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1
BENEDICT, ROBERT C., TIMOTHY PARTRIDGE, DONNA WELLS, and ROBERT L. BUCHANAN. "Bacillus cereus: Aerobic Growth Kinetics." Journal of Food Protection 56, no. 3 (March 1, 1993): 211–14. http://dx.doi.org/10.4315/0362-028x-56.3.211.
Повний текст джерелаАнотація:
Three strains of Bacillus cereus were cultured in brain heart infusion medium aerobically under conditions of variable temperature (5 to 42°C), sodium chloride concentrations (0.5–5%), pH (4.5 - 7.5), and sodium nitrite concentration (0 mg/L - 200 mg/L) to simulate conditions of normal and adverse food storage. Cultures were sampled at selected times, and plate counts were used to calculate growth curves under each condition. None of the three strains grew at 5°C, but growth did occur slowly at 8°C, and was most rapid at a temperature of 37°C. Growth occurred in media without additives in all pH's examined between 8 and 42°C. Decreasing the pH and increasing levels of sodium chloride and sodium nitrite increased the lag phase and generation times of the organism.
2
Shi, Hoi-Ping, and Chi-Mei Lee. "Phosphate removal under denitrifying conditions byBrachymonassp. strain P12 andParacoccus denitrificansPP15." Canadian Journal of Microbiology 53, no. 6 (June 2007): 727–37. http://dx.doi.org/10.1139/w07-026.
Повний текст джерелаАнотація:
In this study, we used the denitrifying phosphorus-removing bacterium Brachymonas sp. strain P12 to investigate the enhanced biologic phosphorus-removal (EBPR) mechanism involved with polyhydroxybutyrate (PHB), glycogen, and phosphorus uptake in the presence of acetate under anoxic or aerobic conditions. The results showed that excess acetate concentration and aerobic cultivation can enhance PHB formation efficiency and that PHB formation might be stimulated by glycogenolysis of the cellular glycogen. The efficiency of the uptake of anoxic phosphorus was greater when PHB production was lower. The EBPR mechanism of Brachymonas sp. strain P12 for PHB, phosphorus, and glycogen was similar to the conventional anaerobic–aerobic (or anaerobic–anoxic) EBPR models, but these models were developed under anoxic or aerobic conditions only, without an anaerobic stage. The anoxic or aerobic log phase of growth is divided into two main phases: the early log phase, in which acetate and glycogen are consumed to supply enough energy and reducing power for PHB formation and cell growth (phosphorus assimilation), and the late log phase, which ends the simultaneous degradation of PHB and remaining acetate for polyphosphate accumulation. Glycogenolysis plays a significant role in the alternate responses between PHB formation and phosphorus uptake under anoxic or aerobic conditions. After the application of the denitrifying phosphorus-removing bacterium Brachymonas sp. strain P12, aerobic cultivation increases the level of PHB production, and anoxic cultivation further increases phosphorus uptake.
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Kataoka, Naoya, Alisa S. Vangnai, Thunyarat Pongtharangkul, Toshiharu Yakushi, and Kazunobu Matsushita. "Butyrate production under aerobic growth conditions by engineered Escherichia coli." Journal of Bioscience and Bioengineering 123, no. 5 (May 2017): 562–68. http://dx.doi.org/10.1016/j.jbiosc.2016.12.008.
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Arcangeli, Jean-Pierre, and Erik Arvin. "Growth of an aerobic and an anoxic toluene-degrading biofilm - a comparative study." Water Science and Technology 32, no. 8 (October 1, 1995): 125–32. http://dx.doi.org/10.2166/wst.1995.0278.
Повний текст джерелаАнотація:
The growth dynamics of a toluene-degrading biofilm was investigated under aerobic and under nitrate-reducing (anoxic) conditions. The study was performed with a continuously fed biofilm reactor (biodrum system). Under denitrifying conditions, the maximum toluene degradation in the reactor was achieved during the exponential growth phase of the biofilm. Under aerobic conditions, however, the maximum toluene degradation was reached during the lag phase of biofilm growth. Meanwhile, a simultaneous increase of the suspended biomass concentration in the bulk occurred concomitant with the toluene removal. The comparison of the structure of the aerobic and anoxic biofilms indicated that the anoxic biofilm was smooth and regular whereas the aerobic biofilm showed a lot of irregularity and a filamentous structure on top of the biofilm. Both the aerobic and the anoxic growth were modelled using the computer programme BIOSIM from EAWAG. The models considered active and inactive biomass. The active biomass was growing on toluene as sole carbon source, whereas the inactive biomass was composed of polymers and dead cells unable to degrade toluene. Model simulations showed that the biofilm activity was mainly concentrated in the top-layer of the biofilm under both aerobic and anoxic conditions.
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Liu, Wei, Shi Lei Dong, Fei Xu, Xue Qin Wang, T. Ryan Withers, Hongwei D. Yu, and Xin Wang. "Effect of Intracellular Expression of Antimicrobial Peptide LL-37 on Growth of Escherichia coli Strain TOP10 under Aerobic and Anaerobic Conditions." Antimicrobial Agents and Chemotherapy 57, no. 10 (July 15, 2013): 4707–16. http://dx.doi.org/10.1128/aac.00825-13.
Повний текст джерелаАнотація:
ABSTRACTAntimicrobial peptides (AMPs) can cause lysis of target bacteria by directly inserting themselves into the lipid bilayer. This killing mechanism confounds the identification of the intracellular targets of AMPs. To circumvent this, we used a shuttle vector containing the inducible expression of a human cathelicidin-related AMP, LL-37, to examine its effect onEscherichia coliTOP10 under aerobic and anaerobic growth conditions. Induction of LL-37 caused growth inhibition and alteration in cell morphology to a filamentous phenotype. Further examination of theE. colicell division protein FtsZ revealed that LL-37 did not interact with FtsZ. Moreover, intracellular expression of LL-37 results in the enhanced production of reactive oxygen species (ROS), causing lethal membrane depolarization under aerobic conditions. Additionally, the membrane permeability was increased after intracellular expression of LL37 under both aerobic and anaerobic conditions. Transcriptomic analysis revealed that intracellular LL-37 mainly affected the expression of genes related to energy production and carbohydrate metabolism. More specifically, genes related to oxidative phosphorylation under both aerobic and anaerobic growth conditions were affected. Collectively, our current study demonstrates that intracellular expression of LL-37 inE. colican inhibit growth under aerobic and anaerobic conditions. While we confirmed that the generation of ROS is a bactericidal mechanism for LL-37 under aerobic growth conditions, we also found that the intracellular accumulation of cationic LL-37 influences the redox and ion status of the cells under both growth conditions. These data suggest that there is a new AMP-mediated bacterial killing mechanism that targets energy metabolism.
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González-Hernández, Yusmel, Emilie Michiels, and Patrick Perré. "A Comprehensive Mechanistic Yeast Model Able to Switch Metabolism According to Growth Conditions." Fermentation 8, no. 12 (December 6, 2022): 710. http://dx.doi.org/10.3390/fermentation8120710.
Повний текст джерелаАнотація:
This paper proposes a general approach for building a mechanistic yeast model able to predict the shift of metabolic pathways. The mechanistic model accounts for the coexistence of several metabolic pathways (aerobic fermentation, glucose respiration, anaerobic fermentation and ethanol respiration) whose activation depends on growth conditions. This general approach is applied to a commercial strain of Saccharomyces cerevisiae. Stoichiometry and yeast kinetics were mostly determined from aerobic and completely anaerobic experiments. Known parameters were taken from the literature, and the remaining parameters were estimated by inverse analysis using the particle swarm optimization method. The optimized set of parameters allows the concentrations to be accurately determined over time, reporting global mean relative errors for all variables of less than 7 and 11% under completely anaerobic and aerobic conditions, respectively. Different affinities of yeast for glucose and ethanol tolerance under aerobic and anaerobic conditions were obtained. Finally, the model was successfully validated by simulating a different experiment, a batch fermentation process without gas injection, with an overall mean relative error of 7%. This model represents a useful tool for the control and optimization of yeast fermentation systems. More generally, the modeling framework proposed here is intended to be used as a building block of a digital twin of any bioproduction process.
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Malik, Muhammad, Syed Hussain, and Karl Drlica. "Effect of Anaerobic Growth on Quinolone Lethality with Escherichia coli." Antimicrobial Agents and Chemotherapy 51, no. 1 (October 16, 2006): 28–34. http://dx.doi.org/10.1128/aac.00739-06.
