Academic literature on the topic 'Autotrophic production'
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Journal articles on the topic "Autotrophic production"
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Oh, S. E., K. S. Kim, H. C. Choi, J. Cho, and I. S. Kim. "Kinetics and physiological characteristics of autotrophic dentrification by denitrifying sulfur bacteria." Water Science and Technology 42, no. 3-4 (August 1, 2000): 59–68. http://dx.doi.org/10.2166/wst.2000.0359.
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To study the kinetics and physiology of autotrophic denitrifying sulfur bacteria, a steady-state anaerobic master culture reactor (MCR) was operated for over six months under a semi-continuous mode and nitrate limiting conditions using nutrient/mineral/buffer (NMB) medium containing thiosulfate and nitrate. Characteristics of the autotropic denitrifier were investigated through the cumulative gas production volume and rate, measured using an anaerobic respirometer, and through the nitrate, nitrite, and sulfate concentrations within the media. The bio-kinetic parameters were obtained based upon the Monod equation using mixed cultures in the MCR. Nonlinear regression analysis was employed using nitrate depletion and biomass production curves. Although this analysis did not yield exact biokinetic parameter estimates, the following ranges for the parameter values were obtained: μmax =0.12-0.2 hr-1; k=0.3-0.4 hr-1; Ks=3-10mg/L; YNO3=0.4-0.5mg Biomass/mg NO3--N. Inhibition of denitrification occurred when the concentrations of NO3--N, and SO42- reached about 660mg/L and 2,000mg/L, respectively. The autotrophic denitrifying sulfur bacteria were observed to be very sensitive to nitrite but relatively tolerant of nitrate, sulfate, and thiosulfate. Under mixotrophic conditions, denitrification by these bacteria occurred autotrophically; even with as high as 2 g COD, autotrophic denitrification was not significantly affected. The optimal pH and temperature for autotrophic denitrification was about 6.5–7.5 and 33–35 °C, respectively.
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Duarte, Carlos M., and Just Cebrián. "The fate of marine autotrophic production." Limnology and Oceanography 41, no. 8 (December 1996): 1758–66. http://dx.doi.org/10.4319/lo.1996.41.8.1758.
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Gifuni, Imma, Giuseppe Olivieri, Antonino Pollio, Telma Teixeira Franco, and Antonio Marzocchella. "Autotrophic starch production by Chlamydomonas species." Journal of Applied Phycology 29, no. 1 (September 4, 2016): 105–14. http://dx.doi.org/10.1007/s10811-016-0932-2.
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Frolov, Evgenii N., Ilya V. Kublanov, Stepan V. Toshchakov, Evgenii A. Lunev, Nikolay V. Pimenov, Elizaveta A. Bonch-Osmolovskaya, Alexander V. Lebedinsky, and Nikolay A. Chernyh. "Form III RubisCO-mediated transaldolase variant of the Calvin cycle in a chemolithoautotrophic bacterium." Proceedings of the National Academy of Sciences 116, no. 37 (August 26, 2019): 18638–46. http://dx.doi.org/10.1073/pnas.1904225116.
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The Calvin–Benson–Bassham (CBB) cycle assimilates CO2for the primary production of organic matter in all plants and algae, as well as in some autotrophic bacteria. The key enzyme of the CBB cycle, ribulose-bisphosphate carboxylase/oxygenase (RubisCO), is a main determinant of de novo organic matter production on Earth. Of the three carboxylating forms of RubisCO, forms I and II participate in autotrophy, and form III so far has been associated only with nucleotide and nucleoside metabolism. Here, we report that form III RubisCO functions in the CBB cycle in the thermophilic chemolithoautotrophic bacteriumThermodesulfobium acidiphilum,a phylum-level lineage representative. We further show that autotrophic CO2fixation inT. acidiphilumis accomplished via the transaldolase variant of the CBB cycle, which has not been previously demonstrated experimentally and has been considered unlikely to occur. Thus, this work reveals a distinct form of the key pathway of CO2fixation.
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Trentin, Giulia, Veronica Lucato, Eleonora Sforza, and Alberto Bertucco. "Stabilizing autotrophic cyanophycin production in continuous photobioreactors." Algal Research 60 (December 2021): 102518. http://dx.doi.org/10.1016/j.algal.2021.102518.
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Olivieri, Giuseppe, Renato S. Coellho, Telma T. Franco, Antonino Pollio, and Antonio Marzocchella. "Polysaccharides production by autotrophic cultures of microalgae." New Biotechnology 31 (July 2014): S17. http://dx.doi.org/10.1016/j.nbt.2014.05.1651.
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Jeong, Byoung Kyong, Kazuhiro Fujiwara, and Toyoki Kozai. "Carbon Dioxide Enrichment in Autotrophic Micropropagation: Methods and Advantages." HortTechnology 3, no. 3 (July 1993): 332–34. http://dx.doi.org/10.21273/horttech.3.3.332.
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Autotrophic micropropagation has advantages over conventional micropropagation and can reduce costs of plantlet production. In this article, we describe advantages of autotrophic micropropagation and a practical and formulated method of enriching culture rooms with CO2.
