scholarly journals Phototrophic lactate utilization by Rhodopseudomonas palustris is stimulated by co-utilization with additional substrates

2018 ◽  
Author(s):  
Alekhya Govindaraju ◽  
James B McKinlay ◽  
Breah LaSarre
Keyword(s):  
Organic Acids ◽  
Rhodopseudomonas Palustris ◽  
Substrate Utilization ◽  
Carbon Utilization ◽  
Mixed Substrate ◽  
Metabolic Versatility ◽  
Carbon Substrates ◽  
Glycerol Utilization ◽  
Lactate Utilization ◽  
Time Frames

The phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris is known for its metabolic versatility and is of interest for various industrial and environmental applications. Despite decades of research on R. palustris growth under diverse conditions, patterns of R. palustris growth and carbon utilization with mixtures of carbon substrates remain largely unknown. R. palustris readily utilizes most short chain organic acids but cannot readily use lactate as a sole carbon source. Here we investigated the influence of mixed-substrate utilization on phototrophic lactate consumption by R. palustris. We found that lactate was simultaneously utilized with a variety of other organic acids and glycerol in time frames that were insufficient for R. palustris growth on lactate alone. Thus, lactate utilization by R. palustris was expedited by its co-utilization with additional substrates. Separately, experiments using carbon pairs that did not contain lactate revealed acetate-mediated inhibition of glycerol utilization in R. palustris. This inhibition was specific to the acetate-glycerol pair, as R. palustris simultaneously utilized acetate or glycerol when either was paired with succinate or lactate. Overall, our results demonstrate that (i) R. palustris commonly employs simultaneous mixed-substrate utilization, (ii) mixed-substrate utilization expands the spectrum of readily utilized organic acids in this species, and (iii) R. palustris has the capacity to exert carbon catabolite control in a substrate-specific manner.

scholarly journals Phototrophic Lactate Utilization byRhodopseudomonas palustrisIs Stimulated by Coutilization with Additional Substrates

2019 ◽  
Vol 85 (11) ◽  
Author(s):  
Alekhya Govindaraju ◽  
James B. McKinlay ◽  
Breah LaSarre
Keyword(s):  
Carbon Source ◽  
Organic Acids ◽  
Rhodopseudomonas Palustris ◽  
Practical Importance ◽  
Substrate Utilization ◽  
Mixed Substrate ◽  
Content Type ◽  
Bacterial Physiology ◽  
Carbon Substrates ◽  
Lactate Utilization

ABSTRACTThe phototrophic purple nonsulfur bacteriumRhodopseudomonas palustrisis known for its metabolic versatility and is of interest for various industrial and environmental applications. Despite decades of research onR. palustrisgrowth under diverse conditions, patterns ofR. palustrisgrowth and carbon utilization with mixtures of carbon substrates remain largely unknown.R. palustrisreadily utilizes most short-chain organic acids but cannot readily use lactate as a sole carbon source. Here we investigated the influence of mixed-substrate utilization on phototrophic lactate consumption byR. palustris. We found that lactate was simultaneously utilized with a variety of other organic acids and glycerol in time frames that were insufficient forR. palustrisgrowth on lactate alone. Thus, lactate utilization byR. palustriswas expedited by its coutilization with additional substrates. Separately, experiments using carbon pairs that did not contain lactate revealed acetate-mediated inhibition of glycerol utilization inR. palustris. This inhibition was specific to the acetate-glycerol pair, asR. palustrissimultaneously utilized acetate or glycerol when either was paired with succinate or lactate. Overall, our results demonstrate that (i)R. palustriscommonly employs simultaneous mixed-substrate utilization, (ii) mixed-substrate utilization expands the spectrum of readily utilized organic acids in this species, and (iii)R. palustrishas the capacity to exert carbon catabolite control in a substrate-specific manner.IMPORTANCEBacterial carbon source utilization is frequently assessed using cultures provided single carbon sources. However, the utilization of carbon mixtures by bacteria (i.e., mixed-substrate utilization) is of both fundamental and practical importance; it is central to bacterial physiology and ecology, and it influences the utility of bacteria as biotechnology. Here we investigated mixed-substrate utilization by the model organismRhodopseudomonas palustris. Using mixtures of organic acids and glycerol, we show thatR. palustrisexhibits an expanded range of usable carbon substrates when provided substrates in mixtures. Specifically, coutilization enabled the prompt consumption of lactate, a substrate that is otherwise not readily used byR. palustris. Additionally, we found thatR. palustrisutilizes acetate and glycerol sequentially, revealing that this species has the capacity to use some substrates in a preferential order. These results provide insights intoR. palustrisphysiology that will aid the use ofR. palustrisfor industrial and commercial applications.

