Levels of enzymes involved in the synthesis of acetate from CO2 in Clostridium thermoautotrophicum

Clark, J. E.; Ragsdale, S.W.; Ljungdahl, Lars G.; Wiegel, Juergen

doi:10.1128/jb.151.1.507-509.1982

Cited by 51 publications

(7 citation statements)

References 22 publications

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“…S. sucromutans was shown to contain all of the enzyme activities of the Wood pathway necessary for metabolism of C1 compounds on THF carriers ( Table 3). The specific activities of the enzymes were in the range expected from former studies of Clostridium thermoaceticum (5), C. formicoaceticum (26), Acetobacterium woodii (30), and C. thermoautotrophicum (9); this was especially so when these bacteria were grown under heterotrophic conditions. Formyl-THF synthetase had higher specific activity in crude extracts of cells grown with cellobiose and vanillin than with those grown with cellobiose and formate; it has been previously shown that extracts of cells of species that can use formate have higher specific activities for formyl-THF synthetase when formate is not present in the growth medium.…”

Section: Discussionsupporting

confidence: 65%

Metabolism of One-Carbon Compounds by the Ruminal Acetogen Syntrophococcus sucromutans

Doré

Bryant

1990

Appl Environ Microbiol

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Syntrophococcus sucromutans is the predominant species capable of 0 demethylation of methoxylated lignin monoaromatic derivatives in the rumen. The enzymatic characterization of this acetogen indicated that it uses the acetyl coenzyme A (Wood) pathway. Cell extracts possess all the enzymes of the tetrahydrofolate pathway, as well as carbon monoxide dehydrogenase, at levels similar to those of other acetogens using this pathway. However, formate dehydrogenase could not be detected in cell extracts, whether formate or a methoxyaromatic was used as electron acceptor for growth of the cells on cellobiose. Labeled bicarbonate, formate, [1-'4C] pyruvate, and chemically synthesized O-[methyl-_4C]vanillate were used to further investigate the catabolism of one-carbon (C1) compounds by using washed-cell preparations. The results were consistent with little or no contribution of formate dehydrogenase and pointed out some unique features. Conversion of formate to CO2 was detected, but labeled formate predominantly labeled the methyl group of acetate. Labeled CO2 readily exchanged with the carboxyl group of pyruvate but not with formate, and both labeled CO2 and pyruvate predominantly labeled the carboxyl group of acetate. No CO2 was formed from 0 demethylation of vanillate, and the acetate produced was position labeled in the methyl group. The fermentation pattern and specific activities of products indicated a complete synthesis of acetate from pyruvate and the methoxyl group of vanillate.

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Section: Discussionsupporting

confidence: 65%

Metabolism of One-Carbon Compounds by the Ruminal Acetogen Syntrophococcus sucromutans

Doré

Bryant

1990

Appl Environ Microbiol

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“…Many methanogens possess CO dehydrogenase (1). High levels of CO dehydrogenase also occur in acetogens (2)(3)(4)(5)(6)(7). In the case of hydrogen-utilizing methanogens (8-10) and acetogenic bacteria (11,12) CO dehydrogenase may be essential for the anabolic fixation of C02 into cell carbon.…”

Section: Introductionmentioning

confidence: 99%

Behavior of carbon monoxide as a trace component of anaerobic digester gases and methanogenesis from acetate

Hickey¹,

Switzenbaum²

1990

Environ. Sci. Technol.

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Carbon monoxide was a normal trace component of the gases produced during anaerobic sludge digestion. The CO concentration increased in response to perturbing the digestion process by increasing organic loading or adding acetate. Reducing the headspace methane level resulted in higher measured CO concentrations. Accordingly, a thermodynamic relationship was developed by dividing the acetoclastic methane reaction into two half-cell reactions, representing production of and subsequent oxidation of CO. A constant fraction of the total free energy available for acetate conversion to methane was assigned to each half-cell based on the basis of experimental observations. It was determined that approximately 54% of the energy available for acetate conversion to methane was consistently associated with the anaerobic oxidation of CO to carbon dioxide. Estimated values compared well for measured concentrations for both mesophilic and thermophilic digesters operating under steady-state conditions. The thermodynamic relationship, based upon gaseous components only, was manipulated to accurately predict acetate concentration in a digester system subjected to an organic overload that was monitored with an on-line data acquisition system.

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“…Subsequently, methyl-THF cyclohydrolase (FCH) cyclizes the formyl-group linked to THF to generate a methenyl intermediate, and methylene-THF is finally converted by methylene-THF dehydrogenase (MDH). In M. thermoacetica , cyclohydrolase and dehydrogenase function as a single bifunctional protein complex, whereas Clostridium formicoaceticum ( Clark et al, 1982 ) and A. woodii ( Ragsdale and Ljungdahl, 1984 ) have monofunctional proteins. In particular, when converting methenyl-THF to methylene-THF, two electrons are used and transferred by either NADH or NADPH depending on the species ( Moore et al, 1974 ; Ragsdale and Ljungdahl, 1984 ).…”

Section: Understanding Physiology and Metabolism Of Acetogensmentioning

confidence: 99%

Engineering Acetogenic Bacteria for Efficient One-Carbon Utilization

et al. 2022

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C1 gases, including carbon dioxide (CO2) and carbon monoxide (CO), are major contributors to climate crisis. Numerous studies have been conducted to fix and recycle C1 gases in order to solve this problem. Among them, the use of microorganisms as biocatalysts to convert C1 gases to value-added chemicals is a promising solution. Acetogenic bacteria (acetogens) have received attention as high-potential biocatalysts owing to their conserved Wood–Ljungdahl (WL) pathway, which fixes not only CO2 but also CO. Although some metabolites have been produced via C1 gas fermentation on an industrial scale, the conversion of C1 gases to produce various biochemicals by engineering acetogens has been limited. The energy limitation of acetogens is one of the challenges to overcome, as their metabolism operates at a thermodynamic limit, and the low solubility of gaseous substrates results in a limited supply of cellular energy. This review provides strategies for developing efficient platform strains for C1 gas conversion, focusing on engineering the WL pathway. Supplying liquid C1 substrates, which can be obtained from CO2, or electricity is introduced as a strategy to overcome the energy limitation. Future prospective approaches on engineering acetogens based on systems and synthetic biology approaches are also discussed.

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Levels of enzymes involved in the synthesis of acetate from CO2 in Clostridium thermoautotrophicum

Cited by 51 publications

References 22 publications

Metabolism of One-Carbon Compounds by the Ruminal Acetogen Syntrophococcus sucromutans

Metabolism of One-Carbon Compounds by the Ruminal Acetogen Syntrophococcus sucromutans

Behavior of carbon monoxide as a trace component of anaerobic digester gases and methanogenesis from acetate

Engineering Acetogenic Bacteria for Efficient One-Carbon Utilization

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