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Geertz-Hansen, O., C. Montes, C. M. Duarte, K. Sand-Jensen, N. Marbá, and P. Grillas. "Ecosystem metabolism in a temporary Mediterranean marsh (Doñana National Park, SW Spain)." Biogeosciences Discussions 7, no. 4 (August 26, 2010): 6495–521. http://dx.doi.org/10.5194/bgd-7-6495-2010.
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Abstract. The metabolic balance of the open waters supporting submerged macrophytes of the Doñana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community was net autotrophic with net community production rates averaging 0.61 g C m−2 d−1, and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic being 42 to 255 μE m−2 s−1, below which communities became net heterotrophic. Examination of the contributions of the benthic and the pelagic compartments showed the pelagic compartment to be strongly heterotrophic (average P/R ratio = 0.27), indicating that the metabolism of the pelagic compartment is strongly subsidised by excess organic carbon produced in the strongly autotrophic benthic compartment (average P/R = 1.58).
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Geertz-Hansen, O., C. Montes, C. M. Duarte, K. Sand-Jensen, N. Marbá, and P. Grillas. "Ecosystem metabolism in a temporary Mediterranean marsh (Doñana National Park, SW Spain)." Biogeosciences 8, no. 4 (April 19, 2011): 963–71. http://dx.doi.org/10.5194/bg-8-963-2011.
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Abstract. The metabolic balance of the open waters supporting submerged macrophytes of the Doñana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community (benthic + pelagic) was net autotrophic with net community production rates averaging 0.61 g C m−2 d−1, and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic ranging from 42 to 255 μE m−2 s−1, with net heterotrophic at lower irradiance. Examination of the contributions of the benthic and the pelagic compartments showed the pelagic compartment to be strongly heterotrophic (average P/R ratio = 0.27), indicating that the metabolism of the pelagic compartment is highly subsidised by excess organic carbon produced in the strongly autotrophic benthic compartment (average P/R = 1.58).
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Ronan, Patrick, Otini Kroukamp, Steven N. Liss, and Gideon Wolfaardt. "Interaction between CO2-consuming autotrophy and CO2-producing heterotrophy in non-axenic phototrophic biofilms." PLOS ONE 16, no. 6 (June 15, 2021): e0253224. http://dx.doi.org/10.1371/journal.pone.0253224.
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As the effects of climate change become increasingly evident, the need for effective CO2 management is clear. Microalgae are well-suited for CO2 sequestration, given their ability to rapidly uptake and fix CO2. They also readily assimilate inorganic nutrients and produce a biomass with inherent commercial value, leading to a paradigm in which CO2-sequestration, enhanced wastewater treatment, and biomass generation could be effectively combined. Natural non-axenic phototrophic cultures comprising both autotrophic and heterotrophic fractions are particularly attractive in this endeavour, given their increased robustness and innate O2-CO2 exchange. In this study, the interplay between CO2-consuming autotrophy and CO2-producing heterotrophy in a non-axenic phototrophic biofilm was examined. When the biofilm was cultivated under autotrophic conditions (i.e. no organic carbon), it grew autotrophically and exhibited CO2 uptake. After amending its growth medium with organic carbon (0.25 g/L glucose and 0.28 g/L sodium acetate), the biofilm rapidly toggled from net-autotrophic to net-heterotrophic growth, reaching a CO2 production rate of 60 μmol/h after 31 hours. When the organic carbon sources were provided at a lower concentration (0.125 g/L glucose and 0.14 g/L sodium acetate), the biofilm exhibited distinct, longitudinally discrete regions of heterotrophic and autotrophic metabolism in the proximal and distal halves of the biofilm respectively, within 4 hours of carbon amendment. Interestingly, this upstream and downstream partitioning of heterotrophic and autotrophic metabolism appeared to be reversible, as the position of these regions began to flip once the direction of medium flow (and hence nutrient availability) was reversed. The insight generated here can inform new and important research questions and contribute to efforts aimed at scaling and industrializing algal growth systems, where the ability to understand, predict, and optimize biofilm growth and activity is critical.
Dissertations / Theses on the topic "Autotrophic production"
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Melville, Andrew J., and n/a. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish." Griffith University. School of Environmental and Applied Science, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060824.144508.
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The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.
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Melville, Andrew J. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367080.
Full textAbstract:
The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.Thesis (Masters)
Master of Philosophy (MPhil)
School of Environmental and Applied Science
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Ferguson, April A. "Autotrophic and heterotrophic bacterial carbon production in two temperate lakes with contrasting food web structure." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ33481.pdf.
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Rackliffe, Daniel Riley. "Spatial Heterogeneity of Ecosystem Metabolism in a Shallow Wetland." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5757.
