Pyruvate fermentation by <i>Clostridium acetobutylicum</i>

Janati‐Idrissi, Rachid; Junelles, Anne-Marie; Kanouni, A. El; Petitdemange, H.; Gay, Robert

doi:10.1139/o89-110

Cited by 10 publications

(3 citation statements)

References 13 publications

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“…However, relative abundances of propionate and butyrate were 100 to 1000 times higher in sample PF12. Both organic compounds are well known products of microbial fermentation reactions, with the former being an intermediate of pyruvate and lactate fermentation (Schultz and Weaver, 1982; Janati-Idrissi et al, 1989). The observed decrease in both PEGs and poly-carbon compound concentrations from PF12 to PF16 indicates a probable temporal shift in microbial community (Figure 4) from predominantly fermentative organic degradation pathways of drilling fluid-derived residual PEG compounds to an increasing potential for respiratory degradation of the biodegradation products of fermentative reactions, all occurring within the pre-scCO 2 injection phase.…”

Section: Discussionmentioning

confidence: 99%

Changes in the deep subsurface microbial biosphere resulting from a field-scale CO2 geosequestration experiment

Mu¹,

Boreham

Leong

et al. 2014

Front. Microbiol.

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Subsurface microorganisms may respond to increased CO2 levels in ways that significantly affect pore fluid chemistry. Changes in CO2 concentration or speciation may result from the injection of supercritical CO2 (scCO2) into deep aquifers. Therefore, understanding subsurface microbial responses to scCO2, or unnaturally high levels of dissolved CO2, will help to evaluate the use of geosequestration to reduce atmospheric CO2 emissions. This study characterized microbial community changes at the 16S rRNA gene level during a scCO2 geosequestration experiment in the 1.4 km-deep Paaratte Formation of the Otway Basin, Australia. One hundred and fifty tons of mixed scCO2 and groundwater was pumped into the sandstone Paaratte aquifer over 4 days. A novel U-tube sampling system was used to obtain groundwater samples under in situ pressure conditions for geochemical analyses and DNA extraction. Decreases in pH and temperature of 2.6 log units and 5.8°C, respectively, were observed. Polyethylene glycols (PEGs) were detected in the groundwater prior to scCO2 injection and were interpreted as residual from drilling fluid used during the emplacement of the CO2 injection well. Changes in microbial community structure prior to scCO2 injection revealed a general shift from Firmicutes to Proteobacteria concurrent with the disappearance of PEGs. However, the scCO2 injection event, including changes in response to the associated variables (e.g., pH, temperature and salinity), resulted in increases in the relative abundances of Comamonadaceae and Sphingomonadaceae suggesting the potential for enhanced scCO2 tolerance of these groups. This study demonstrates a successful new in situ sampling approach for detecting microbial community changes associated with an scCO2 geosequestration event.

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Section: Discussionmentioning

confidence: 99%

Changes in the deep subsurface microbial biosphere resulting from a field-scale CO2 geosequestration experiment

Mu¹,

Boreham

Leong

et al. 2014

Front. Microbiol.

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“…Although already low on glucose-glycerol cultures (compared with acetoneproducing cultures [21]), addition of pyruvate further decreased the level of acetoacetate decarboxylase by a factor of 10. Janati-Idrissi et al (8) reported a low acetoacetate decarboxylase biosynthesis during batch cultures on pyruvate as a carbon source at pH 4.8. Higher butyric acid production in the glucose-glycerolpyruvate culture compared with that grown on glucose-glycerol was associated with a higher level of expression of the PTB and BK. Under steady-state conditions, the in vitro PTB and BK activities (i.e., enzyme concentration) decreased linearly with the intracellular ATP concentration.…”

Section: Discussionmentioning

confidence: 99%

Regulation of Clostridium acetobutylicum metabolism as revealed by mixed-substrate steady-state continuous cultures: role of NADH/NAD ratio and ATP pool