Повний текст джерелаАнотація:
ABSTRACT Quinolone activity against Escherichia coli was examined during aerobic growth, aerobic treatment with chloramphenicol, and anaerobic growth. Nalidixic acid, norfloxacin, ciprofloxacin, and PD161144 were lethal for cultures growing aerobically, and the bacteriostatic activity of each quinolone was unaffected by anaerobic growth. However, lethal activity was distinct for each quinolone with cells treated aerobically with chloramphenicol or grown anaerobically. Nalidixic acid failed to kill cells under both conditions; norfloxacin killed cells when they were grown anaerobically but not when they were treated with chloramphenicol; ciprofloxacin killed cells under both conditions but required higher concentrations than those required with cells grown aerobically; and PD161144, a C-8-methoxy fluoroquinolone, was equally lethal under all conditions. Following pretreatment with nalidixic acid, a shift to anaerobic conditions or the addition of chloramphenicol rapidly blocked further cell death. Formation of quinolone-gyrase-DNA complexes, observed as a sodium dodecyl sulfate (SDS)-dependent drop in cell lysate viscosity, occurred during aerobic and anaerobic growth and in the presence and in the absence of chloramphenicol. However, lethal chromosome fragmentation, detected as a drop in viscosity in the absence of SDS, occurred with nalidixic acid treatment only under aerobic conditions in the absence of chloramphenicol. With PD161144, chromosome fragmentation was detected when the cells were grown aerobically and anaerobically and in the presence and in the absence of chloramphenicol. Thus, all quinolones tested appear to form reversible bacteriostatic complexes containing broken DNA during aerobic growth, during anaerobic growth, and when protein synthesis is blocked; however, the ability to fragment chromosomes and to rapidly kill cells under these conditions depends on quinolone structure.
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Wang, Wu, Hao Huang, Guoqiang Tan, Fan Si, Min Liu, Aaron P. Landry, Jianxin Lu, and Huangen Ding. "In vivo evidence for the iron-binding activity of an iron–sulfur cluster assembly protein IscA in Escherichia coli." Biochemical Journal 432, no. 3 (November 25, 2010): 429–36. http://dx.doi.org/10.1042/bj20101507.
Повний текст джерелаАнотація:
IscA is a key member of the iron–sulfur cluster assembly machinery in prokaryotic and eukaryotic organisms; however, the physiological function of IscA still remains elusive. In the present paper we report the in vivo evidence demonstrating the iron-binding activity of IscA in Escherichia coli cells. Supplement of exogenous iron (1 μM) in M9 minimal medium is sufficient to maximize the iron binding in IscA expressed in E. coli cells under aerobic growth conditions. In contrast, IscU, an iron–sulfur cluster assembly scaffold protein, or CyaY, a bacterial frataxin homologue, fails to bind any iron in E. coli cells under the same experimental conditions. Interestingly, the strong iron-binding activity of IscA is greatly diminished in E. coli cells under anaerobic growth conditions. Additional studies reveal that oxygen in medium promotes the iron binding in IscA, and that the iron binding in IscA in turn prevents formation of biologically inaccessible ferric hydroxide under aerobic conditions. Consistent with the differential iron-binding activity of IscA under aerobic and anaerobic conditions, we find that IscA and its paralogue SufA are essential for the iron–sulfur cluster assembly in E. coli cells under aerobic growth conditions, but not under anaerobic growth conditions. The results provide in vivo evidence that IscA may act as an iron chaperone for the biogenesis of iron–sulfur clusters in E. coli cells under aerobic conditions.
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BELAY, NEGASH, and AVRAHAM RASOOLY. "Staphylococcus aureus Growth and Enterotoxin A Production in an Anaerobic Environment." Journal of Food Protection 65, no. 1 (January 1, 2002): 199–204. http://dx.doi.org/10.4315/0362-028x-65.1.199.
Повний текст джерелаАнотація:
The effects of strict anaerobic conditions on the growth of Staphylococcus aureus and the production of staphylococcal enterotoxin A (SEA) were studied. The growth of S. aureus, a facultative anaerobic bacterium, is slower anaerobically than aerobically. When grown on brain heart infusion broth at 37°C, the anaerobic generation time at mid-log phase was 80 min, compared with 35 min for the aerobic control. In contrast to previous studies demonstrating that staphylococcal cell density was 9- to 17-fold greater in aerobic than in anaerobic cultures, data for a staphylococcal strain implicated in food poisoning showed that the cell density was only two to three times as great in aerobic cultures. Production of SEA was monitored by Western immunoblotting and shown to be growth dependent. With slower anaerobic growth, relatively less toxin was produced than under aerobic conditions, but in both cases SEA was detected after 120 min of incubation. The combined effects of temperature and aeration on S. aureus were also studied. Growth and toxin production of aerobic and anaerobic cultures at temperatures ranging from 14 to 37°C were analyzed. Growth was still observed at low temperatures in both environments. A linear model for S. aureus aerobic or anaerobic growth as a function of incubation temperature was developed from these studies. The model was tested from 17 to 35.5°C, and the results suggest that the model can accurately predict the S. aureus growth rate in this temperature range. The data suggest that anaerobic conditions are not an effective barrier against S. aureus growth.
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Beranová, Jana, María C. Mansilla, Diego de Mendoza, Dana Elhottová, and Ivo Konopásek. "Differences in Cold Adaptation of Bacillus subtilis under Anaerobic and Aerobic Conditions." Journal of Bacteriology 192, no. 16 (June 25, 2010): 4164–71. http://dx.doi.org/10.1128/jb.00384-10.
Повний текст джерелаАнотація:
ABSTRACT Bacillus subtilis, which grows under aerobic conditions, employs fatty acid desaturase (Des) to fluidize its membrane when subjected to temperature downshift. Des requires molecular oxygen for its activity, and its expression is regulated by DesK-DesR, a two-component system. Transcription of des is induced by the temperature downshift and is decreased when membrane fluidity is restored. B. subtilis is also capable of anaerobic growth by nitrate or nitrite respiration. We studied the mechanism of cold adaptation in B. subtilis under anaerobic conditions that were predicted to inhibit Des activity. We found that in anaerobiosis, in contrast to aerobic growth, the induction of des expression after temperature downshift (from 37°C to 25°C) was not downregulated. However, the transfer from anaerobic to aerobic conditions rapidly restored the downregulation. Under both aerobic and anaerobic conditions, the induction of des expression was substantially reduced by the addition of external fluidizing oleic acid and was fully dependent on the DesK-DesR two-component regulatory system. Fatty acid analysis proved that there was no desaturation after des induction under anaerobic conditions despite the presence of high levels of the des protein product, which was shown by immunoblot analysis. The cold adaptation of B. subtilis in anaerobiosis is therefore mediated exclusively by the increased anteiso/iso ratio of branched-chain fatty acids and not by the temporarily increased level of unsaturated fatty acids that is typical under aerobic conditions. The degrees of membrane fluidization, as measured by diphenylhexatriene fluorescence anisotropy, were found to be similar under both aerobic and anaerobic conditions.
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DOMINGUEZ, SILVIA A., and DONALD W. SCHAFFNER. "Modeling the Growth of Salmonella in Raw Poultry Stored under Aerobic Conditions." Journal of Food Protection 71, no. 12 (December 1, 2008): 2429–35. http://dx.doi.org/10.4315/0362-028x-71.12.2429.
Повний текст джерелаАнотація:
The presence of Salmonella in raw poultry is a well-recognized risk factor for foodborne illness. The objective of this study was to develop and validate a mathematical model that predicts the growth of Salmonella in raw poultry stored under aerobic conditions at a variety of temperatures. One hundred twelve Salmonella growth rates were extracted from 12 previously published studies. These growth rates were used to develop a square-root model relating the growth rate of Salmonella to storage temperature. Model predictions were compared to growth rate measurements collected in our laboratory for four poultry-specific Salmonella strains (two antibiotic-resistant and two nonresistant strains) inoculated onto raw chicken tender-loins. Chicken was inoculated at two levels (103 CFU/cm2 and ≤ 10 CFU/cm2) and incubated at temperatures ranging from 10 to 37°C. Visual inspection of the data, bias and accuracy factors, and comparison with two other published models were used to analyze the performance of the new model. Neither antibiotic resistance nor inoculum size affected Salmonella growth rates. The presence of spoilage microflora did not appear to slow the growth of Salmonella. Our model provided intermediate predicted growth rates when compared with the two other published models. Our model predicted slightly faster growth rates than those observed in inoculated chicken in the temperature range of 10 to 28°C but slightly slower growth rates than those observed between 30 and 37°C. Slightly negative bias factors were obtained in every case (−5to −3%); however, application of the model may be considered fail-safe for storage temperatures below 28°C.
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Shirvanyan, Anahit H., Satenik N. Mirzoyan, and Karen A. Trchounian. "PECULIARITIES OF GROWTH PARAMETERS OF $SACCHAROMYCES~CEREVISIAE$ UNDER DIFFERENT CONDITIONS." Proceedings of the YSU B: Chemical and Biological Sciences 55, no. 3 (256) (December 23, 2021): 255–65. http://dx.doi.org/10.46991/pysu:b/2021.55.3.255.
