nitrospira (NOB) for all BNR plants. The 16S rRNA analysis of PCR products using genus-specific primers, revealed the presence of more than one species of the same group at these plants. Nitrosomonas spp. including Nitrosomonas halophila, Nitrosomonas eutropha, Nitrosomonas europaea, Nitrosomonas aestuarii and an unidentified Nitrosomonas spp. were found to dominate among the AOB and Nitrobacter vulgaris, Nitrobacter alkalicus, Nitrobacter hamburgensis and an unidentified Nitrobacter spp. were the dominant species for NOB. Among these species, Nitrosomonas aestuarii, Nitrosomonas europaea, Nitrobacter hamburgensis were detected only from the industrial wastewater samples. The efficiency of two commonly used techniques viz., FISH and Q-PCR for the detection of nitrifiers from WWTP were also studied and compared, specifically targeting Nitrobacter sp. Even though there were slight variations in the quantification results, changes in the Nitrobacter community at these plants were consistent for both FISH and Q-PCR results. Both techniques have their own limitations and advantages. This study has helped to add to the platform of understanding the distribution and activity of nitrifying bacteria by correlating population dynamics with the operational parameters at full-scale level. The observations made in this study will assist researchers and engineers to minimise future nitrification failure at full-scale BNR plants. This study also confirmed the highly complex activities of wastewater treatment processes, which is dependant on a number of factors. Specific AOB or NOB predominant in wastewater rather suggests that the wastewater type and characteristics may contribute to significantly different microbial environments. Among the AOB, Nitrosomonas dominated at all BNR plants throughout the study period and for NOB both Nitrobacter and Nitrospira were found in significant numbers but their dominance varied across the plants. These dissimilar, distinct distribution patterns could be attributed to their environment which in turn impacted on the nitrification performance of the system. It was also noted that the co-existence of more than one group of these communities at the same plant could help the plant escape complete functional failures such as nitrification, due to sudden changes in temperature and substrate concentrations, as this function can be performed by different groups. Although it would have been meritorious to conduct a nitrogen balance in this study, this was not possible since the research focused on full-scale systems.
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Chang, Yoa Chuan, e 張耀泉. "The Study of Nitrifying Bacteria Immobilized in Immobilized Resin Pellets Add-in A2/O process". Thesis, 1994. http://ndltd.ncl.edu.tw/handle/45560240578608191713.
Texto completo da fonteResumo:
碩士國立中央大學
環境工程研究所
82
A2/O法添加固定化硝化菌擔體併同去除碳、氮、磷之處理程序乃將傳統厭 氧-缺氧-好氧活性污泥法( A2/O Process，Anaerobic-Anoxic-Oxide Activated Sludge Process )加以改良，在好氧段加入從日本引進的硝化 菌擔體，成為固定化硝化菌擔體及活性污泥法併用之程序，以改進傳統 A2/O法的缺點。本研究利用實驗室模廠進行連續操作試驗，以模擬都市污 水之人工合成基質為處理對象，控制進流水濃度為TBOD5 210mg/L、TCOD 300mg/L、氨氮 20mg/L、有機氮 20mg/L、總磷 5~5.5mg/L，變動總水力 停留時間 (10， 8，6小時 )、污泥迴流率( 0.5 )、混合液循環率(1，2 ，3，4)進行實驗。並從各水力停留時間選取一組組作對照的無擔體空白 試驗，共15組試程。評估其脫氮及除磷效果及最適操作參數，藉以瞭解其 處理特性。本處理程序對於有機碳的去除效果相當良好，當總水力停留時 間 10小時以上，即可將氨氮完全轉化，顯示好氧槽置入固定化硝化菌擔 體可使傳統硝化槽體積縮小許多而達到相同的去除效果。本程序由於所使 用的固定化硝化菌擔體具有強大的硝化功能，使硝化速率較一般程序高。 在實驗設定範圍下(HRT=6∼10hr、r=0.5、R=1，2，3，4)之硝化速率( mgNH3-N/hr)及脫硝速率(mgNOx-N/hr)均以HRT=8hr，r=0.5， R=4為最大 。本程序固定化硝化菌擔體在HRT=6hr時硝化速率(mg NH3-N/hr/l擔體)最 大本程序除磷所控制及探討的影響因子有: 污泥停留時間，厭氧槽水力停 留時間，厭氧槽MLVSS濃度，好氧槽DO值。實驗結果本程序除磷效果以 HRT =8hr 為最佳。綜合15個試程，去除碳、氮、磷之最適操作參數為水 力停留時間8小時，污泥迴流比 r=0.5、混合液循環比R=4 。綜觀本A2/O 法添加固定化硝化菌擔體同時去除有機碳及氮、磷之處理程序可將傳統厭 氧好氧法同時除氮除磷程序的缺失改善。經單一化之處理程序具有同時去 除有機碳與氮、磷的作用，可簡化多槽操作的複雜性及節省個別設置。 The propose of this study is to imprprocess. Nitrifiers immobilized in polyethylene-glycol resin (Nitrifying pellets) borrowed from Japan are mixed with activated sludge in the nitrification tank. Due to the high nitrifying activity of pellets,the detention time for nitrification can be shortened within a few hours. The process is inleted synthetic municipal wastewater and return sludge to the anaerobic tank for releasing phosphate and adsorpting soluble organic matter. Mixed liquid recycle from aerobic tank to the anoxic tank is for denitritrification. This research introduces the activity of nitrifying pellets and its treatment performances as nitrogen removal process. In the research.the optimun operation parameter is ：HRT=10hr，r=0.5， R=4。