1994

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Glycerol-glucose-fed (molar ratio of 2) chemostat cultures of Clostridium acetobutylicum were glucose limited but glycerol sufficient and had a high intracellular NADH/NAD ratio (I. Vasconcelos, L. Girbal, and P. Soucaille, J. Bacteriol. 176:1443-1450, 1994. We report here that the glyceraldehyde-3-phosphate dehydrogenase, one of the key enzymes of the glycolytic pathway, is inhibited by high NADH/NAD ratios. Partial substitution of glucose by pyruvate while maintaining glycerol concentration at a constant level allowed a higher consumption of glycerol in steady-state continuous cultures. However, glycerol-sufficient cultures had a constant flux through the glyceraldehyde-3-phosphate dehydrogenase and a constant NADH/NAD ratio. A high substitution of glucose by pyruvate [P/(G + P) value of 0.67 g/g] provided a carbon-limited culture with butanol and butyrate as the major end products. In this alcohologenic culture, the induction of the NADH-dependent butyraldehyde and the ferredoxin-NAD(P) reductases and the higher expression of alcohol dehydrogenases were related to a high NADH/NAD ratio and a low intracellular ATP concentration. In three different steady-state cultures, the in vitro phosphotransbutyrylase and butyrate-kinase activities decreased with the intracellular ATP concentration, suggesting a transcriptional regulation of these two genes, which are arranged in an operon (K. A. Walter, R V. Nair, R. V. Carry, G. N. Bennett, and E. T. Papoutsakis, Gene 134:107-111, 1993).Clostridium acetobutylicum, a strictly anaerobic spore-forming bacterium, usually shows a biphasic batch fermentation pattern. After producing acetate and butyrate during exponential growth, the organism switches to the formation of acetone, butanol, and ethanol shortly before entering the stationary phase. The mechanisms responsible for the onset of solventogenesis are currently the focus of much scientific research.In batch cultures, the initiation and sustained production of solvents are associated with a low extracellular and intracellular pH and a high undissociated butyric acid concentration (7,15,20). In continuous culture, ATP and NAD(P)H availabilities appear to play a key role in product selectivity. High ATP concentration related to low ATP demand or high efficiency of ATP generation would lead to enhanced solvent production (i) for glucose-sufficient cultures at a low pH with biomass recycling (12, 13); (ii) for iron-, nitrogen-, or phosphate-limited cultures (1, 2, 19); and (iii) during shifts induced on phosphatelimited cultures by lowering the pH or adding organic acids (6). Ethanol and butanol productions were associated with increased availability of reducing power (i) when the in vivo activity of the hydrogenase was decreased by CO gassing (5, 10, 13, 14) or by adding methyl viologen (6); (ii) during a shift in solvent production induced by lowering the pH when acetyl coenzyme A (CoA) was first converted to acetone (a pathway consuming no reducing energy), creating a redox imbalance (6); (iii) when an NADH pressure was ...

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“…Pyruvate uptake in the co-culture can be explained by the capability of C. acetobutylicum to metabolize pyruvate. It has been also reported that providing C. acetobutylicum with pyruvate as the sole carbon source results in the growth and production of mainly acetate and butyrate [ 38 ]. In another co-culture study, the removal of C. cellulolyticum metabolic products such as pyruvate and their associated inhibitory effects, by Rhodopseudomonas palustris in the co-culture of C. cellulolyticum and R. palustris has been reported as the underlying reason for the improved cellulose degradation and bacterial growth in this co-culture [ 39 ].…”

Section: Resultsmentioning

confidence: 99%

Characterizing metabolic interactions in a clostridial co-culture for consolidated bioprocessing

Salimi

Mahadevan

2013

BMC Biotechnol

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BackgroundClostridial co-culture containing cellulolytic and solventogenic species is a potential consolidated bioprocessing (CBP) approach for producing biochemicals and biofuels from cellulosic biomass. It has been demonstrated that the rate of cellulose utilization in the co-culture of Clostridium acetobutylicum and Clostridium cellulolyticum is improved compared to the mono-culture of C. cellulolyticum (BL 5:119-124, 1983). However, the metabolic interactions in this co-culture are not well understood. To investigate the metabolic interactions in this co-culture we dynamically characterized the physiology and microbial composition using qPCR.ResultsThe qPCR data suggested a higher growth rate of C. cellulolyticum in the co-culture compared to its mono-culture. Our results also showed that in contrast to the mono-culture of C. cellulolyticum, which did not show any cellulolytic activity under conditions similar to those of co-culture, the co-culture did show cellulolytic activity even superior to the C. cellulolyticum mono-culture at its optimal pH of 7.2. Moreover, experiments indicated that the co-culture cellulolytic activity depends on the concentration of C. acetobutylicum in the co-culture, as no cellulolytic activity was observed at low concentration of C. acetobutylicum, and thus confirming the essential role of C. acetobutylicum in improving C. cellulolyticum growth in the co-culture. Furthermore, butanol concentration of 350 mg/L was detected in the co-culture batch experiments.ConclusionThese results suggest the presence of synergism between these two species, while C. acetobutylicum metabolic activity significantly improves the cellulolytic activity in the co-culture, and allows C. cellulolyticum to survive under harsh co-culture conditions, which do not allow C. cellulolyticum to grow and metabolize cellulose independently. It is likely that C. acetobutylicum improves the cellulolytic activity of C. cellulolyticum in the co-culture through exchange of metabolites such as pyruvate, enabling it to grow and metabolize cellulose under harsh co-culture conditions.

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Pyruvate fermentation by Clostridium acetobutylicum

Cited by 10 publications

References 13 publications

Changes in the deep subsurface microbial biosphere resulting from a field-scale CO2 geosequestration experiment

Changes in the deep subsurface microbial biosphere resulting from a field-scale CO2 geosequestration experiment

Regulation of Clostridium acetobutylicum metabolism as revealed by mixed-substrate steady-state continuous cultures: role of NADH/NAD ratio and ATP pool

Characterizing metabolic interactions in a clostridial co-culture for consolidated bioprocessing

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