Повний текст джерелаАнотація:
Saccharomyces cerevisiae is an essential component of human civilization because of its extensive use in food industry. At the point of industrial usage it is very important to get large amount of biomass but many factors causes yeast's viability loss and death. The aim of this work was to study the peculiarities of growth parameters – specific growth rate (SGR, μ, growth yield) of S. cerevisiae wine and beer strains under different external conditions, as well as pH and oxidation-reduction potential (ORP) changes during growth. It was shown that under aerobic cultivation, the conditions 30℃ and pH 6.5 are more favorable for the growth of 2 strains (ATCC 9804, μ = 0.398; ATCC 13007, μ = 0.407), where they can enhance the biomass, and under microaerobic conditions the pH 5.0 and 37℃ are more favorable (ATCC 9804, μ = 0.35; ATCC 13007, μ = 0.436). During aerobic conditions, lower ORP values are established which did not depend on growth temperature and external pH. Under microaerobic conditions until the establish¬ment of the stationary phase (24 h) pH dependent changes of ORP were established. Obtained results will help to clarify the biochemical, biophysical and bioenergetic phenomena of yeast survival that can enhance the biomass growth and yield and thus applied industrial scale.
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Nielsen, P. H., P. Roslev, T. E. Dueholm, and J. L. Nielsen. "Microthrix parvicella, a specialized lipid consumer in anaerobic–aerobic activated sludge plants." Water Science and Technology 46, no. 1-2 (July 1, 2002): 73–80. http://dx.doi.org/10.2166/wst.2002.0459.
Повний текст джерелаАнотація:
The in situ physiology of the filamentous bacterium Microthrix parvicella was investigated in anaerobic-aerobic dynamic phases in activated sludge with focus on the uptake of long chain fatty acids (LCFA) and growth. When 14C-labeled oleic acid was added to activated sludge with an excessive growth of M. parvicella, only little 14C-CO2 was produced under anaerobic conditions while a lot was produced under aerobic conditions. Microautoradiographic studies revealed that M. parvicella took up oleic acid under both anaerobic and aerobic conditions, while only a few floc formers were able to take it up under anaerobic conditions. Extraction and separation of the radioactive biomass into different lipid fractions showed that the oleic acid was stored mainly as neutral lipids under anaerobic conditions, whereas conversion to membrane phospholipids occurred almost exclusively under aerobic conditions, indicating growth. The surface properties of M. parvicella and other bacteria were characterized by hydrophobic fluorescent microspheres, which showed that M. parvicella was relatively hydrophobic. Furthermore, a surface-associated extracellular lipase activity was observed, indicating the ability of M. parvicella to degrade lipids near the filament surface. The results support the hypothesis that uptake and storage of LCFA as lipids under anaerobic conditions provide an effective competition strategy against bacteria that can only take up LCFA under aerobic conditions. Thus, M. parvicella seems to be a specialized lipid consumer with a physiological potential analogous to PAOs and GAOs being able to take up LCFA (but not short chain fatty acids or glucose) under anaerobic conditions and subsequently use the storage material for growth when nitrate or oxygen are available as electron acceptors.
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ZURERA-COSANO, G., A. M. CASTILLEJO-RODRÍGUEZ, R. M. GARCÍA-GIMENO, and F. RINCÓN-LEÓN. "Performance of Response Surface and Davey Model for Prediction of Staphylococcus aureus Growth Parameters under Different Experimental Conditions." Journal of Food Protection 67, no. 6 (June 1, 2004): 1138–45. http://dx.doi.org/10.4315/0362-028x-67.6.1138.
Повний текст джерелаАнотація:
The combined effect of different temperatures (7 to 19°C), pH levels (4.5 to 8.5), sodium chloride levels (0 to 8%), and sodium nitrite levels (0 to 200 ppm) on the predicted growth rate and lag time of Staphylococcus aureus under aerobic and anaerobic conditions was studied. The two predictive models developed, response surface (RS) and the Davey model, provided reliable estimates of the two kinetic parameters studied. The RS provided better predictions of maximum specific growth rate, with bias factors of 1.06 and 1.31 and accuracy factors of 1.17 and 1.37, respectively, in aerobic and anaerobic conditions. The Davey model performed more accurately for lag time, with a bias factor of 1.12 and an accuracy factor of 1.49, for both aerobic and anaerobic conditions. Predictive growth models are a valuable tool, enabling swift determination of Staphylococcus aureus growth rate and lag time. These data are essential for ensuring staphylococcus-relatedquality and safety of food products.
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Horntvedt, Bjarne R., Morten Rambekk, and Rune Bakke. "Oscillating conditions for influencing the composition of mixed biological cultures." Water Science and Technology 37, no. 4-5 (February 1, 1998): 259–62. http://dx.doi.org/10.2166/wst.1998.0640.
Повний текст джерелаАнотація:
This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).
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Smetanková, Jana, Zuzana Hladíková, František Valach, Michaela Zimanová, Zlatica Kohajdová, Gabriel Greif, and Mária Greifová. "Influence of aerobic and anaerobic conditions on the growth and metabolism of selected strains of Lactobacillus plantarum." Acta Chimica Slovaca 5, no. 2 (November 1, 2012): 204–10. http://dx.doi.org/10.2478/v10188-012-0031-1.
Повний текст джерелаАнотація:
Abstract Three wild strains of Lactobacillus plantarum were investigated for their growth and ability to produce lactic acid, acetic acid and ethanol under aerobic and anaerobic conditions. They were tested at three different temperatures (30 °C, 37 °C and 45 °C). The growth of lactobacilli was studied by measuring optical density (OD) at λ = 600 nm and pH value at the following times. With increasing temperature difference of cell yield was observed. The final cell yield under aerobic conditions was higher. Organic acids and ethanol were analysed using an HPLC RID method. Formation of lactic acid (as the major metabolite) was the slowest during cultivation at 30 °C, but the final amount of lactic acid showed the highest values. Concentrations of metabolites produced by lactobacilli after 48th hours of cultivation were: 9.18-11.48 g.dm-3 (lactic acid), 0.84-1.65 g.dm-3 (acetic acid) and 2.51-4.03 g.dm-3 (ethanol). No significant differences (p = 0.05) were found in production of lactic acid and ethanol by different bacterial strains under aerobic and anaerobic conditions. Statistically significant differences (p = 0.05) were observed in production of acetic acid by 2L2 under aerobic and anaerobic conditions and for production of ethanol under anaerobic conditions by strains 1L5 and 2L2.
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STREUFERT, RACHEL K., SUSANNE E. KELLER, and JOELLE K. SALAZAR. "Relationship of Growth Conditions to Desiccation Tolerance of Salmonella enterica, Escherichia coli, and Listeria monocytogenes." Journal of Food Protection 84, no. 8 (April 14, 2021): 1380–84. http://dx.doi.org/10.4315/jfp-21-077.
Повний текст джерелаАнотація:
ABSTRACT Growth on solid media as sessile cells is believed to increase the desiccation tolerance of Salmonella enterica. However, the reasons behind increased resistance have not been well explored. In addition, the same effect has not been examined for other foodborne pathogens such as pathogenic Escherichia coli or Listeria monocytogenes. The purpose of this research was twofold: first, to determine the role of oxygenation during growth on the desiccation resistance of S. enterica, E. coli, and L. monocytogenes, and second, to determine the effect of sessile versus planktonic growth on the desiccation resistance of these pathogens. Three different serotypes each of Salmonella, E. coli, and L. monocytogenes were cultured in Trypticase soy broth with 0.6% yeast extract (TSBYE), with (aerobic) shaking or on TSBYE with agar under either aerobic or anaerobic conditions and harvested in the stationary phase. After adding cell suspensions to cellulose filter disks, pathogen survival was determined by enumeration before drying (0 h) and after drying for 24 h. Results showed statistical differences in harvested initial populations before drying. For Salmonella, a correlation was found between high initial population and greater survival on desiccation (P = 0.05). In addition, statistical differences (P ≤ 0.05) between survival based on growth type were identified. However, differences found were not the same for the three pathogens, or between their serotypes. In general, Salmonella and E. coli desiccation resistance followed the pattern of aerobic agar media ≥ liquid media ≥ anaerobic agar media. For L. monocytogenes serotypes, resistance to desiccation was not statistically different based on mode of growth. These results indicate growth on solid media under aerobic conditions is not always necessary for optimal desiccation survival, but may be beneficial when the desiccation resistance of the test serotype is unknown. HIGHLIGHTS
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Najafpour, Ghasem D., Marjan Khorrami, Habibollah Younesi, and Maryam N. Hosseinpour. "BIODEMINERALIZATION OF SHRIMP SHELL VIA AEROBIC AND ANAEROBIC CONDITIONS: GROWTH KINETIC STUDIES." Environmental Engineering and Management Journal 14, no. 4 (2015): 731–36. http://dx.doi.org/10.30638/eemj.2015.081.