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Ke, Shih-Ghieh, e 柯世傑. "Using molecular biology method to calculate the numbers of nitrifying bacteria and their nitrification rates in different samples". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/88065183515489328945.
Texto completo da fonteResumo:
碩士東吳大學
微生物學系
93
Nitrification is one of the most important step is the nitrogen cycle, this series of reactions are responsible for chemoautotrophic nitrobacteria, therefore the chemoautotrophic nitrobacteria play an important role in nitrogen cycle. Nitrobacteria grow in a slow rate, and during their growth, they produce some acidic and toxic metabolites and that will inhibit their growth too. Because of the slow growth rate, that increases the contaminant opportunity by other micro organisms, for these reason it risen the difficulty of culturing and purifying the nitrobacteria, and limit the counting method. According to those limitations, this study would like to use the molecular biology method to enumerate the nitrobacteria in the sample fast and precisely. We use fluorescent in situ hybridization method (FISH). First, we choose ammonia- oxidizing bacteria and nitrite- oxidizing bacteria 16S rDNA from the gene bank, then alignment by GCG SeqWeb software, to find out the the genus specific region sequences to be the FISH probe Nso1225, and Nit3. And to make sure the specificity of the probe, we use the probe as one side primer to do the PCR test. The result shows no cross reaction with other species of bacteria. The FISH result shows that the optima conditions of different probes are Eub338: 0% formamide, 0.9M NaCl, Nso1225: 35% formamide, 0.08MNaCl, Nit3: 40% formamide, 0.056M NaCl. Our study detects the ammonia- oxidation rate and the nitrite- oxidation rate of the sample, to find out the linkage of nitrification rate and the numbers of the ammonia- oxidizing bacteria and the nitrite- oxidizing bacteria. According to the results, the generation time of the ammonia- oxidizing bacteria in the medium are 9 hours, and the generation time of the nitrite- oxidizing bacteria in the medium is 12 hours. The ammonia-oxidation rate of the ammonia- oxidizers is 2.58 × 10-7 μmol/cell.h, and the nitrite-oxidation rate of the nitrite-oxidizers is 6.13 × 10-8 μmol/cell.h. We also applied this experiment in soil sample, the ammonia- oxidation rate in the soil is 1.69 × 10-7 μmol/cell.h, and the nitrite-oxidation rate is 4.17 × 10-8 μmol/cell.h. The amount of ammonium-oxidizers and nitrite-oxidizers in the soil are counted by Flow Cytometry after hybridized by specific probes. The ratio of ammonium -oxidizers and nitrite-oxidizers are 14.57% and 12.65%. According to our results, use both FISH and Flow Cytometry method to calculate the numbers of nitrifying bacteria and their nitrification rates in different samples more precisely.
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Daims, Holger [Verfasser]. "Population structure and functional analyses by in situ techniques of nitrifying bacteria in wastewater treatment plants / Holger Daims". 2001. http://d-nb.info/963771582/34.
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Tsai-Chien, Chen, e 蔡建成. "Kinetics of Nitrification/Denitrification in Single-Sludge Reactor System(Involving Distributed Fractions of Nitrifying Bacteria and Denitrifying Reductases)". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/23542471492228297297.