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Spatial heterogeneity in ecosystem metabolism may play a critical role in determining ecosystem functions. Variation in ecosystem metabolism between macrophyte patches in shallow wetlands at the extremes of freshwater habitats has not been investigated. We estimated ecosystem metabolism in mesocosms containing different macrophytes using 24-hour oxygen curves to test our hypotheses: (1) net aquatic production (NAP) during spring and summer would be similar among algal patches (metaphyton and Chara), (2) NAP in algal patches would be greater than patches dominated by the vascular plant Potamogeton foliosus, (3) heterotrophy and anaerobiosis would be greatest in patches dominated by Lemna, and (4) the pond would be autotrophic in the spring and fall but heterotrophic in the summer. We found that different patches generated differences in NAP but not always as we predicted. NAP was different among algal patches in the spring and summer, and only metaphyton was more heterotrophic than P. foliosus. In the summer Chara and Lemna patches were heterotrophic and metaphyton became autotrophic. As predicted, the pond was net autotrophic in the spring and heterotrophic in the summer with an absence of patchiness in fall attributed to the dominance of Lemna. This research suggests the importance of macrophyte patchiness in wetlands in determining patterns of ecosystem metabolism despite challenges in measuring 24 hour oxygen curves (e.g. oxygen supersaturation). Consequently, macrophyte traits may be important in determining spatial heterogeneity of ecosystem metabolism in shallow ponds.
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Degrenne, Benoît. "Production d'hydrogène par Chlamydomonas reinhardtii en photobioréacteur : analyse des conditions de culture et mise en place d'un protocole autotrophe." Nantes, 2009. http://www.theses.fr/2009NANT2031.
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La production d'hydrogène par des microalgues apparaît comme intéressante dans l'optique de la production d'un vecteur énergétique sans émissions de gaz à effet de serre. En effet, la microalgue verte Chlamydomonas reinhardtii est capable de traduire cet hydrogène à partir d'eau. La production d'hydrogène, due à la présence d'une enzyme [Fe] – Hydrogénase est inhibée en présence d'oxygène. Le protocole de carence en soufre a ainsi été developpé par Melis et al. (2000), la production d'oxygène lors de la croissance des algues et la production d'hydrogène en conditions anaérobiques et en présence de lumière étant séparées dans le temps. Le but de cette thèse est de mieux comprendre les différents processus menant à la production d'hydrogène afin de les optimiser voire de proposer des protocoles de production alternatifs grâce au contrôle poussé des conditions de culture permis par la culture en photobioréacteur. L'étude de la croissance de Chlamydomonas reinhardtii montre que les conditions anaérobiques interviennent lorsqu'une phase sombre, caractérisée par la fraction est présente dans le réacteur. Cette valeur a été déterminée pour les conditions mixotrophes ( γ-1) et autotrophes (γ=0. 18). L'optimisation des conditions opératoires par modification du protocole de carence en soufre a permis d'appliquer ce protocole sur milieu autotrophe. Les résultats montrent que la productivité maximale en hydrogène est très semblable (1,9ml h2 /g. 1) quelles que soient les conditions initiales appliquées. Finalement des essais de découplage de voies de production d'hydrogène ont été entrepris. Le mode de culture chemostat, avec ou sans limitation minérale, permet de réguler la teneur en amidon ainsi que la concentration en biomasse. Les résultats montrent que le protocole de carence en soufre reste à ce jour le plus efficace par rapport à un protocole basé sur une autre carence minérale (azote notamment)Hydrogen production by microalgae seems to be interesting in the context of clean hydrogen production. The unicellular green algae Chlamydomonas reinhardtii is indeed able to produce photo synthetically hydrogen gas from water. Hydrogen production, due to the presence of an enzyme [Fe]-hydrogenase, is inhibited in the presence of oxygen. The protocol of sulphur deprivation developped by Melis et al. (2000), allows to time separate the production of oxygen during the algae growth and the production of hydrogen in anaerobic conditions in the presence of light. The aim was here to better understand the role of culture conditions on H2 production process, and to develop new protocols using high control allowed in photobioreactor. The study of the growth of Chlamydomonas reinhardtii shows that anaerobic conditions occur when a dark area, characterized by the illuminated fraction appears in the reactor. This value has been estimated in mixotrophic condition (γ -1) and in autotrophic conditions (γ= 0. 18). Thus has allowed to develop a protocol that permit to reach anoxia and hydrogen production under light conditions without mineral starvation, based on the control of radiative light transfer inside the photobioreactor. The optimization of standard sulphur deprived protocol by using modelling tool allowed to develop this protocol in autotrophic conditions. The maximal hydrogen productivity is similar (1,9 ml H2/gl) even if different initial conditions are applied. Finally, the photobioreactor was used to decouple metabolic pathways leading to hydrogen production. A methodology based on culture chemostat mode, with or without limitation mineral, allows regulating starch content and the concentration of biomass all in a reversible manner. The result shows that the protocol of sulphur deprivation is still the most effective compared to other protocols based on other mineral limitations
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Fukaï, Eri. "Importance du picoplancton autotrophe dans la biomasse et la production primaire des eaux marines oligotrophes : Atlantique tropical oriental et mer des Sargasses." Paris 6, 1991. http://www.theses.fr/1991PA066491.
