scholarly journals The effect of structure and a secondary carbon source on the microbial degradation of chlorophenoxy acids

Chemosphere ◽  
2010 ◽  
Vol 79 (11) ◽  
pp. 1084-1088 ◽  
Author(s):  
S. Evangelista ◽  
D.G. Cooper ◽  
V. Yargeau
Keyword(s):  
Carbon Source ◽  
Microbial Degradation ◽  
Chlorophenoxy Acids ◽  
Effect Of Structure ◽  
Secondary Carbon

scholarly journals Lipid accumulation capability of typical non‐acclimated activated sludge microbial consortia using methane gas as secondary carbon source

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Dhan Lord B. Fortela ◽  
Wayne Sharp ◽  
Emmanuel Revellame ◽  
Andrei Chistoserdov ◽  
William Holmes ◽  
...  
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Lipid Accumulation ◽  
Microbial Consortia ◽  
Methane Gas ◽  
Acclimated Activated Sludge ◽  
Secondary Carbon

The Effects of the Secondary Carbon Source on the Biodegradation of Chlorinated Phenols in Biofilm Reactors

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2113-2116 ◽  
Author(s):  
C. J. Lu ◽  
S. J. Chen
Keyword(s):  
Carbon Source ◽  
Batch Reactors ◽  
Chlorinated Phenols ◽  
Biofilm Reactors ◽  
Secondary Carbon

The effects of the presence of a secondary carbon source on the biodegradation of chlorinated phenols were studied with column biofilm reactors. The biodegradability of chlorinated phenols was studied with a series of batch reactors. The biodegradability of chlorinated phenols was to follow the order of phenol > 2,4-dichlorophenol > 4-chIorophenol > 2,4,6-trichlorophenol > 2-chlorophenol > 3-chloro-phenol. The presence of a relatively more biodegradable but higher chlorinated phenol, such as 2,4,6-trichlorophenol, enhanced the biodégradation of a less chlorinated butrecalcitrantphenol, such as 2-chlorophenol. The addition of phenol, an easily biodegradable compound, generally decreased the biodegradation of chlorinated phenols.

scholarly journals Production of Polyhydroxyalkanoates (PHAs) by Vibrio alginolyticus Strains Isolated from Salt Fields

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6283
Author(s):  
Hong-Fei Li ◽  
Meng-Ru Wang ◽  
Lin-Yue Tian ◽  
Zheng-Jun Li
Keyword(s):  
Carbon Source ◽  
Organic Acids ◽  
Water Samples ◽  
Opportunistic Pathogen ◽  
Vibrio Alginolyticus ◽  
Culture Temperature ◽  
Waste Glycerol ◽  
Nacl Concentration ◽  
Pha Production ◽  
Secondary Carbon

Vibrio alginolyticus is a halophilic organism usually found in marine environments. It has attracted attention as an opportunistic pathogen of aquatic animals and humans, but there are very few reports on polyhydroxyalkanoate (PHA) production using V. alginolyticus as the host. In this study, two V. alginolyticus strains, LHF01 and LHF02, isolated from water samples collected from salt fields were found to produce poly(3-hydroxybutyrate) (PHB) from a variety of sugars and organic acids. Glycerol was the best carbon source and yielded the highest PHB titer in both strains. Further optimization of the NaCl concentration and culture temperature improved the PHB titer from 1.87 to 5.08 g/L in V. alginolyticus LHF01. In addition, the use of propionate as a secondary carbon source resulted in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). V. alginolyticus LHF01 may be a promising host for PHA production using cheap waste glycerol from biodiesel refining.

scholarly journals Staphylococcus aureus does not synthesize arginine from proline under physiological conditions

2022 ◽  
Author(s):  
Taeok Bae ◽  
Bohyun Jeong ◽  
Majid Ali Shah ◽  
Eunjung Roh ◽  
Kyeong Kyu Kim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Carbon Source ◽  
Catabolite Repression ◽  
Deletion Mutant ◽  
Animal Experiment ◽  
Carbon Catabolite Repression ◽  
Ectopic Expression ◽  
Proline Dehydrogenase ◽  
Physiological Conditions ◽  
Secondary Carbon

The Gram-positive pathogen Staphylococcus aureus is the only bacterium known to synthesize arginine from proline via the arginine-proline interconversion pathway, despite having genes for the well-conserved glutamate pathway. Since the proline-arginine interconversion pathway is repressed by CcpA-mediated carbon catabolite repression (CCR), CCR has been attributed to the arginine auxotrophy of S. aureus. Using ribose as a secondary carbon source, here, we demonstrate that S. aureus arginine auxotrophy is not due to CCR but due to the inadequate concentration of proline degradation product. Proline is degraded by proline dehydrogenase (PutA) into pyrroline-5-carboxylate (P5C). Although the PutA expression was fully induced by ribose, the P5C concentration remained insufficient to support arginine synthesis because P5C was constantly consumed by the P5C reductase ProC. When the P5C concentration was artificially increased by either PutA overexpression or proC-deletion, S. aureus could synthesize arginine from proline regardless of carbon source. In contrast, when the P5C concentration was reduced by overexpression of proC, it inhibited the growth of the ccpA-deletion mutant without arginine. Intriguingly, the ectopic expression of the glutamate pathway enzymes converted S. aureus into arginine prototroph. In an animal experiment, the arginine-proline interconversion pathway was not required for the survival of S. aureus. Based on these results, we concluded that S. aureus does not synthesize arginine from proline under physiological conditions. We also propose that arginine auxotrophy of S. aureus is not due to the CcpA-mediated CCR but due to the inactivity of the conserved glutamate pathway.

scholarly journals PAOX1 expression in mixed-substrate continuous cultures of Komagataella phaffii (Pichia pastoris) is completely determined by methanol uptake regardless of the secondary carbon source: a simplifying principle for predicting recombinant protein production.