Texto completo da fonteResumo:
碩士國立成功大學
環境工程學系
89
A nitrification-denitrification kinetic model of a single-sludge reactor system (an anoxic denitrification reactor followed by an aerobic nitrification reactor), accounting for the distributed fractions of Nitrosomonas, Nitrobacter, nitrate-reductase and nitrite-reductase, was proposed. By using sludge taken from each bioreactor of the steady-state single-sludge reactor system, independent batch experiments were also performed to estimate the distributed fractions of nitrifying bacteria and denitrifying reductases. When treating nitrogen-containing wastewater (i.e., similar to chemical- coagulation/dissolved-air-flotation pretreated slaughterhouse wastewater; COD = 220 — 450 mg/L, NH4+-N = 120 mg/L, TP = 20 mg/L), the single-sludge reactor system was very effective for nitrification-denitrification under proper operating conditions (NH4+-N loading, sludge recycle ratio, mixed-liquor recycle ratio, and MCRT). According to material-balance calculations using operating conditions and performance data of the single-sludge reactor system (eight test runs), the specific nitrification rate of the aerobic nitrification reactor and the specific denitrification rate of the anoxic denitrification reactor were 0.18 — 0.21 mg NH4+-N/mg VSS-d and 0.23 — 0.30 mg NOx--N/mg VSS-d, respectively. The ratio of CODutili/NOx--Nred and the phosphorus content of waste sludge determined from the operating conditions and performance data of the single-sludge reactor system were 3.9 — 5.2 and 4.29% — 8.16%. In addition, the measured alkalinity changes in the single-sludge reactor system were close to the theoretical, indicating that the measurement of alkalinity changes can be adequately used for monitoring the single-sludge reactor system. From independent batch experiments (enrichment culture), two-step nitrification followed Monod-type kinetics with biokinetic constants kn1, Ks,n1, kn2, and Ks,n2 of 1.73 mg NH4+-N/mg VSS-d, 1.71 mg NH4+-N/L, 2.27 mg NO2--N/mg VSS-d, and 12.7 mg NO2--N/L, respectively. Meanwhile, two-step denitrification followed zero-order and Monod-type kinetics, respectively, with biokinetic constants kdn1, kdn2, and Ks,dn2 of 3.56 NO3--N/mg VSS-d, 0.74 mg NO2--N/mg VSS-d, 0.14 mg NO2--N /L. When steady states were reached in the single-sludge reactor system, sludges were respectively removed from the anoxic denitrification reactor and the aerobic nitrification reactor. From independent batch experiments using such sludges, the estimated distributed fractions of Nitrosomonas, Nitrobacter, nitrate-reductase and nitrite-reductase were 0.14 — 0.34, 0.16 — 0.31, 0.06 — 0.14, and 0.32 — 0.47, respectively. Obviously, the distributed fraction of nitrite-reductase was the greatest. This finding confirms further our previous performance data that the accumulation of NO2--N did not occur in the single-sludge reactor system during the entire period of operation. By placing biological parameter values and operating conditions of the single-sludge reactor system into the kinetic model, the calculated NH4+-N, NO2--N and NO3--N concentrations in the effluent of the anoxic denitrification reactor and the aerobic nitrification reactor as well as the calculated NH4+-N and TN removal efficiencies were all in fairly good agreement with the experimental data. Accordingly, the proposed kinetic model can be adequately used to predict treatment performance of the single-sludge reactor system. Finally, according to simulated results using the verified kinetic model, an optimal design and operation of the single-sludge reactor system is inevitably necessary to result in proper distributed fractions of Nitrosomonas, Nitrobacter, nitrate-reductase and nitrite-reductase, and thus effective NH4+-N and TN removal efficiencies can then be achieved.
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Thomas, William J. "Identification and characterization of type III effector proteins in plant-associated bacteria". Thesis, 2012. http://hdl.handle.net/1957/29206.
Texto completo da fonteResumo:
Symbioses between microbes and multicellular eukaryotes are found in all biomes, and encompass a spectrum of symbiotic lifestyles that includes parasitism and disease, commensalism, and mutually beneficial interdependent host-microbe relationships. Regardless of outcome, these symbiotic lifestyles are governed by a complex molecular "courtship" between microbe and potential host. This courtship is the primary determinant of the host range of a given microsymbiont. Host immunity poses a formidable barrier to the establishment of host-microbe relationships, and the majority of microbial suitors will be thwarted by it. Only by successfully "wooing" the host cell's immune defenses with the appropriate molecular signals can a microsymbiont successfully colonize its host.