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L'importance du picoplancton autotrophe dans la biomasse et la production primaire a été étudiée dans deux régions océaniques oligotrophes : l'Atlantique tropical oriental (PIRAL), plus particulièrement la Convergence Nord Équatoriale et le Dôme de Guinée (centre et périphérie), et la mer des Sargasses (CHLOMAX). Toutes ces zones présentent des structures hydrologiques à deux couches, avec une couche homogène supérieure dépourvue de nitrates. Cette stratification entraîne des distributions verticales particulières des paramètres biologiques étudiés : organismes picoplanctoniques (cyanobactéries, eucaryotes autotrophes -eucAP-), chlorophylle et production primaire 14 c (<1 m et total). Un maximum profond de chlorophylle (MPC) existe pour toutes ces régions, situé respectivement pour PIRAL et CHLOMAX, à 40-50 m (0,7-0,8 mgchla. M-3) et à 100 m (0,4 mgchla. M-3). Au cours de PIRAL, ce MPC est constitué principalement par les cellules nanoplanctoniques et non picoplanctoniques. Néanmoins, le picoplancton autotrophe représente 40u de la biomasse phytoplanctonique sur toute la colonne d'eau et il joue un rôle important dans le haut de la couche euphotique, dans la zone pauvre en nitrates. Par contre, les cyanobactéries, étudiées au cours des deux campagnes, ne correspondent qu'a 12-24% de la chlorophylle totale et ceci met en évidence leur contribution peu importante dans la biomasse autotrophe et par conséquent, le rôle non négligeable des eucAP. De plus, le picoplancton autotrophe au cours de PIRAL contribue à environ 40% de la production primaire totale sur la colonne d'eau et de façon importante dans le haut de la couche euphotique. Les index de productivités ne présentent pas de différences significatives entre le pico- et le phytoplancton total. Le picoplancton autotrophe joue donc un rôle significatif dans les écosystèmes océaniques oligotrophes, tropicaux et subtropicaux.
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Glé, Corine. "Structure et dynamique des communautés microbiennes autotrophes et production primaire planctonique dans une lagune côtière macrotidale, le Bassin d'Arcachon : facteurs de contrôle de type bottom-up." Bordeaux 1, 2007. http://www.theses.fr/2007BOR13556.
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Le Bassin d'Arcachon, lagune côtière macrotidale, supporte une production importante d'organismes à fort intérêt économique. La connaissance de la dynamique du compartiment autotrophe est indispensable pour comprendre le fonctionnement trophique de cet écosystème. Cette étude se propose de répondre aux questions suivantes : (i) quels sont les facteurs environnementaux susceptibles de conditionner la dynamique saisonnière et spatiale du compartiment autotrophe dans la lagune ?, (ii) quel est le rôle des facterus de type bottom-up dans le contrôle de la production primaire planctonique ? et (iii) quelle est l'importance de la production primaire planctonique globale du Bassin d'Arcachon ? Pour cela, un suivi annuel haute-fréquence (pas de temps : 3-4 j) a été mené dans les eaux externes (ENE), influencées par les apports du golfe de Gascogne et les eaux internes (ENI), proches des apports continentaux. Dans l'ensemble de la baie, le cycle saisonnier est marqué par la présence de floraisons précoces de diatomées microplanctoniques (> 20 mu m) s'initiant dès février sous l'influence (i) de fenêtres anticycloniques (augmentation du rayonnement solaire pendant quelques jours consécutifs) et (ii) d' "inocula" provenant des eaux océaniques adjacentes. En été, les expériences d'enrichissements nutritifs de la production primaire montrent une intensification des limitations nutritives de la production primaire, en accord avec la chute des teneurs en nutriments (déficit en azote comparé aux rapports de Redfield). Ces limitations nutritives sont en partie responsables du changement de structure de taille de la communauté phytoplanctonique. En effet, dans les ENE où l'épuisement nutritif est sévère, la classe de taille < 20 mu m domine largement. Par contre, dans les ENI, les plus fortes concentrations nutritives (notamment de Si) soutiennent des floraisons de diatomées microplanctoniques estivales. De ce fait, les ENI se distinguent des ENE par des taux de production primaire nettement plus élevés. Avec une production phytoplanctonique intégrée sur l'année s'élevant à 103 gC. M-2. An-1, le bassin appartient aux systèmes dits "mésotrophes".
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Sun, Cheng-Hsiung, and 孫證雄. "Production and supercritical fluid extraction of lutein from Scenedesmus obliquus in an autotrophical cultivation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/41212115888761825766.