scholarly journals Towards sustainable bioplastic production in resource limited environments using the photoferroautotrophic and photoelectroautotrophic bacteriumRhodopseudomonas palustrisTIE-1

2017 ◽  
Author(s):  
Tahina Onina Ranaivoarisoa ◽  
Karthikeyan Rengasamy ◽  
Michael S. Guzman ◽  
Rajesh Singh ◽  
Arpita Bose
Keyword(s):  
Energy Source ◽  
Carbon Source ◽  
Organic Carbon ◽  
Ferrous Iron ◽  
Rhodopseudomonas Palustris ◽  
Electron Source ◽  
Light Energy ◽  
Attractive Alternative ◽  
Metabolic Versatility ◽  
Phb Production

ABSTRACTBioplastics are an attractive alternative to petroleum-derived plastics because of the harmful environmental effects of conventional plastics and the impending fossil fuel crisis. Polyhydroxybutyrate (PHB) is a well-known bioplastic that is produced by several microbes using organic carbon sources. Autotrophic (using carbon dioxide or CO2) PHB production is reported for only a few organisms. Sustainable PHB bioproduction using other autotrophic microbes needs to be explored.Rhodopseudomonas palustris, a metabolically versatile purple non-sulfur bacterium (PNSB) is known to produce PHBs under photoheterotrophic conditions.Rhodopseudomonas palustrisstrain TIE-1 demonstrates extended metabolic versatility by using electron sources such as ferrous iron and poised electrodes for photoautotrophy. Here we report the ability of TIE-1 to produce PHB under photoferroautotrophic (light - energy source, ferrous iron - electron source and CO2- carbon source) and photoelectroautotrophic (light - energy source, poised electrodes - electron source and CO2- carbon source) growth conditions. PHB accumulation was observed both under nitrogen (N2) fixing and non-N2fixing conditions. For comparison, we determined PHB production under chemoheterotrophic, photoheterotrophic and photoautotrophic conditions using hydrogen as the electron donor. Photoferroautotrophic and photoelectroautotrophic PHB production was on par with that observed from organic carbon substrates such as butyrate. PHB production increased during N2fixation under photoheterotrophic conditions but not during photoautotrophic growth. Electron microscopy confirmed that TIE-1 cells accumulate PHBs internally under the conditions that showed highest production. However, gene expression analysis suggests that PHB cycle genes are not differentially regulated despite observable changes in biopolymer production.

Biochemical limits to microbial growth yields: An analysis of mixed substrate utilization

1988 ◽  
Vol 32 (1) ◽  
pp. 86-94 ◽  
Author(s):  
P. J. F. Gommers ◽  
B. J. van Schie ◽  
J. P. van Dijken ◽  
J. G. Kuenen
Keyword(s):  
Microbial Growth ◽  
Substrate Utilization ◽  
Growth Yields ◽  
Mixed Substrate

Beneficial effect of Rhodopseudomonas palustris on in vitro rumen digestion and fermentation

2020 ◽  
Vol 11 (1) ◽  
pp. 91-99
Author(s):  
Y.Y. Chen ◽  
Y.L. Wang ◽  
W.K. Wang ◽  
Z.W. Zhang ◽  
X.M. Si ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Rhodopseudomonas Palustris ◽  
Gas Production ◽  
High Yield ◽  
Microbial Fermentation ◽  
Ruminal Fermentation ◽  
Dose Rates ◽  
Lactating Cows ◽  
Metabolic Versatility