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Siavoshi, Farideh, Parastoo Saniee, Mojgan Atabakhsh, Shahrzad Pedramnia, Atefeh Tavakolian, and Masoumeh Mirzaei. "Mucoid Helicobacter pylori Isolates with Fast Growth under Microaerobic and Aerobic Conditions." Helicobacter 17, no. 1 (January 3, 2012): 62–67. http://dx.doi.org/10.1111/j.1523-5378.2011.00913.x.
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Bernard, Clément, Virginie Lemoine, Michel A. Hoogenkamp, Marion Girardot, Bastiaan P. Krom, and Christine Imbert. "Candida albicans enhances initial biofilm growth of Cutibacterium acnes under aerobic conditions." Biofouling 35, no. 3 (March 16, 2019): 350–60. http://dx.doi.org/10.1080/08927014.2019.1608966.
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Ali, Muhamad, Melinda Sanggu Artha, Muhamad Aidil Fadjar Suryadi, Djoko Kisworo, and Muhamad Amin. "The Growth and Bacteriocin Productions of Enterococcus Faecium Cultured in Aerobic and Anaerobic Conditions." IOP Conference Series: Earth and Environmental Science 1036, no. 1 (July 1, 2022): 012063. http://dx.doi.org/10.1088/1755-1315/1036/1/012063.
Повний текст джерелаАнотація:
Abstract Bacteriocins are antimicrobial compounds produced by diverse members of lactic acid bacteria (LAB). Bacteriocins can be used as food bio preservatives to increase the shelf life of food naturally by preventing or killing foodborne pathogens. One of the lactic acid bacteria that produce bacteriocin is Enterococcus faecium. Some LAB grown on semi-synthetic complex media such as MRS (de Mann Rogosa Sharpe) can make a high population of bacterial cells and relatively large bacteriocins. This study aimed to observe the growth of E. faecium on MRS and LB media under aerobic and anaerobic conditions. Cultures were performed for 4.5h, 5h, 5.5h, 6h, 6.5h, and 7h. The amount of bacteriocin produced was investigated by SDS-PAGE. Meanwhile, the inhibitory activity was measured against Listeria monocytogenes (LM). The results showed that E. faecium grew better in deMan Rogosa Sharp (MRS) medium under anaerobic conditions than in MRS medium under aerobic conditions as well as Luria Bertani (LB) media under aerobic and anaerobic conditions. The SDS-PAGE results showed a protein band measuring about 90 kDa, which was thought to be a bacteriocin. The inhibition test showed a clear zone in the LM culture, which indicated that the bacteria produced bacteriocins that could inhibit the growth of pathogenic bacteria.
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ter Linde, J. J. M., H. Liang, R. W. Davis, H. Y. Steensma, J. P. van Dijken, and J. T. Pronk. "Genome-Wide Transcriptional Analysis of Aerobic and Anaerobic Chemostat Cultures of Saccharomyces cerevisiae." Journal of Bacteriology 181, no. 24 (December 15, 1999): 7409–13. http://dx.doi.org/10.1128/jb.181.24.7409-7413.1999.
Повний текст джерелаАнотація:
ABSTRACT The yeast Saccharomyces cerevisiae is unique among eukaryotes in exhibiting fast growth in both the presence and the complete absence of oxygen. Genome-wide transcriptional adaptation to aerobiosis and anaerobiosis was studied in assays using DNA microarrays. This technique was combined with chemostat cultivation, which allows controlled variation of a single growth parameter under defined conditions and at a fixed specific growth rate. Of the 6,171 open reading frames investigated, 5,738 (93%) yielded detectable transcript levels under either aerobic or anaerobic conditions; 140 genes showed a >3-fold-higher transcription level under anaerobic conditions. Under aerobic conditions, transcript levels of 219 genes were >3-fold higher than under anaerobic conditions.
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Wang, James C., Joehassin Cordero, Yan Sun, Mayank Aranke, Randall Wolcott, Jane A. Colmer-Hamood, and Abdul N. Hamood. "Planktonic Growth ofPseudomonas aeruginosaaround a Dual-Species Biofilm Supports the Growth ofFusobacterium nucleatumwithin That Biofilm." International Journal of Otolaryngology 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/3037191.
Повний текст джерелаАнотація:
Purpose.The goal of this study was to understand the potential interaction betweenPseudomonas aeruginosaandFusobacterium nucleatumwithin the middle ear.Methods.We examined the microbiota of ear fluid and tympanostomy tubes (TTs) obtained from patients with posttympanostomy tube otorrhea. We also examined biofilms formed byP. aeruginosaandF. nucleatum, singly or together, under aerobic or anaerobic conditions.Results.While the facultative anaerobeP. aeruginosadominated the bacterial population within the ear fluid, strict anaerobes, includingF. nucleatum,dominated bacterial populations within the TTs.F. nucleatumwas able to grow under aerobic conditions only in the presence ofP. aeruginosa, whose growth reduced the level of dissolved oxygen within the broth to nearly anoxic condition within 4 h after inoculation. The presence ofP. aeruginosaallowedF. nucleatumto maintain its growth for 72 h within the dual-species biofilm but not within the planktonic growth. Visualization of the biofilms revealed coaggregation ofP. aeruginosaandF. nucleatum.Conclusion.Extrapolation of these results suggests that, within the middle ear fluid, the growth ofP. aeruginosaproduces the anaerobic conditions required for the growth ofF. nucleatum, both within effusion and within biofilms.
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Liu, Zihe, Tobias Österlund, Jin Hou, Dina Petranovic та Jens Nielsen. "Anaerobic α-Amylase Production and Secretion with Fumarate as the Final Electron Acceptor in Saccharomyces cerevisiae". Applied and Environmental Microbiology 79, № 9 (22 лютого 2013): 2962–67. http://dx.doi.org/10.1128/aem.03207-12.
Повний текст джерелаАнотація:
ABSTRACTIn this study, we focus on production of heterologous α-amylase in the yeastSaccharomyces cerevisiaeunder anaerobic conditions. We compare the metabolic fluxes and transcriptional regulation under aerobic and anaerobic conditions, with the objective of identifying the final electron acceptor for protein folding under anaerobic conditions. We find that yeast produces more amylase under anaerobic conditions than under aerobic conditions, and we propose a model for electron transfer under anaerobic conditions. According to our model, during protein folding the electrons from the endoplasmic reticulum are transferred to fumarate as the final electron acceptor. This model is supported by findings that the addition of fumarate under anaerobic (but not aerobic) conditions improves cell growth, specifically in the α-amylase-producing strain, in which it is not used as a carbon source. Our results provide a model for the molecular mechanism of anaerobic protein secretion using fumarate as the final electron acceptor, which may allow for further engineering of yeast for improved protein secretion under anaerobic growth conditions.
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Majone, M., P. Massanisso, and R. Ramadori. "Comparison of carbon storage under aerobic and anoxic conditions." Water Science and Technology 38, no. 8-9 (October 1, 1998): 77–84. http://dx.doi.org/10.2166/wst.1998.0793.
Повний текст джерелаАнотація:
In various activated sludge systems, the biomass grows under transient (unbalanced) conditions and the storage response (formation of internal polymers as the fastest adaptation to the changing environment) becomes important. Till now the role of storage on population dynamics has been deeply investigated under anaerobic (EBPR processes) or aerobic (bulking control) conditions. Little attention has been given to processes including anoxic conditions even though in many of them storage phenomena are likely to occur (anoxic selectors, nitrogen removal processes with addition of an external source of readily biodegradable COD or with aerobic contact/anoxic stabilization). For these reasons, the aim of the present work was to investigate storage and succeeding use of stored products under anoxic and mixed (anoxic/aerobic) conditions. Batch experiments have shown that a mixed culture selected under aerobic conditions and intermittent feed (acetate-limited medium), was also able to take up acetate (90–100 mgCOD/gCOD h) and store it as PHB (35–40 mgCOD/gCOD h) under anoxic conditions. After acetate depletion, the stored PHB was used for growth and maintenance. The NUR on acetate in the presence of storage was 20 mgN/gVSS h (which corresponded to a COD removal of 6.9 mgCOD/mgN) while it dropped to 10–3 mgN/gVSS h in the “endogenous phase” when denitrification was on the stored PHB. The presence of aerobic conditions instead of anoxic ones had a major positive effect on the rate and yield of PHB storage while it had only a minor effect on the rate of PHB consumption. The latter observation can be explained by assuming that the hydrolysis of the stored product is the rate limiting step of the “endogenous” metabolism and that the hydrolysis rate is not highly dependent on aerobic-anoxic conditions. Cross-comparison of PHB storage and consumption under aerobic/anoxic conditions made it possible to determine that, in the particular mixed culture under investigation, all aerobic heterotrophs able to store were also able to denitrify.
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Thunberg, Richard L., Alan J. Sexstone, Joseph P. Calabrese, and Gary K. Bissonnette. "Effects of antecedent fermentative and respiratory growth on the detection of chloramine-stressed Escherichia coli and Salmonella typhimurium." Canadian Journal of Microbiology 47, no. 8 (August 1, 2001): 777–81. http://dx.doi.org/10.1139/w01-077.