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碩士東海大學
化學工程與材料工程學系
99
In recent years, because the algae have a carbon reduction capacity, high lipid content and rich nutrient ingredients, it gradually attracted much attention. In this study, we explore three research directions by the cultivation of microalgae: (1) the effect of Scenedesmus obliquus concentration and lutein content by changing the environment or the medium composition. The results of this study indicate that an increase in CO2 percentage to 2% and light intensity to 1600 μmolm-2s-1 can enhance Scenedesmus obliquus growth to a maximum of 2.45 g/L and 2.46 g/L; salt will result in the phenomenon of cell growth retardation; methylene blue added will not have any impact. As for the effect of lutein content, 2% carbon dioxide and 1600 μmolm-2s-1 light intensity can increase to 0.40% dw and 0.47% dw; salt and methylene blue added will not cause any effect, (2) scale up experiment and explore the impact of cultivating parameters. We get a light intensity model Biomass(g/L)=0.3574*ln(modified light intensity)-4.1846, and the use of 6.0 L photoreactor verify the credibility of this equation, (3) the ability of supercritical fluid extraction whether to replace the traditional organic solvent extraction method of the possibilities. In this study, the supercritical fluid extraction of lutein is divided into four parts: (a) pressure, (b) temperature, (c) co-solvent type, (d) the optimum amount of co-solvent. The results showed that the increase of pressure and temperature in the SFE operation enhances the lutein recovery yield. However, the enhancement resulting from the increase of temperature and pressure is not significant as compared to the yield from the conventional methanol extraction method. In addition, the increase of temperature leads to them increased impurity observed in the HPLC profile. To further enhance the lutein recovery yield, the addition of a co-solvent in SFE is performed. Of the five solvent powders investigated, ethanol is regarded as the optimum co-solvent for use in lutein extraction. The optimum amount of ethanol to be added in the SFE operation is determined. The best lutein recovery yield obtained is 76.2% (as compared to the conventional methanol extraction method) under the conditions of 400 bar, 70℃ and with ethanol as the co-solvent being added at 0.629 ml/min.
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Chiang, Wei-Cheng, and 江偉誠. "The Autotrophical Cultivation Of Scenedesmus Obliquus In Continuous And The Optimization Of Lutein Production By Supercritical Fluid Extraction." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/28509080438702920587.
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碩士東海大學
化學工程與材料工程學系
100
Due to the depletion of energy and greenhouse effect recently, the applications of microalgae are getting important. Microalgae are organism with high growing rate, rich in fat contents and nutritional components. Also, it has great impact on water purifying. In this research, we investigate the following aspect by cultivating the microalgae: (1) Investigate the impact on the concentration of Scenedesmus obliquus and lutein content by changing the environment or the medium compositions. The result showed us that adding pressure would delay the growing of S. obliquus cells; the growing of algae could be significantly inhibited by continuous irradiating of ultraviolet UV-A; addition of phenol would inhibit the growth of algal cells; with different colors lighting experiment, culturing with white light earned the maximum concentration to S. obliquus to 2.45 g/L. As the study on the effect on lutein, illuminating ultraviolet UV-A in the last two days could increase the lutein content to 0.48%, while adding phenol and exerting pressure had less impact on lutein content. (2) Investigate the effect on the S. obliquus by cultivated by 20.0 L bio-photoreactor and continuous cultivation. The result showed that using the aeration of 0.1 vvm cultivation, the S. obliquus concentration could increase to 1.22 g/L. Apply with different aerations (vvm) do not show obvious effect on the growing of algal cells; with repeated- batch cultivation, at 0.1 vvm, under different dilution ratio for 21 days, the productivities obtain are about 0.134 g/L/day; with continuous cultivation, we study the effect of different hydraulic retention time (HRT), and in the HRT of 4.44 day, we obtain the maximum productivity, which is 0.134 g/L/day. (3) Investigate the optimal condition for extraction of lutein in S. obliquus with supercritical carbon dioxide. Applying of central composite design (CCD) to explore three factors: (a) pressure of 200 to 400 bar, (b) temperature of 40~80 ℃, (c) addition of co-solvent (ethanol) 20-50%. Results implied that, designed the experiment by response surface methodology (RSM), the largest extreme value of regression is obtained. While setting Co-solvent=50%, P=276.8 bar and T=70.1 ℃, we can obtain the lutein yield ratio up to 89.8%, compared with traditional extraction.
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van, Straaten Oliver. "Drought effects on soil carbon dioxide efflux in two ecosystems in Central Sulawesi, Indonesia." Doctoral thesis, 2010. http://hdl.handle.net/11858/00-1735-0000-0006-B136-8.
Full textBook chapters on the topic "Autotrophic production"
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Rizzetto, F., and F. L. Hooimeijer. "Reloading Landscapes: Democratic and Autotrophic Landscape of Taranto." In Regenerative Territories, 267–80. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-78536-9_17.
