Level of enzymes involved in acetate, butyrate, acetone and butanol formation by Clostridium acetobutylicum

Andersch, Wolfram; Bahl, Hubert; Gottschalk, Gerhard

doi:10.1007/bf00504740

Cited by 243 publications

(150 citation statements)

References 17 publications

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“…Several biochemical studies have identified a hetero-dimeric CoA-transferase, CtfA/B, to play a key role in re-assimilation of acids and their conversion to the respective CoA-derivatives (Hartmanis et al 1984a;Wiesenborn et al 1989a) and it is, therefore, believed that this enzyme has a fundamentally different role in C. acetobutylicum compared to other bacteria (Wiesenborn et al 1989a). In addition, it facilitates the first step in the formation of acetone (Andersch et al 1983;. This view is supported by several experimental studies which had observed an increased transcription of the encoding genes, ctfA and ctfB, which are part of the sol operon (Grimmler et al 2011;Jones et al 2008), and an increased intracellular concentration of the protein during the pH-induced shift and during solventogenesis (Janssen et al 2010;Mao et al 2010).…”

Section: Introductionmentioning

confidence: 69%

“…pH-dependent specific enzymatic activities strongly regulate product formation (Andersch et al 1983;Dürre et al 1995;Jones and Woods 1986). Interestingly, experimental investigation of catalytic efficiencies has revealed that several enzymes operate optimally for either acidogenic or solventogenic intracellular pH levels and exhibit significant changes in their specific activities between both metabolic phases (Andersch et al 1983;Ho et al 2009).…”

Section: Adhe1 Acmentioning

confidence: 99%

“…Acidogenic-and solventogenic-specific kinetic parameters were introduced for those enzymes exhibiting significant changes of their specific activities. Experimental evidence notably indicates that the formation of acetate (Andersch et al 1983;, Eq. (4b), acetone (Ho et al 2009), Eq.…”

Section: Adhe1 Acmentioning

confidence: 99%

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Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum—evidence from a mathematical model

Millat

Voigt

Janssen

et al. 2014

Appl Microbiol Biotechnol

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(2014) Coenzyme A-transferaseindependent butyrate re-assimilation in Clostridium acetobutylicum -evidence from a mathematical model. Applied Microbiology and Biotechnology, 98 (21 A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum -Evidence from a mathematical model Abstract: The hetero-dimeric CoA-transferase CtfA/B is believed to be crucial for the metabolic transition from acidogenesis to solventogenesis in Clostridium acetobutylicum as part of the industrial-relevant acetone-butanol-ethanol (ABE) fermentation. Here, the enzyme is assumed to mediate re-assimilation of acetate and butyrate during a pH-induced metabolic shift and to faciliate the first step of acetone formation from acetoacetyl-CoA. However, recent investigations using phosphate-limited continuous cultures have questioned this common dogma.To adress the emerging experimental discrepancies, we investigated the mutant strain Cac-ctfA398s::CT using chemostat cultures. As a consequence of this mutation, the cells are unable to express functional ctfA and are thus lacking CoA-transferase activity. A mathematical model of the pH-induced metabolic shift, which was recently developed for the wild type, is used to analyse the observed behaviour of the mutant strain with a focus on re-assimilation activities for the two produced acids.Our theoretical analysis reveals that the ctfA mutant still re-assimilates butyrate, but not acetate. Based upon this finding, we conclude that C. acetobutylicum possesses a CoA-tranferase-independent butyrate uptake mechanism that is activated by decreasing pH levels. Furthermore, we observe that butanol formation is not inhibited under our experimental conditions, as suggested by previous batch culture experiments. In concordance with recent batch experiments, acetone formation is abolished in chemostat cultures using the ctfa mutant.

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Section: Introductionmentioning

confidence: 69%

Section: Adhe1 Acmentioning

confidence: 99%

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Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum—evidence from a mathematical model

Millat

Voigt

Janssen

et al. 2014

Appl Microbiol Biotechnol

Self Cite

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“…Activities of five enzymes involved in acid fermentation were examined. The measurement of acetate kinase（AK）activity and butyrate kinase（BK）activity were carried out as per (Allen et al, 1964); while phosphate transacetylase （PTA） and phosphate transbutyrylase （PTB） were carried out as per (Andersch et al, 1983); oxaloacetate transcarboxylase（OAATC） activity was carried out as per (Wood et al, 1969).…”

Section: Methodsmentioning

confidence: 99%

Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition

Zhang

et al. 2016

Journal of Environmental Sciences

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Waste activated sludge hydrolysis and acidification: a comparison between sodium hydroxide and steel slag addition AbstractAlkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH. 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment. AbstractAlkaline treatment with steel slag and NaOH addition were investigated at different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification.More solubilization of organic matters and much higher (volatile fatty acids) VFAs production at a shorter time can be achieved at pH 10 adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under same pH conditions. Phosphorus concentration in supernatant increased with fermentation time and pH in NaOH addition scenarios while in contrast most phosphorus were released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.

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“…One unit of enzyme activity is defined as the amount of enzyme that produces 1 mol of hydroxamic acid per min. Phosphotransacetylase and phosphotransbutyrylase were assayed with 0.2 mM acetyl-CoA and butyryl-CoA as the enzyme substrates, respectively, in 0.1 M potassium phosphate buffer (pH 7.4) following the method of Andersch et al (1983). The enzyme activity was monitored by following the liberation of coenzyme A at 405 nm, and one unit of enzyme is defined as the amount of enzyme converting 1 mol of acetyl-CoA or butyryl-CoA per min.…”

Section: Preparation Of Cell Extracts and Acid-forming Enzyme Assaysmentioning

confidence: 99%

Effect of pH on metabolic pathway shift in fermentation of xylose by Clostridium tyrobutyricum

Zhu

Yang

2004

Journal of Biotechnology

212

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The effect of pH (between 5.0 and 6.3) on butyric acid fermentation of xylose by Clostridium tyrobutyricum was studied. At pH 6.3, the fermentation gave a high butyrate production of 57.9 g l −1 with a yield of 0.38-0.59 g g −1 xylose and a reactor productivity up to 3.19 g l −1 h −1 . However, at low pHs (<5.7), the fermentation produced more acetate and lactate as the main products, with only a small amount of butyric acid. The metabolic shift from butyrate formation to lactate and acetate formation in the fermentation was found to be associated with changes in the activities of several key enzymes. The activities of phosphotransbutyrylase (PTB), which is the key enzyme controlling butyrate formation, and NAD-independent lactate dehydrogenase (iLDH), which catalyzes the conversion of lactate to pyruvate, were higher in cells producing mainly butyrate at pH 6.3. In contrast, cells at pH 5.0 had higher activities of phosphotransacetylase (PTA), which is the key enzyme controlling acetate formation, and lactate dehydrogenase (LDH), which catalyzes the conversion of pyruvate to lactate. Also, PTA was very sensitive to the inhibition by butyric acid. Difference in the specific metabolic rate of xylose at different pHs suggests that the balance in NADH is a key in controlling the metabolic pathway used by the cells in the fermentation.

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Level of enzymes involved in acetate, butyrate, acetone and butanol formation by Clostridium acetobutylicum

Cited by 243 publications

References 17 publications

Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum—evidence from a mathematical model

Coenzyme A-transferase-independent butyrate re-assimilation in Clostridium acetobutylicum—evidence from a mathematical model

Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition

Effect of pH on metabolic pathway shift in fermentation of xylose by Clostridium tyrobutyricum

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