As a member of photosynthetic bacteria, Rhodopseudomonas palustris, which has extraordinary metabolic versatility, has been applied as one of potential probiotics in feed industry. To explore whether R. palustris can increase rumen microbial viability and thus improve microbial fermentation, a 2×5 factorial experiment was conducted to evaluate the effect of R. palustris at dose rates of 0, 1.3, 2.6, 3.9, 5.2×106 cfu/ml on ruminal fermentation of two representative total mixed rations (HY, a ration for high-yield (>32 kg/d) lactating cows; LY, a ration for low-yield (<25 kg/d) lactating cows). After a 48 h in vitro rumen incubation, both rations resulted in different fermentation characteristics. The HY in comparison with LY group presented greater in vitro dry matter disappearance (IVDMD), cumulative gas production (GP48) and total volatile fatty acids (VFA, P<0.01). Increasing R. palustris addition linearly increased IVDMD (P<0.01) and GP48 (P<0.05), and the IVDMD increment in response to R. palustris addition was greater in LY than HY group (6.4% vs 1.4%). Meanwhile, increasing R. palustris addition also linearly enhanced microbial protein synthesis and increased total VFA production (P<0.01), especially in LY group (up to 21.5% and 24.5% respectively). Unchanged acetate and declined propionate in molar percentage were observed in response to the R. palustris addition. Furthermore, increasing R. palustris addition altered fermentation gas composition in which molar O2 proportion in headspace of fermentation system was linearly reduced by 46.1% in LY and 32.9% in HY group, respectively (P<0.01), and methane production in both ration groups was enhanced by 1.9-4.1% (P=0.02). In summary, the R. palustris addition exhibited high potential for promoting the growth of rumen microorganism and enhancing microbial fermentation towards non-glucogenic energy supply by maintaining an anaerobic environment to microbe equilibrium.

Effects of coronary hypotension on myocardial substrate utilization

1975 ◽  
Vol 228 (2) ◽  
pp. 365-368 ◽  
Author(s):  
JJ Spitzer ◽  
AA Bechtel ◽  
LT Archer ◽  
MR Black ◽  
LJ Greenfield ◽  
...  
Keyword(s):  
Diastolic Pressure ◽  
Isolated Heart ◽  
Endotoxic Shock ◽  
Control Period ◽  
Substrate Utilization ◽  
Relative Preference ◽  
Severe Hypotension ◽  
Myocardial Substrate ◽  
Lactate Uptake ◽  
Lactate Utilization

Changes in myocardial substrate utilization were studied after experimental coronary hypotension in the isolated dog heart perfused with the blood of a large donor animal. After a control period (100 mmHg) the afterload of the isolated heart was adjusted to 50 mmHg and kept at that level for 4 h. After this period, a second control observation was made at a 100-mmHg afterload. Coronary sinus blood flow and oxygen consumption decreased during hypotension and returned to normal during the second control period. Myocardial free fatty acid (FFA) uptake and oxidation did not change significantly. Lactate uptake and the percentage of CO2 derived from myocardial lactate utilization were both diminished during hypotension. These changes were not present during the second control period. Glucose uptake and myocardial respiratory quotient were decreased during the hypotensive period. Half the hearts exhibited elevated end-diastolic pressure after hypotension, but no metabolic differences were detectable between the failing and nonfailing hearts. Thus, prolonged severe hypotension caused a relative preference of FFA oxidation and diminished lactate and glucose uptakes by the myocardium. These changes were quite different from those obtained during experimental hemorrhagic or endotoxic shock.

Glucose utilization dependence on preferred carbon-source growth in an Arthrobacter sp.

1973 ◽  
Vol 19 (4) ◽  
pp. 541-543 ◽  
Author(s):  
R. A. Sokol ◽  
D. A. Klein
Keyword(s):  
Carbon Source ◽  
Glucose Utilization ◽  
Substrate Utilization ◽  
Mixed Substrate

Arthrobacter sp., ATCC 25581, is incapable of glucose utilization except diauxically following growth on a preferred carbon source such as succinate. This phenomenon appears to be a novel mixed substrate utilization relationship.

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