A strategy common to microsymbionts across the spectrum of symbiotic lifestyles and host organisms is the delivery of microbial-encoded effector proteins into the cytoplasm of host cells to manipulate the host cell's molecular machinery for the purposes of subverting host immunity. Bacteria, in particular, have adapted a number of secretion systems for this purpose. The most well-characterized of these is the type III secretion system (T3SS), a molecular apparatus that specializes in injecting type III effector (T3Es) proteins directly into host cells. The work in this thesis focuses on T3Es of plant-associated bacteria, with particular emphasis on mutualistic bacteria. We present evidence that collections of T3Es from Sinorhizobium fredii and Bradyrhizobium japonicum are, in stark contrast to those of phytopathogenic bacteria, in a co-evolutionary equilibrium with their hosts. This equilibrium is characterized by highly conserved T3E collections consisting of many "core" T3Es with little variation in nucleotide sequence. The T3Es of Mesorhizobium loti MAFF303099 suggest a completely different picture of the evolution of T3Es. MAFF303099 recently acquired its T3SS locus, and the work in this thesis provides an evolutionary snapshot of a mutualist that is innovating a T3E collection primarily through horizontal gene transfer. Collectively, this work represents the first comprehensive catalog of T3Es of rhizobia and, in the case of Sinorhizobium and Bradyrhizobium, the first evidence of purifying selection for T3Es.Graduation date: 2012
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Mintie, Ann. "Community profiles of ammonia oxidizers across high-elevation forest-to-meadow transects". Thesis, 2002. http://hdl.handle.net/1957/28834.
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In recent years considerable interest has been shown in the diversity of ammonia-oxidizing
bacteria in soil communities. The majority of the research has been carried
out in Northern Europe where soils have received high atmospheric inputs of nitrogen
over the past two centuries. In contrast, although much work has been conducted on
nitrogen cycling processes in nitrogen limited forest ecosystems in western North
America, no studies have examined the characteristics of ammonia-oxidizing
communities in those environments.
I was interested in measuring nitrification potential along a high-elevation
temperate meadow-to-forest gradient, and characterizing the ammonia-oxidizing
communities along that gradient using both molecular and culturing methods. Two
experimental sites (Lookout and Carpenter) were chosen in the H.J. Andrews
Experimental Forest, located in the western Cascade Range of Oregon, at elevations of
approximately 1500 meters. Although nitrification potential rates (NPRs) between sites
were not significantly different (P=0.544), variation was observed both within and
between sites for specific vegetation types. NPRs were significantly lower in forest (F)
soil samples than in meadow (M) soil samples, averaging 5 and 2% of meadow NPRs
at Lookout and Carpenter, respectively. In meadow soil samples, most probable number
(MPN) population densities of ammonia-oxidizers ranged from 0.6 to 2.6 x 10⁴ cells
gram⁻¹ of oven dry soil and 0.9 x 10³ to 1.1 x 10⁵ cells g⁻¹ OD soil at Lookout and
Carpenter, respectively. In forest soil samples, population densities ranged from
undetectable to 1.1 x 10⁴ cells g⁻¹ OD soil, and 0.9 x 10² to 2.3 x 10³ cells g⁻¹ OD soil
at Lookout and Carpenter, respectively.
Microbial community DNA was amplified using primers to the ammonia
monooxygenase subunit A. Terminal restriction fragments polymorphism analysis with
three different restriction enzymes (CfoI, TaqI, and AluI) revealed community profiles
dominated by Nitrosospira species. One fragment from CfoI (66 bp) and one fragment
from AluI (392-bp) were prominent in 47 soil samples from both sites, and represented
between 32 to 100% of the Genescan fragment analyses of PCR products. A full length
fragment from AluI digests (491-bp), and three fragments from CfoI (68, 100, and 135-
bp) were found sporadically in fewer soil sample T-RFLPs, and within those samples
represented smaller percentages of total peak areas. The CfoI 135-bp fragment length
was associated primarily with M and meadow/forest (M/F) soils where it was observed
in approximately 58 and 100% of the respective transect locations. Eight isolates
recovered from soil samples were analyzed using the same molecular methods as the
field samples. The T-RFLP patterns of the isolates corresponded with many of those
found in the community fingerprints. Four unique amoA sequences were identified
among these isolates, including one that possessed the dominant T-RFLP amoA
fingerprint in soil samples. This sequence shared 99.8% similarity with Nitrosospira
sp. Ka4, a cluster 4 ammonia oxidizer isolated in Norway. Sequence analysis
phylogenetically associated the other three isolates (with unique amoA sequences) near
Nitrosospira sp. Nsp 1 and Nitrosospira briensis, both cluster 3 ammonia oxidizers.