Повний текст джерелаАнотація:
In vitro laboratory studies were performed to assess the effects of antecedent growth conditions on the recovery of Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028 following chloramine disinfection. Six- and 18-h cultures of each organism were grown under aerobic, fermentative, and nitrate-reducing conditions prior to disinfection. At predetermined time intervals during a 10-min exposure to chloramine, survivors were surface plated on nonselective recovery media to determine Cnt values. It was observed that nitrate-reducing growth predisposed the test organisms towards an increased sensitivity to chloramine stress over cells grown under fermentation or aerobic conditions (p < 0.01).Key words: Escherichia coli, Salmonella typhimurium, chloramine, survival, antecedent growth conditions.
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Karahan, Ozlem, Derin Orhon, and Mark C. M. van Loosdrecht. "Simultaneous storage and utilization of polyhydroxyalkanoates and glycogen under aerobic conditions." Water Science and Technology 58, no. 4 (September 1, 2008): 945–51. http://dx.doi.org/10.2166/wst.2008.403.
Повний текст джерелаАнотація:
This study aims to investigate the storage response of an activated sludge system in the presence of two different substrates which are stored as two different polymers. The objective of the study was to determine the changes in the response of an activated sludge system when two different storage mechanisms could occur simultaneously. Acetic acid (HAc) and soluble starch (SolS) were selected as model substrates and three different feeding conditions, namely (i) when both HAc and SolS were initially present in the reactor, (ii) only HAc was present, and (iii) only SolS was present in the substrate solution. The batch reactors were monitored for acetic acid, polyhydroxyalkanoates (PHA), poly-glucose (glycogen like substances) and oxygen uptake rate (OUR). The experiments have shown that, while the main portion of hydrolyzed starch was stored as poly-glucose, which was further used for heterotrophic growth, the rest was utilized for direct growth. However, acetic acid was totally stored as PHA and the stored PHA was used for biomass growth under the presented experimental conditions. When the system was fed with the substrate mixture, the storage mechanism was not significantly affected. Both PHA and poly-glucose storage took place simultaneously with the same stoichiometry and kinetics defined for single substrate utilization.
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Almeida, M. C., D. Butler, and J. W. Davies. "Modelling in-sewer changes in wastewater quality under aerobic conditions." Water Science and Technology 39, no. 9 (May 1, 1999): 63–71. http://dx.doi.org/10.2166/wst.1999.0443.
Повний текст джерелаАнотація:
In the present paper a model for the simulation of in-sewer transformation processes occurring during the transport of wastewater under aerobic conditions is presented. The basic approach is to use a detailed description of the transport processes to separate the effect of advection-dispersion in the variations of concentration (of a certain pollutant in a certain pipe length) from those due to transformation processes. The focus is on dry weather flow and free surface flows. Processes such as reaeration, heterotrophic growth and decay, hydrolysis, ammonification and biofilm consumption of substrate and oxygen are considered. Transformation processes are modelled using a similar approach to that of the IAWQ Activated sludge model n°1. Results of tracer experiments are presented showing the relevance of dispersion in pipe flow. The results of sensitivity analysis on the model parameters are presented. The model results are especially sensitive to variations in yield and maximum growth rate for heterotrophs. Thus, these parameters should be determined experimentally for a given system. Less precise estimates for the other parameters have less impact on the model results. This aspect is especially relevant due to the lack of established methods for the estimation of these parameters for sewer systems modelling.
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Sorokin, Dimitry Yu, Tatjana P. Tourova, Olga L. Kovaleva, J. Gijs Kuenen, and Gerard Muyzer. "Aerobic carboxydotrophy under extremely haloalkaline conditions in Alkalispirillum/Alkalilimnicola strains isolated from soda lakes." Microbiology 156, no. 3 (March 1, 2010): 819–27. http://dx.doi.org/10.1099/mic.0.033712-0.
Повний текст джерелаАнотація:
Aerobic enrichments from soda lake sediments with CO as the only substrate resulted in the isolation of five bacterial strains capable of autotrophic growth with CO at extremely high pH and salinity. The strains belonged to the Alkalispirillum/Alkalilimnicola cluster in the Gammaproteobacteria, where the ability to oxidize CO, but not growth with CO, has been demonstrated previously. The growth with CO was possible only at an oxygen concentration below 5 % and CO concentration below 20 % in the gas phase. The isolates were also capable of growth with formate but not with H2. The carboxydotrophic growth occurred within a narrow pH range from 8 to 10.5 (optimum at 9.5) and a broad salt concentration from0.3 to 3.5 M total Na+ (optimum at 1.0 M). Cells grown on CO had high respiration activity with CO and formate, while the cells grown on formate actively oxidized formate alone. In CO-grown cells, CO-dehydrogenase (CODH) activity was detectable both in soluble and membrane fractions, while the NAD-independent formate dehydrogenase (FDH) resided solely in membranes. The results of total protein profiling and the failure to detect CODH with conventional primers for the coxL gene indicated that the CO-oxidizing enzyme in haloalkaliphilic isolates might differ from the classical aerobic CODH complex. A single cbbL gene encoding the RuBisCO large subunit was detected in all strains, suggesting the presence of the Calvin cycle of inorganic carbon fixation. Overall, these results demonstrated the possibility of aerobic carboxydotrophy under extremely haloalkaline conditions.
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Amo, Taku, Maria Luz F. Paje, Akiko Inagaki, Satoshi Ezaki, Haruyuki Atomi, and Tadayuki Imanaka. "Pyrobaculum calidifontissp. nov., a novel hyperthermophilic archaeon that grows in atmospheric air." Archaea 1, no. 2 (2002): 113–21. http://dx.doi.org/10.1155/2002/616075.
Повний текст джерелаАнотація:
A novel, facultatively aerobic, heterotrophic hyperthermophilic archaeon was isolated from a terrestrial hot spring in the Philippines. Cells of the new isolate, strain VA1, were rod-shaped with a length of 1.5 to 10 μm and a width of 0.5 to 1.0 μm. Isolate VA1 grew optimally at 90 to 95 °C and pH 7.0 under atmospheric air. Oxygen served as a final electron acceptor under aerobic growth conditions, and vigorous shaking of the medium significantly enhanced growth. Elemental sulfur inhibited cell growth under aerobic growth conditions, whereas thiosulfate stimulated cell growth. Under anaerobic growth conditions, nitrate served as a final electron acceptor, but nitrite or sulfur-containing compounds such as elemental sulfur, thiosulfate, sulfate and sulfite could not act as final electron acceptors. The G+C content of the genomic DNA was 51 mol%. Phylogenetic analysis based on 16S rRNA sequences indicated that strain VA1 exhibited close relationships to species of the genusPyrobaculum. A DNA–DNA hybridization study revealed a low level of similarity (≤ 18%) between strain VA1 and previously described members of the genusPyrobaculum. Physiological characteristics also indicated that strain VA1 was distinct from thesePyrobaculumspecies. Our results indicate that isolate VA1 represents a novel species, namedPyrobaculum calidifontis.
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Freedman, David L., Meghna Swamy, Nathan C. Bell, and Mathew F. Verce. "Biodegradation of Chloromethane by Pseudomonas aeruginosa Strain NB1 under Nitrate-Reducing and Aerobic Conditions." Applied and Environmental Microbiology 70, no. 8 (August 2004): 4629–34. http://dx.doi.org/10.1128/aem.70.8.4629-4634.2004.
Повний текст джерелаАнотація:
ABSTRACT Pseudomonas aeruginosa strain NB1 uses chloromethane (CM) as its sole source of carbon and energy under nitrate-reducing and aerobic conditions. The observed yield of NB1 was 0.20 (±0.06) (mean ± standard deviation) and 0.28 (±0.01) mg of total suspended solids (TSS) mg of CM−1 under anoxic and aerobic conditions, respectively. The stoichiometry of nitrate consumption was 0.75 (±0.10) electron equivalents (eeq) of NO3 − per eeq of CM, which is consistent with the yield when it is expressed on an eeq basis. Nitrate was stoichiometrically converted to dinitrogen (0.51 ± 0.05 mol of N2 per mol of NO3 −). The stoichiometry of oxygen use with CM (0.85 ± 0.21 eeq of O2 per eeq of CM) was also consistent with the aerobic yield. Stoichiometric release of chloride and minimal accumulation of soluble metabolic products (measured as chemical oxygen demand) following CM consumption, under anoxic and aerobic conditions, indicated complete biodegradation of CM. Acetylene did not inhibit CM use under aerobic conditions, implying that a monooxygenase was not involved in initiating aerobic CM metabolism. Under anoxic conditions, the maximum specific CM utilization rate (k) for NB1 was 5.01 (±0.06) μmol of CM mg of TSS−1 day−1, the maximum specific growth rate (μmax) was 0.0506 day−1, and the Monod half-saturation coefficient (Ks ) was 0.067 (±0.004) μM. Under aerobic conditions, the values for k, μ max , and Ks were 10.7 (±0.11) μmol of CM mg of TSS−1 day−1, 0.145 day−1, and 0.93 (±0.042) μM, respectively, indicating that NB1 used CM faster under aerobic conditions. Strain NB1 also grew on methanol, ethanol, and acetate under denitrifying and aerobic conditions, but not on methane, formate, or dichloromethane.