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AbstractCities are like “heterotrophic organisms” because they are dependent on inflows of air, water, food, matter, and energy. Unlike nature, they pollute their own habitat through the production of waste outflows and emissions, extending beyond their own footprint. Data on the ecological footprint of cities have quantified, emblematically, the imbalance between in- and outflows but also what remains: polluted air, water, and soil. The rapid growth of urbanization is a matter of serious concern, but as a part of new development, it can be turned around with an approach in which cities become an “autotrophic organism”.In 2012 Taranto, a coastal city in Southern Italy with an important commercial and military port, was declared as the city “with the highest risk of environmental crisis” in Italy due to a large industrial area developed in the proximity of a highly populated urban settlement.The cause of pollution, a steel production plant, directly employs approximately 12.000 people and another 8.000 contractors indirectly, making it Taranto’s main economic driver.The conflict between economy and environment in the city of Taranto, make it a peculiar case study to be approached with the concept of a Democratic Landscape. This concept reads the territory beyond the natural environment, also recognizing the wellbeing of the inhabitants.After the analysis of a Democratic Landscape in relation to the concept of an “autotrophic organism”, this contribution explores the transformation by regeneration of the ecosystem and the economic regime. In redeveloping a city like Taranto, changing its function from a heterotrophic organism to an autotroph organism, the approach of the so-called “linking open-loop system circularity” is more appropriate. It more adequately describes the system than what is commonly understood for circularity at the building scale of “reduce, reuse, recycle of resources”. Circularity as an attitude brings together many elements that can be considered generic for each project: it can be about recycling or reuse, cutting costs or time, and output of CO2 through reducing material inflow and the transport of materials.In the context of the Democratic Landscape and an autotropic organism, the approach of “linking open-loop system circularity” is tested on two scales in Taranto. One, on the large scale, proposing multiple reuses of agricultural crops after remediation and two, at the local scale, in rebuilding a portion of the city by reusing the demolished buildings materials.The need to rethink and redesign the flow of resources such as building materials, water, food, and energy is essential to the future sustainability of cities. It involves thinking about how to use existing resources rather than dispose of them as in the linear model. It also means establishing new economic models in order to make a sustainable city, flows of intelligent growth and the creation of an identity for a communal sense of belonging. Together, these create a democratic, autotrophic landscape that can sustain a future.
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Gu, Ji-Dong, and Yoko Katayama. "Microbiota and Biochemical Processes Involved in Biodeterioration of Cultural Heritage and Protection." In Microorganisms in the Deterioration and Preservation of Cultural Heritage, 37–58. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_2.
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AbstractThe world cultural heritage sites face new challenges for an effective protection and management because of destruction and damage initiated by both natural and anthropogenic causes. Fresh rock and sandstone surfaces of buildings are quickly colonized and covered by a layer of microorganisms, including phototrophs, lithotrophs, and heterotrophs to form a biofilm that alters the local conditions of the stone surfaces, especially under the favorable tropical climate conditions for autotrophic microorganisms and plants. Biofilms had been studied with indigenous or pure cultures of isolated microorganisms, but the selective ones that contribute to deterioration of the cultural heritage cannot be confirmed easily. Currently, high-throughput sequencing and metegenomics analyses are capable of obtaining microbial community and composition in great depth, but they also suffer from similar weakness unable to identify the culprits in the community. With these as background, this article presents a different approach by focusing on the biochemical processes and the responsible microorganisms involved to reveal the destruction processes for management and protection. Among these different functional groups of microorganisms, lichens are known as pioneering rock-decomposing microorganisms, and both sulfur-oxidizing bacteria and fungi participate in the decomposition of sandstone via sulfur cycling and initiation of salt attack of the stone afterward, resulting in defoliation and cracking of stone. Other microorganisms including ammonia-oxidizing bacteria and archaea, especially the latter, have been recently detected on sandstone monuments providing evidence on the new organisms involved in the deterioration of cultural heritage and buildings. In addition, fungi can colonize the surfaces of the matured biofilms and play a new role in the removal of them, which has a potential biotechnological application in conservation of cultural heritage. The new proposed approach by focusing the microorganisms with identified biochemical function is more productive than a description of the community composition and assembly when assessing cultural heritage biodeterioration, and this provides basic and useful information for effective protection strategies and management.
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Niizawa, Ignacio, Brenda Y. Espinaco, Susana E. Zorrilla, and Guillermo A. Sihufe. "Astaxanthin production by autotrophic cultivation of Haematococcus pluvialis: A success story." In Global Perspectives on Astaxanthin, 71–89. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-823304-7.00005-2.
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"Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity." In Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity, edited by Megan S. Sterling and Kenneth I. Ashley. American Fisheries Society, 2003. http://dx.doi.org/10.47886/9781888569445.ch17.
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<em>Abstract.</em>—A solid briquette fertilizer for use in the Pacific Northwest streams and elsewhere was identified from a variety of slow-release formulations (26 were tested with varying N:P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O ratios and binders) using indoor trough and controlled field experiments. The use of a slow-release fertilizer is an innovative method for adding inorganic nutrients to nutrientpoor (oligotrophic) streams to increase autotrophic production and aid in the restoration of salmonid populations. A series of indoor trough experiments demonstrated that the majority of samples containing binders of molasses, hydrated lime, vegetable oil, bentonite, starch, acrawax, candle wax, and Daratak® XB-3631 (unpolymerized Saran™) dissolved too slowly. The fastest dissolution rates occurred with fertilizer briquettes having no binder or vegetable oil. Further trough and field studies using fertilizer with no binder and vegetable oil as binder examined the effects of varying N:P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O ratios. Dissolution rates were varied by using different percentages of magnesium ammonium phosphate (MagAmP; its formula 7:40:0 N:P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O) and urea (46:0:0). Optimal continual nutrient release for a period of four months was achieved with a fertilizer formulation of 17:30:0 (percent by weight N:P<sub>2</sub>O<sub>5</sub>:K<sub>2</sub>O), with a ratio of 75% MagAmP to 25% urea, and containing no binder. The dissolution rate for this product ranged from 4.6% to 6.6% per week (for field and trough experiments, respectively) in water of 0.15 m/s average velocity. These studies indicate that a slow-release fertilizer product can be manufactured to last approximately four months when applied in the spring to stimulate autotrophic production in nutrient deficient streams, thereby increasing forage and salmonid production.