Cloning and sequencing of soil DNA confirmed that ammonia oxidizers with these
amoA sequences were present in the soil samples. Two additional amoA sequences
were identified in clones that were 95% similar and paraphylogenetically positioned
between representatives of clusters 3 and 4. So far, these sequences have not been
found in any of the isolates analyzed.Graduation date: 2003
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Awolusi, Oluyemi Olatunji. "Evaluation of seasonal impacts on nitrifiers and nitrification performance of a full-scale activated sludge system". Thesis, 2016. http://hdl.handle.net/10321/1722.
Texto completo da fonteResumo:
Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2016.Seasonal nitrification breakdown is a major problem in wastewater treatment plants which makes it difficult for the plant operators to meet discharge limits. The present study focused on understanding the seasonal impact of environmental and operational parameters on nitrifiers and nitrification, in a biological nutrient removal wastewater treatment works situated in the midlands of KwaZulu Natal. Composite sludge samples (from the aeration tank), influent and effluent water samples were collected twice a month for 237 days. A combination of fluorescent in-situ hybridization, polymerase chain reaction (PCR)-clone library, quantitative polymerase chain reaction (qPCR) were employed for characterizing and quantifying the dominant nitrifiers in the plant. In order to have more insight into the activated sludge community structure, pyrosequencing was used in profiling the amoA locus of ammonia oxidizing bacteria (AOB) community whilst Illumina sequencing was used in characterising the plant’s total bacterial community. The nonlinear effect of operating parameters and environmental conditions on nitrification was also investigated using an adaptive neuro-fuzzy inference system (ANFIS), Pearson’s correlation coefficient and quadratic models. The plant operated with higher MLSS of 6157±783 mg/L during the first phase (winter) whilst it was 4728±1282 mg/L in summer. The temperature recorded in the aeration tanks ranged from 14.2oC to 25.1oC during the period. The average ammonia removal during winter was 60.0±18% whereas it was 83±13% during summer and this was found to correlate with temperature (r = 0.7671; P = 0.0008). A significant correlation was also found between the AOB (amoA gene) copy numbers and temperature in the reactors (α= 0.05; P=0.05), with the lowest AOB abundance recorded during winter. Sanger sequencing analysis indicated that the dominant nitrifiers were Nitrosomonas spp. Nitrobacter spp. and Nitrospira spp. Pyrosequencing revealed significant differences in the AOB population which was 6 times higher during summer compared to winter. The AOB sequences related to uncultured bacterium and uncultured AOB also showed an increase of 133% and 360% respectively when the season changed from winter to summer. This study suggests that vast population of novel, ecologically significant AOB species, which remain unexploited, still inhabit the complex activated sludge communities. Based on ANFIS model, AOB increased during summer season, when temperature was 1.4-fold higher than winter (r 0.517, p 0.048), and HRT decreased by 31% as a result of rainfall (r - 0.741, p 0.002). Food: microorganism ratio (F/M) and HRT formed the optimal combination of two inputs affecting the plant’s specific nitrification (qN), and their quadratic equation showed r2-value of 0.50. This study has significantly contributed towards understanding the complex relationship between the microbial population dynamics, wastewater composition and nitrification performance in a full-scale treatment plant situated in the subtropical region. This is the first study applying ANFIS technique to describe the nitrification performance at a full-scale WWTP, subjected to dynamic operational parameters. The study also demonstrated the successful application of ANFIS for determining and ranking the impact of various operating parameters on plant’s nitrification performance, which could not be achieved by the conventional spearman correlation due to the non-linearity of the interactions during wastewater treatment. Moreover, this study also represents the first-time amoA gene targeted pyrosequencing of AOB in a full-scale activated sludge is being done.
D