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Narwal, Ekta, Annapurna Kannepalli, Jairam Choudhary, Yudh Vir Singh, and Maulin P. Shah. "Bioprospecting plant growth‐promoting rhizobacteria from rice genotypes and their influence on growth under aerobic conditions." Journal of Basic Microbiology 62, no. 2 (November 29, 2021): 135–49. http://dx.doi.org/10.1002/jobm.202100463.
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Shearer, Neil, Andrew P. Hinsley, Rob J. M. Van Spanning, and Stephen Spiro. "Anaerobic Growth of Paracoccus denitrificans Requires Cobalamin: Characterization ofcobK and cobJ Genes." Journal of Bacteriology 181, no. 22 (November 15, 1999): 6907–13. http://dx.doi.org/10.1128/jb.181.22.6907-6913.1999.
Повний текст джерелаАнотація:
ABSTRACT A pleiotropic mutant of Paracoccus denitrificans, which has a severe defect that affects its anaerobic growth when either nitrate, nitrite, or nitrous oxide is used as the terminal electron acceptor and which is also unable to use ethanolamine as a carbon and energy source for aerobic growth, was isolated. This phenotype of the mutant is expressed only during growth on minimal media and can be reversed by addition of cobalamin (vitamin B12) or cobinamide to the media or by growth on rich media. Sequence analysis revealed the mutation causing this phenotype to be in a gene homologous to cobK of Pseudomonas denitrificans, which encodes precorrin-6x reductase of the cobalamin biosynthesis pathway. Convergently transcribed with cobK is a gene homologous tocobJ of Pseudomonas denitrificans, which encodes precorrin-3b methyltransferase. The inability of the cobalamin auxotroph to grow aerobically on ethanolamine implies that wild-typeP. denitrificans (which can grow on ethanolamine) expresses a cobalamin-dependent ethanolamine ammonia lyase and that this organism synthesizes cobalamin under both aerobic and anaerobic growth conditions. Comparison of the cobK and cobJgenes with their orthologues suggests that P. denitrificansuses the aerobic pathway for cobalamin synthesis. It is paradoxical that under anaerobic growth conditions, P. denitrificansappears to use the aerobic (oxygen-requiring) pathway for cobalamin synthesis. Anaerobic growth of the cobalamin auxotroph could be restored by the addition of deoxyribonucleosides to minimal media. These observations provide evidence that P. denitrificansexpresses a cobalamin-dependent ribonucleotide reductase, which is essential for growth only under anaerobic conditions.
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Willows, Robert D., Vanessa Lake, Thomas Hugh Roberts, and Samuel I. Beale. "Inactivation of Mg Chelatase during Transition from Anaerobic to Aerobic Growth in Rhodobacter capsulatus." Journal of Bacteriology 185, no. 11 (June 1, 2003): 3249–58. http://dx.doi.org/10.1128/jb.185.11.3249-3258.2003.
Повний текст джерелаАнотація:
ABSTRACT The facultative photosynthetic bacterium Rhodobacter capsulatus can adapt from an anaerobic photosynthetic mode of growth to aerobic heterotrophic metabolism. As this adaptation occurs, the cells must rapidly halt bacteriochlorophyll synthesis to prevent phototoxic tetrapyrroles from accumulating, while still allowing heme synthesis to continue. A likely control point is Mg chelatase, the enzyme that diverts protoporphyrin IX from heme biosynthesis toward the bacteriochlorophyll biosynthetic pathway by inserting Mg2+ to form Mg-protoporphyrin IX. Mg chelatase is composed of three subunits that are encoded by the bchI, bchD, and bchH genes in R. capsulatus. We report that BchH is the rate-limiting component of Mg chelatase activity in cell extracts. BchH binds protoporphyrin IX, and BchH that has been expressed and purified from Escherichia coli is red in color due to the bound protoporphyrin IX. Recombinant BchH is rapidly inactivated by light in the presence of O2, and the inactivation results in the formation of a covalent adduct between the protein and the bound protoporphyrin IX. When photosynthetically growing R. capsulatus cells are transferred to aerobic conditions, Mg chelatase is rapidly inactivated, and BchH is the component that is most rapidly inactivated in vivo when cells are exposed to aerobic conditions. The light- and O2-stimulated inactivation of BchH could account for the rapid inactivation of Mg chelatase in vivo and provide a mechanism for inhibiting the synthesis of bacteriochlorophyll during adaptation of photosynthetically grown cells to aerobic conditions while still allowing heme synthesis to occur for aerobic respiration.
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Kłosowski, Grzegorz, and Dawid Mikulski. "Impact of Lignocellulose Pretreatment By-Products on S. cerevisiae Strain Ethanol Red Metabolism during Aerobic and An-aerobic Growth." Molecules 26, no. 4 (February 4, 2021): 806. http://dx.doi.org/10.3390/molecules26040806.
Повний текст джерелаАнотація:
Understanding the specific response of yeast cells to environmental stress factors is the starting point for selecting the conditions of adaptive culture in order to obtain a yeast line with increased resistance to a given stress factor. The aim of the study was to evaluate the specific cellular response of Saccharomyces cerevisiae strain Ethanol Red to stress caused by toxic by-products generated during the pretreatment of lignocellulose, such as levulinic acid, 5-hydroxymethylfurfural, furfural, ferulic acid, syringaldehyde and vanillin. The presence of 5-hydroxymethylfurfural at the highest analyzed concentration (5704.8 ± 249.3 mg/L) under aerobic conditions induced the overproduction of ergosterol and trehalose. On the other hand, under anaerobic conditions (during the alcoholic fermentation), a decrease in the biosynthesis of these environmental stress indicators was observed. The tested yeast strain was able to completely metabolize 5-hydroxymethylfurfural, furfural, syringaldehyde and vanillin, both under aerobic and anaerobic conditions. Yeast cells reacted to the presence of furan aldehydes by overproducing Hsp60 involved in the control of intracellular protein folding. The results may be helpful in optimizing the process parameters of second-generation ethanol production, in order to reduce the formation and toxic effects of fermentation inhibitors.
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Sun, Ji-Lu, Shao-Kang Zhang, Jing-Yu Chen, and Bei-Zhong Han. "Metabolic profiling of Staphylococcus aureus cultivated under aerobic and anaerobic conditions with 1H NMR-based nontargeted analysis." Canadian Journal of Microbiology 58, no. 6 (June 2012): 709–18. http://dx.doi.org/10.1139/w2012-046.
Повний текст джерелаАнотація:
Staphylococcus aureus is a major pathogen in the medical area and food-producing sector. Detailed analyses of its basic cell physiology will help comprehensively understand this pathogen, which will be useful for developing novel diagnostic and treatment tools. Oxygen is one of the most crucial growth-limiting factors for S. aureus. In this study, to characterize and distinguish metabolic profiles of S. aureus cultivated under aerobic and anaerobic conditions, nontargeted analyses of both types of cultures were carried out using 1H nuclear magnetic resonance spectroscopy. Fifty compounds were identified by Chenomx software. Characteristics of metabolic profiles were achieved by using principal components analysis. During aerobic growth, S. aureus mainly consumed glucose, alanine, arginine, glycine, isoleucine, leucine, phenylalanine, and acetate. Meanwhile, it accumulated 17 metabolites, mainly 2-oxoglutarate, isobutyrate, isovalerate, succinate, and ethanol. Under anaerobic condition, S. aureus mainly consumed glucose, arginine, and threonine. Meanwhile, it accumulated 13 metabolites, mainly ethanol, lactate, and ornithine. The representative metabolites that could most significantly differentiate metabolic profiles of S. aureus were isobutyrate, isovalerate, and succinate in aerobic cultivation; and lactate, ethanol, and ornithine in anaerobic cultivation. Among these metabolites, isobutyrate and ornithine were present only in aerobic and anaerobic culture, respectively.
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Tan, Guoqiang, Jianxin Lu, Jacob P. Bitoun, Hao Huang, and Huangen Ding. "IscA/SufA paralogues are required for the [4Fe-4S] cluster assembly in enzymes of multiple physiological pathways in Escherichia coli under aerobic growth conditions." Biochemical Journal 420, no. 3 (May 27, 2009): 463–72. http://dx.doi.org/10.1042/bj20090206.