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Ji, Xuan, Luke Webster, Taylor J. Wass, and Peer M. Schenk. "Cultivation Techniques to Induce High-Value Nutraceuticals in Microalgae." In Algal Functional Foods and Nutraceuticals: Benefits, Opportunities, and Challenges, 29–44. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815051872122010006.
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Microalgae are unicellular autotrophic and heterotrophic microorganisms that can exceed the areal productivity of land plants by order of magnitude. Microalgae are producers of food, medicines, high-value bioactive substances and biofuels. They are highly adaptable, allowing them to thrive in freshwater and saltwater, and can be cultivated on non-arable land. Different cultivation methods have varying effects on the yield of bioactive substances produced by microalgae. As such, selecting the appropriate cultivation conditions is imperative for efficient compound production. This chapter summarizes the current state of microalgae cultivation, techniques for overproduction of high-value nutraceuticals, and future prospects, with the aim of providing the reader with fresh ideas for the cultivation of microalgae for human health.
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Culver, David C., and Tanja Pipan. "Sources of Energy in Subterranean Environments." In The Biology of Caves and Other Subterranean Habitats, 24–42. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198820765.003.0002.
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Although subterranean habitats in general and caves in particular are often held to be extremely energy-poor (oligotrophic) environments, not all are. Compared to surface habitats, subterranean habitats are nutrient-poor, especially because there is no photo-autotrophic production and chemoautotrophy appears to be uncommon. On the other hand, these differences are not always pronounced. For example, the quantities of carbon fluxes in cave streams are in the range of those reported from surface streams. In some subterranean systems, chemoautotrophy is the main source of energy, but more typically subterranean communities depend on allochthonous sources of organic carbon. The major source of carbon in interstitial habitats is Dissolved Organic Matter (DOM) from surface waters. The major sources of carbon for cave communities are (1) water percolating from the surface, (2) sinking streams that enter caves, and (3) activities of animals moving in and out of caves.
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Sapunov, Valentin. "Real Need of the World in Food." In Advances in Environmental Engineering and Green Technologies, 1–12. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1042-1.ch001.
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Mankind has minimal areas of agricultural land that produces more food than required to feed the world's population. When allocating forces and assets within the framework of the global policy of investing in agriculture, it can be safely reduced. What is food policy in the 21st century? First of all, it is advisable to increase investments in the study of food opportunities, the development of technology for the collection and processing of aborigine animals and plants in particular territories with a further increase in investments in the methods of biological technology. It is advisable to increase the investments in industrial methods for obtaining food products from animals, plants, microorganisms, in the future – in the course of chemical industrial synthesis. Vernadsky predicted that in the future, mankind will switch to autotrophic nutrition, i.e. artificial synthesis of food from inorganic materials. Biotechnology will gradually reduce the volume of traditional agricultural production.
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Irina Cordea, Mirela, and Orsolya Borsai. "Salt and Water Stress Responses in Plants." In Plant Stress Physiology - Perspectives in Agriculture [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101072.
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Climate change-driven ecological disturbances have a great impact on freshwater availability which hampers agricultural production. Currently, drought and salinity are the two major abiotic stress factors responsible for the reduction of crop yields worldwide. Increasing soil salt concentration decreases plant water uptake leading to an apparent water limitation and later to the accumulation of toxic ions in various plant organs which negatively affect plant growth. Plants are autotrophic organisms that function with simple inorganic molecules, but the underlying pathways of defense mechanisms are much more complex and harder to unravel. However, the most promising strategy to achieve sustainable agriculture and to meet the future global food demand, is the enhancement of crop stress tolerance through traditional breeding techniques and genetic engineering. Therefore, it is very important to better understand the tolerance mechanisms of the plants, including signaling pathways, biochemical and physiological responses. Although, these mechanisms are based on a well-defined set of basic responses, they can vary among different plant species.
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Bhattacharya, Ishita. "Microalgae: An Exquisite Oil Producer." In Progress in Microalgae Research - A Path for Shaping Sustainable Futures. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.104895.
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With the influx in population and shortage of conventional energy-sources, an exponential-rise of the microalgal oil-production has been observed in the past two decades. The algal bio-oil is used in various industries viz. food, pharmaceutical, cosmetic and biodiesel plants. The present study is focused towards the production of oil from oleaginous microalgae in photo-bioreactors and open water systems. Moreover, microalgae can thrive in non-cultivable waters like seawater, salt water and even wastewater which make the algal technology more attractive in terms of soil and water preservation. Using sunlight and nutrients like salts of magnesium, potassium, sodium etc. the autotrophic microalgae can grow in large quantities in indoor photo-bioreactors and in open ponds. Microalgae are able to produce approximately 10,000 gallons of oil per acre as compared to the higher plants that produces only 50 gallons per acre (soy), 110 to 145 gallons per acre (rapeseed), 175 gallons per acre (Jatropha), 650 gallons per acre (palm). The biomass productivity is 10 times higher than that of the phytoplanktons and 20–30% higher than that of the terrestrial biomass. In terms of the fatty acid composition, the microalgal oil can well match with the plant-derived oil, mainly C16 and C18 fatty acids. Some microalgae are also rich in valuable polyunsaturated-fatty-acids, which have multiple health benefits.
