Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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The sulfur metabolism during Acetogenesis and Solventogenesis of Clostridium acetobutylicum

ABSTRACT: The batch fermentation of Clostridium acetobutylicum is characterized by an acetogenic growth phase during exponential growth when mainly acetate and butyrate are fermentation products. Then, at the end of exponential growth and during stationary phase, the organism switches to solventogenic growth and large amounts of acetone, ethanol and butanol are produced. These growth phases can be studied independent from each other in a phosphate-limited continuous culture. In transcription analysis of continuous cultures using DNA microarrays it became evident that, among others, operons involved in sulfur assimilation are strongly up-regulated during solventogenesis. Using the ClosTron technique we constructed two knock-out mutants in the genes CAC0105 and CAC0930 annotated as involved in sulfate reduction and cysteine biosynthesis. Complementation experiments were carried out with sulfite and cysteine to prove the predicted function. The fermentation experiments of wild type and mutants using phosphate-limited and sulfur-limited continuous culture demonstrated that less sulfur source was consumed in solventogenic phase and the efficiency of cysteine uptake became lower. DNA microarrays were performed to study the difference of transcriptional expression when the wild type was challenged with insufficient sulfur source and the mccB (CAC0930) mutant was inactivated in the continuous culture. The result provided insights into understanding the sulfur metabolism regulatory.

ORGANISM(S): Clostridium acetobutylicum ATCC 824

SUBMITTER: ziyong liu

PROVIDER: E-MTAB-2745 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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The sulfur metabolism during Acetogenesis and Solventogenesis of Clostridium acetobutylicum

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