Повний текст джерелаАнотація:
IscA/SufA paralogues are the members of the iron-sulfur cluster assembly machinery in Escherichia coli. Whereas deletion of either IscA or SufA has only a mild effect on cell growth, deletion of both IscA and SufA results in a null-growth phenotype in minimal medium under aerobic growth conditions. Here we report that cell growth of the iscA/sufA double mutant (E. coli strain in which both iscA and sufA had been in-frame-deleted) can be partially restored by supplementing with BCAAs (branched-chain amino acids) and thiamin. We further demonstrate that deletion of IscA/SufA paralogues blocks the [4Fe-4S] cluster assembly in IlvD (dihydroxyacid dehydratase) of the BCAA biosynthetic pathway in E. coli cells under aerobic conditions and that addition of the iron-bound IscA/SufA efficiently promotes the [4Fe-4S] cluster assembly in IlvD and restores the enzyme activity in vitro, suggesting that IscA/SufA may act as an iron donor for the [4Fe-4S] cluster assembly under aerobic conditions. Additional studies reveal that IscA/SufA are also required for the [4Fe-4S] cluster assembly in enzyme ThiC of the thiamin-biosynthetic pathway, aconitase B of the citrate acid cycle and endonuclease III of the DNA-base-excision-repair pathway in E. coli under aerobic conditions. Nevertheless, deletion of IscA/SufA does not significantly affect the [2Fe-2S] cluster assembly in the redox transcription factor SoxR, ferredoxin and the siderophore-iron reductase FhuF. The results suggest that the biogenesis of the [4Fe-4S] clusters and the [2Fe-2S] clusters may have distinct pathways and that IscA/SufA paralogues are essential for the [4Fe-4S] cluster assembly, but are dispensable for the [2Fe-2S] cluster assembly in E. coli under aerobic conditions.
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Bravo, Guillermo, Paulina Vega-Celedón, Juan Carlos Gentina, and Michael Seeger. "Effects of Mercury II on Cupriavidus metallidurans Strain MSR33 during Mercury Bioremediation under Aerobic and Anaerobic Conditions." Processes 8, no. 8 (July 25, 2020): 893. http://dx.doi.org/10.3390/pr8080893.
Повний текст джерелаАнотація:
Mercury is a toxic element that harms organisms and disturbs biogeochemical cycles. Mercury bioremediation is based on the reduction of Hg (II) to Hg (0) by mercury-resistant bacteria. Cupriavidus metallidurans MSR33 possesses a broad-spectrum mercury resistance. This study aims to establish the effects of mercury on growth, oxygen uptake, and mercury removal parameters by C. metallidurans MSR33 in aqueous solution during aerobic and anaerobic mercury bioremediation. A new culture medium (GBC) was designed. The effects of mercury (II) (20 ppm) on growth parameters, oxygen uptake, and mercury removal were evaluated in GBC medium in a bioreactor (3 L) under aerobiosis. The anaerobic kinetics of mercury removal was evaluated by nitrogen replacement during mercury bioremediation in a bioreactor. Strain MSR33 reached a growth rate of µ = 0.43 h−1 in the bioreactor. Mercury inhibited oxygen uptake and bacterial growth; however, this inhibition was reversed after 5 h. Strain MSR33 was able to reduce Hg (II) under aerobic and anaerobic conditions, reaching, at 24 h, a metal removal of 97% and 71%, respectively. Therefore, oxygen was crucial for efficient mercury removal by this bacterium. Strain MSR33 was capable of tolerating the toxic effects of mercury (II) during aerobic bioremediation and recovered its metabolic activity.
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Mijaylova-Nacheva, P., E. Ramírez-Camperos, and S. Cuevas-Velasco. "Treatment of organic synthesis wastewater using anaerobic packed bed and aerobic suspended growth bioreactors." Water Science and Technology 55, no. 7 (April 1, 2007): 235–43. http://dx.doi.org/10.2166/wst.2007.150.
Повний текст джерелаАнотація:
The performance of an anaerobic mesophilic packed bed reactor, with a mixture of GAC and tezontle, followed by an aerobic suspended growth system was studied for the treatment of organic chemical wastewater with a high COD concentration (22–29 g/L). The testing of the anaerobic–aerobic system was conducted in an experimental set-up for almost 2.5 years. Different operational conditions were evaluated. The anaerobic reactor showed performance stability and COD removals higher than 80% were obtained with loads up to 16.6 kg.m−3.d−1. The acclimation of the aerobic biomass to the substrate in the anaerobic effluent was very quick and COD removals higher than 94% were obtained even at high organic loads. The combined anaerobic–aerobic system allowed total COD removals higher than 99.5% and the accomplishment of the discharge requirements of 200 mgCOD/L when the anaerobic reactor was operated with loads of 8–11 kg.m−3.d−1 and the aerobic reactor with 0.33 kg.kg−1.d−1, being the total HRT of 4.4. The average TKN removal in the anaerobic–aerobic system was 97%, the average for the anaerobic reactor being 52% and that one for the aerobic system being 94%.
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Loo, C. Y., K. Mitrakul, S. Jaafar, C. Gyurko, C. V. Hughes, and N. Ganeshkumar. "Role of a nosX Homolog in Streptococcus gordonii in Aerobic Growth and Biofilm Formation." Journal of Bacteriology 186, no. 24 (December 15, 2004): 8193–206. http://dx.doi.org/10.1128/jb.186.24.8193-8206.2004.
Повний текст джерелаАнотація:
ABSTRACT Oral streptococci such as Streptococcus gordonii are facultative anaerobes that initiate biofilm formation on tooth surfaces. An isolated S. gordonii::Tn917-lac biofilm-defective mutant contained a transposon insertion in an open reading frame (ORF) encoding a homolog of NosX of Ralstonia eutropha, a putative maturation factor of nitrous oxide reductase. Located downstream are two genes, qor1 and qor2, predicted to encode two putative NADPH quinone oxidoreductases. These three genes are cotranscribed, forming a putative oxidative stress response (osr) operon in S. gordonii. Inactivation of nosX, qor1, or qor2 resulted in biofilm-defective phenotypes. Expression of nosX, measured by the β-galactosidase activity of the nosX::Tn917-lac mutant, was growth-phase dependent and enhanced when grown under aerobic conditions or in the presence of paraquat. Real-time reverse transcription-PCR revealed that nosX-specific mRNA levels were increased approximately 8.4 and 3.5 fold in biofilm-derived cells grown on plastic and glass, respectively, when compared to planktonic cells. Expression of nosX increased 19.9 fold in cells grown under aerated aerobic conditions and 4.7 fold in cells grown under static aerobic conditions. Two ORFs immediately adjacent to the osr operon encode a putative NADH oxidase (Nox) and a putative thiol-specific antioxidant enzyme (AhpC, for alkyl hydroperoxide peroxidase C). Expression of nox and ahpC was also significantly increased in cells grown under aerated and static aerobic conditions when compared to anaerobic conditions. In addition, nox expression was increased in biofilm cells compared to planktonic cells. These genes may be part of an island that deals with oxidoreductive response, some of which may be important in S. gordonii biofilm formation.
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Hoque, M. A., V. Aravinthan, and N. M. Pradhan. "Assessment on activated sludge models for acetate biodegradation under aerobic conditions." Water Science and Technology 60, no. 4 (April 1, 2009): 983–94. http://dx.doi.org/10.2166/wst.2009.446.
Повний текст джерелаАнотація:
A comparison of four different established models along with parameter estimation was carried out in order to explain the aerobic biodegradation of acetate in an activated sludge system. These models were investigated using experimental OUR data from batch experiments of three different concentration studies. Model calibration reveals that ASM1 model is not suitable to explain the observed experimental OUR during the famine phase implying storage compounds could play an important role during that stage. Besides, the model corresponds to the accumulation concept and is not well fitted for all concentrations studies though it includes the storage phenomena. Both the ASM3 model and the model for simultaneous storage and growth on substrate can well describe the acetate biodegradation process, however the OUR data alone is not sufficient to justify the suitability of those models. Simulated profiles using the model outputs demonstrate that storage is overestimated while ammonia degradation is underestimated in ASM3 compared to simultaneous growth and storage model. The current study also gives reasonable outcomes related to parameter estimation as compared with previous study which is statistically interpreted in this paper.
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Kirkwood, K. M., S. Ebert, J. M. Foght, P. M. Fedorak, and M. R. Gray. "Bacterial biodegradation of aliphatic sulfides under aerobic carbon- or sulfur-limited growth conditions." Journal of Applied Microbiology 99, no. 6 (December 2005): 1444–54. http://dx.doi.org/10.1111/j.1365-2672.2005.02723.x.
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Surmann, Kristin, Marius Stopp, Sebastian Wörner, Vishnu M. Dhople, Uwe Völker, Gottfried Unden, and Elke Hammer. "Fumarate dependent protein composition under aerobic and anaerobic growth conditions in Escherichia coli." Journal of Proteomics 212 (February 2020): 103583. http://dx.doi.org/10.1016/j.jprot.2019.103583.
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Ni, Bing-Jie, and Han-Qing Yu. "Simulation of heterotrophic storage and growth processes in activated sludge under aerobic conditions." Chemical Engineering Journal 140, no. 1-3 (July 2008): 101–9. http://dx.doi.org/10.1016/j.cej.2007.09.017.