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N. Munubi, Renalda, and Hieromin A. Lamtane. "Animal Waste and Agro-by-Products: Valuable Resources for Producing Fish at Low Costs in Sub-Saharan Countries." In Innovation in the Food Sector Through the Valorization of Food and Agro-Food By-Products. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95057.
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Animal and crop production throughout the world generate high amounts of wastes or by-products annually that may possess added value compounds with high functionality. These wastes and by-products may cause negative environmental impacts and significant expenses if not well managed and or controlled. Much of these wastes and by-products is valuable and cheaper source of potentially functional compounds such as proteins, lipids, starch, micronutrients, bioactive compounds, and dietary fibbers. In aquaculture, feed is expensive, and the existing body of literature has shown that animal manure and its extracts can be successfully incorporated into fishpond to increase fish production at a low cost. In addition, crop residues such as rice bran, maize bran, and seed cakes are commonly used as pond inputs in small-scale aquaculture. Animal waste and crop residues are added in a fishpond that filter-feeding fish can use directly as feed, and these may form a major proportion of the detritus in the pond. These resources also stimulate the growth of phytoplankton that are rich in protein and are the basis of the food web that can support the growth of a range of herbivorous and omnivorous fish. Therefore, technically, wastes are used as direct feed, a source of minerals for autotrophic production and a source of organic matter for heterotrophic production. In this context, animal manure and crop residues have been used to provide great opportunities to improve food security. The purpose of this review is to project the potential of animal waste and agro-by-products as a sustainable alternative as aquaculture inputs to reduce poverty, malnutrition, and hunger in developing countries.
Conference papers on the topic "Autotrophic production"
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Brune, David E. "Resource Utilization in Heterotrophic Vs Autotrophic Marine Shrimp Production." In 2022 Houston, Texas July 17-20, 2022. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2022. http://dx.doi.org/10.13031/aim.202200812.
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Chikaraishi, Y. "Hydrogen Isotopic Composition of Fatty Acids, Sterols, and Phytol: Autotrophic Vs. Heterotrophic Production." In 29th International Meeting on Organic Geochemistry. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201902871.
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Beauchamp, S., J. Kerekes, and R. Tordon. "Optical Properties and Autotrophic Production in Inland Waters in Atlantic Canada With Reference to Research Diving." In OCEANS '87. IEEE, 1987. http://dx.doi.org/10.1109/oceans.1987.1160746.
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Morais, K. C. C., J. V. C. Vargas, A. B. Mariano, J. C. Ordonez, and V. Kava. "Sustainable energy via biodiesel production from autotrophic and mixotrophic growth of the microalga Phaeodactylum tricornutum in compact photobioreactors." In 2016 IEEE Conference on Technologies for Sustainability (SusTech). IEEE, 2016. http://dx.doi.org/10.1109/sustech.2016.7897177.
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Ahmadi, Vafa, and Carlos Dinamarca. "Simulation of the Effect of Local Electric Potential and Substrate Concentration on CO2 Reduction via Microbial Electrosynthesis." In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192006.
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Integrating anaerobic digestion into electrochemical reactors is an advanced technology for biomethane recovery. Imposing low electric potential between electrodes, supplies CO2, electrons, and hydronium ions from anodic oxidation of organic and/or inorganic compounds. Then, autotrophic methanogens on the cathode produce methane from CO2 and H+ by electron uptake from the cathode. However, in mixed microbial environments, acetogens produce acetate as well. These reactions can take place via two different mechanisms, DIET (direct interspecies electron transfer) or IMET (indirect mediated electron transfer). This work investigates CO2 conversion to acetate and methane in an electrochemical biofilm reactor comparing the efficiency of CO2 reduction via DIET and IMET mechanisms at hydrogen evolving potentials from -0.3 to -0.7 vs SHE. The other goal is to prove the importance of mass balance in CO2 reduction at applied voltages. Simulations are done in AQUASIM version 2.1. Simulation results depicted that higher H+ concentration at -0.7 V vs SHE can reduce more CO2 in DIET with less current generation compared to IMET. This shows DIET the more efficient mechanism. Methane production is dominant in IMET model, however higher current is needed for CO2 fixation in this mechanism. Also, biomass concentration, acetate and methane production, substrate concentration, biofilm thickness, biomass distribution in biofilm, and current density over time in both mechanisms are investigated at variant voltages and substrate concentrations. Simulations showed that at high CO2 levels in both mechanisms CO2 conversion cannot reach maximum if the voltage is not high enough to supply H+.