2021 ◽  
Author(s):  
Anamika Singh ◽  
Atul Narang
Keyword(s):  
Carbon Source ◽  
Oxygen Demand ◽  
Continuous Cultures ◽  
Mixed Substrate ◽  
Komagataella Phaffii ◽  
Uptake Rates ◽  
Wide Range ◽  
Hyperbolic Curve ◽  
Expression Rate ◽  
Secondary Carbon

The expression of recombinant proteins by the AOX1 promoter of Komagataella phaffii is typically induced by adding methanol to the cultivation medium. Since growth on methanol imposes a high oxygen demand, the medium is often supplemented with an additional "secondary" carbon source which serves to reduce the consumption of methanol, and hence, oxygen. Early research recommended the use of glycerol as the secondary carbon source, but more recent studies recommend the use of sorbitol because glycerol represses PAOX1 expression. To assess the validity of this recommendation, we measured the steady state concentrations of biomass, residual methanol, and AOX1 over a wide range of dilution rates (0.02-0.20 h-1) in continuous cultures of the Mut+ strain fed with methanol, methanol + glycerol, and methanol + sorbitol. We find that when the specific AOX1 expression and methanol uptake rates for each of the three feeds are plotted against each other, they collapse into a single hyperbolic curve. The specific AOX1 expression rate is therefore completely determined by the specific methanol uptake rate regardless of the existence (present/absent) and type (repressing/non-repressing) of the secondary carbon source. In particular, cultures fed with methanol + glycerol and methanol + sorbitol that consume methanol at equal rates also express the protein at equal rates and levels. Now, it turns out that the simple unstructured model developed by Egli and co-workers can predict the specific methanol uptake rates of single- and mixed-substrate cultures over a wide range of dilution rates and feed concentrations. By combining this model with our data, we derive simple formulas that predicts the protein expression rates and levels of single- and mixed-substrate cultures over a wide range of conditions.

scholarly journals Disruption of GABA shunt affects Trichoderma atroviride response to nutritional and environmental stimuli

2016 ◽  
Vol 9 (2) ◽  
pp. 109-113
Author(s):  
Ľuboš Nižnanský ◽  
Ľudovít Varečka ◽  
Svetlana Kryštofová
Keyword(s):  
Carbon Source ◽  
Glutamate Decarboxylase ◽  
Room Temperature ◽  
Inhibitory Effect ◽  
Cellulase Production ◽  
Extension Rate ◽  
Trichoderma Atroviride ◽  
Optimal Temperature ◽  
Higher Temperature ◽  
Secondary Carbon

Abstract The fungus Trichoderma atroviride is a member of the genus Trichoderma to which belong many species known for high cellulase production, formation of various antibiotics, plant biocontrol and antagonistic activities against other fungi. Deletion of T. atroviride glutamate decarboxylase gene gad caused minor defects in germination, hyphal branching, slower growth and disruption of conidiation pattern. GABA can be used by fungi as a secondary carbon source and as a primary nitrogen source. We analyzed the effect of different nutrient compositions and environmental conditions (light and temperature) on growth and development of T. atroviride in strains defective in the functional GAD. The gad mutants grown on NH4NO3 as a sole carbon source grew slower and formed conidiation bands closer to each other which was clearly demonstrated during their cultivation in race tubes. The gad mutants exhibited slightly lower apical extension growth rate at the room temperature but their apical extension rate dropped significantly at 30 °C. Higher temperature had also inhibitory effect on gad mutant conidiation, whereas 30 °C seems optimal temperature for the parental strain. The optimal temperature for gad mutant conidiation was lower than in F534, about 25 °C.

Study of the reductive dechlorination of pentachlorophenol by a methanogenic consortium

1995 ◽  
Vol 41 (10) ◽  
pp. 862-868 ◽  
Author(s):  
P. Juteau ◽  
R. Beaudet ◽  
G. McSween ◽  
F. Lépine ◽  
J.-G. Bisaillon
Keyword(s):  
Heat Treatment ◽  
Carbon Source ◽  
Yeast Extract ◽  
Reductive Dechlorination ◽  
Para Position ◽  
Vigorous Agitation ◽  
Good Substrate ◽  
Spore Forming Bacteria ◽  
Methanogenic Consortium ◽  
Secondary Carbon

Pentachlorophenol (PCP) dechlorination by a methanogenic consortium was observed when glucose, formate, lactate, or yeast extract was present in the mineral medium as a secondary carbon source. Acetate was not a good substrate to sustain dechlorination. The consortium was able to dechlorinate the different monochlorophenols, although the chlorine in position ortho and meta was removed more readily than in para position. Dechlorination was most efficient at 37 °C. At 45 °C, the first PCP dechlorination steps were very rapid, but 3,5-dichlorophenol (3,5-DCP) was not further dechlorinated. At 15 and 4 °C, dechlorination was very slow. The dechlorination of PCP to 3-chlorophenol (3-CP) was still observed after the consortium had been subjected to heat treatment (80 °C, 60 min), suggesting that spore-forming bacteria were responsible. The dechlorinating activity of the consortium was significantly reduced by the presence of hydrogen, 2-bromoethanosulfonic acid (BESA), or sulfate but not of nitrate. The dechlorination of 3-CP was completely inhibited by heat treatment or the presence of BESA, suggesting that a syntrophic microorganism would be involved. Vigorous agitation of the consortium stopped the dechlorination, but the presence of DEAE-Sephacel acting as a support was very efficient in restoring the activity, suggesting that association between certain members of the consortium was important.Key words: pentachlorophenol, dechlorination, anaerobic, methanogenesis.

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