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Kato, Yoichiro, Ryosuke Tajima, Koki Homma, Akiko Toriumi, Junko Yamagishi, Tatsuhiko Shiraiwa, Poonsak Mekwatanakarn, and Boonrat Jongdee. "Root growth response of rainfed lowland rice to aerobic conditions in northeastern Thailand." Plant and Soil 368, no. 1-2 (November 28, 2012): 557–67. http://dx.doi.org/10.1007/s11104-012-1538-3.
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Wett, B., M. Hell, G. Nyhuis, T. Puempel, I. Takacs, and S. Murthy. "Syntrophy of aerobic and anaerobic ammonia oxidisers." Water Science and Technology 61, no. 8 (April 1, 2010): 1915–22. http://dx.doi.org/10.2166/wst.2010.969.
Повний текст джерелаАнотація:
Deammonification is known as an efficient and resource saving sidestream process option to remove the nitrogen load from sludge liquors. The transfer of the intermediate product nitrite between both syntrophic groups of organisms – aerobic and anaerobic ammonia oxidizers (AOB) – appears very sensitive to process conditions such as temperature, dissolved oxygen (DO) and operating nitrite level. Growth kinetics for aerobic and anaerobic AOBs differ by one order of magnitude and require an adequate selection of sludge retention time. This paper provides measurement- and model-based results on how selected sludge wasting impacts population dynamics in a suspended growth deammonification system. Anammox enrichment up to a doubled portion in mixed liquor solids can substantially improve process stability in difficult conditions. A case-study on low temperature operations outlines two possible strategies to balance syntrophic consumption of ammonium and nitrite.
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Martin, Angela C., Usha Nair, Judith P. Armitage, and Janine R. Maddock. "Polar Localization of CheA2 in Rhodobacter sphaeroides Requires Specific Che Homologs." Journal of Bacteriology 185, no. 16 (August 15, 2003): 4667–71. http://dx.doi.org/10.1128/jb.185.16.4667-4671.2003.
Повний текст джерелаАнотація:
ABSTRACT Rhodobacter sphaeroides is a motile bacterium that has multiple chemotaxis genes organized predominantly in three major operons (cheOp1, cheOp2, and cheOp3). The chemoreceptor proteins are clustered at two distinct locations, the cell poles and in one or more cytoplasmic clusters. One intriguing possibility is that the physically distinct chemoreceptor clusters are each composed of a defined subset of specific chemotaxis proteins, including the chemoreceptors themselves plus specific CheW and CheA proteins. Here we report the subcellular localization of one such protein, CheA2, under aerobic and photoheterotrophic growth conditions. CheA2 is predominantly clustered and localized at the cell poles under both growth conditions. Furthermore, its localization is dependent upon one or more genes in cheOp2 but not those of cheOp1 or cheOp3. In E. coli, the polar localization of CheA depends upon CheW. The R. sphaeroides cheOp2 contains two cheW genes. Interestingly, CheW2 is required under both aerobic and photoheterotrophic conditions, whereas CheW3 is not required under aerobic conditions but appears to play a modest role under photoheterotrophic conditions. This suggests that R. sphaeroides contains at least two distinct chemotaxis complexes, possibly composed of proteins dedicated for each subcellular location. Furthermore, the composition of these spatially distinct complexes may change under different growth conditions.
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Weber, Arnim, Stephanie A. Kögl, and Kirsten Jung. "Time-Dependent Proteome Alterations under Osmotic Stress during Aerobic and Anaerobic Growth in Escherichia coli." Journal of Bacteriology 188, no. 20 (October 1, 2006): 7165–75. http://dx.doi.org/10.1128/jb.00508-06.
Повний текст джерелаАнотація:
ABSTRACT Escherichia coli lives in the mammalian gastrointestinal tract anaerobically at high osmolarity as well as in the soil aerobically at varying osmolarities. Adaptation to these varying environmental conditions is crucial for growth and survival of E. coli. Two-dimensional protein gels were used to visualize global time-dependent changes (10 to 60 min) in the proteome of cells responding to osmotic stress (0.4 M NaCl or 0.7 M sorbitol) under aerobic or anaerobic conditions. The protein profiles revealed an induction of 12 proteins (Dps, HchA, HdhA, InfB, OsmC, OsmY, ProX, KatE, PspA, TalA, TktB, and TreF) under osmotic stress in an aerobic milieu. Eleven additional proteins (OtsB, YceI, YciE, YciF, YgaU, YjbJ, AcnA, MetL, PoxB, Ssb, and YhbO) were induced by osmotic stress imposed by NaCl. Most of the accumulated proteins were cross-protecting proteins (e.g., OsmY, OsmC, Dps, and KatE) which are regulated at the transcriptional level predominantly by RpoS and other regulators (e.g., integration host factor, OxyR, H-NS, LRP, and FIS). Comparative analysis of the proteome of E. coli grown under aerobic or anaerobic conditions under osmotic stress (NaCl) revealed an overlap of the up-regulated proteins of more than 50%. Ten proteins (PoxB, AcnA, TalA, TktB, KatE, PspA, Ssb, TreF, MetL, and YhbO) were detectable only under aerobic, high-osmolality conditions. Time-dependent alterations of the proteome were monitored, allowing classification of the up-regulated proteins into early, middle, and long-term phases of adaptation. Only a few proteins were found to be down-regulated upon osmotic stress.
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Nishimura, Taku, Haruhiko Teramoto, Alain A. Vertès, Masayuki Inui, and Hideaki Yukawa. "ArnR, a Novel Transcriptional Regulator, Represses Expression of the narKGHJI Operon in Corynebacterium glutamicum." Journal of Bacteriology 190, no. 9 (February 22, 2008): 3264–73. http://dx.doi.org/10.1128/jb.01801-07.
Повний текст джерелаАнотація:
ABSTRACT The narKGHJI operon that comprises putative nitrate/nitrite transporter (narK) and nitrate reductase (narGHJI) genes is required for the anaerobic growth of Corynebacterium glutamicum with nitrate as a terminal electron acceptor. In this study, we identified a gene, arnR, which encodes a transcriptional regulator that represses the expression of the narKGHJI operon in C. glutamicum cells under aerobic conditions. Disruption of arnR induced nitrate reductase activities of C. glutamicum cells and increased narKGHJI mRNA levels under aerobic growth conditions. DNA microarray analyses revealed that besides the narKGHJI operon, the hmp gene, which encodes flavohemoglobin, is negatively regulated by ArnR under aerobic conditions. Promoter-reporter assays indicated that arnR gene expression was positively autoregulated by its gene product, ArnR, under both aerobic and anaerobic conditions. Electrophoretic mobility shift assay experiments showed that purified hexahistidyl-tagged ArnR protein specifically binds to promoter regions of the narKGHJI operon and the hmp and arnR genes. A consensus sequence, TA(A/T)TTAA(A/T)TA, found in the promoter regions of these genes was demonstrated to be involved in the binding of ArnR. Effects on LacZ activity by deletion of the ArnR binding sites within the promoter regions fused to the reporter gene were consistent with the view that the expression of the narKGHJI operon is repressed by the ArnR protein under aerobic conditions, whereas the expression of the arnR gene is autoinduced by ArnR.
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Abbott, Derek A., Erwin Suir, Giang-Huong Duong, Erik de Hulster, Jack T. Pronk, and Antonius J. A. van Maris. "Catalase Overexpression Reduces Lactic Acid-Induced Oxidative Stress in Saccharomyces cerevisiae." Applied and Environmental Microbiology 75, no. 8 (February 27, 2009): 2320–25. http://dx.doi.org/10.1128/aem.00009-09.
Повний текст джерелаАнотація:
ABSTRACT Industrial production of lactic acid with the current pyruvate decarboxylase-negative Saccharomyces cerevisiae strains requires aeration to allow for respiratory generation of ATP to facilitate growth and, even under nongrowing conditions, cellular maintenance. In the current study, we observed an inhibition of aerobic growth in the presence of lactic acid. Unexpectedly, the cyb2Δ reference strain, used to avoid aerobic consumption of lactic acid, had a specific growth rate of 0.25 h−1 in anaerobic batch cultures containing lactic acid but only 0.16 h−1 in identical aerobic cultures. Measurements of aerobic cultures of S. cerevisiae showed that the addition of lactic acid to the growth medium resulted in elevated levels of reactive oxygen species (ROS). To reduce the accumulation of lactic acid-induced ROS, cytosolic catalase (CTT1) was overexpressed by replacing the native promoter with the strong constitutive TPI1 promoter. Increased activity of catalase was confirmed and later correlated with decreased levels of ROS and increased specific growth rates in the presence of high lactic acid concentrations. The increased fitness of this genetically modified strain demonstrates the successful attenuation of additional stress that is derived from aerobic metabolism and may provide the basis for enhanced (micro)aerobic production of organic acids in S. cerevisiae.