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Resolving the TCA cycle and pentose‐phosphate pathway of Clostridium acetobutylicum ATCC 824: Isotopomer analysis, in vitro activities and expression analysis
Author(s) -
Crown Scott B.,
Indurthi Dinesh C.,
Ahn Woo Suk,
Choi Jungik,
Papoutsakis Eleftherios T.,
Antoniewicz Maciek R.
Publication year - 2011
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201000282
Subject(s) - clostridium acetobutylicum , pentose phosphate pathway , pentose , biochemistry , chemistry , isotopomers , clostridium , in vitro , biology , enzyme , fermentation , glycolysis , bacteria , butanol , organic chemistry , genetics , ethanol , molecule
Solventogenic clostridia are an important class of microorganisms that can produce various biofuels. One of the bottlenecks in engineering clostridia stems from the fact that central metabolic pathways remain poorly understood. Here, we utilized the power of 13 C‐based isotopomer analysis to re‐examine central metabolic pathways of Clostridium acetobutylicum ATCC 824. We demonstrate using [1,2‐ 13 C]glucose, MS analysis of intracellular metabolites, and enzymatic assays that C. acetobutylicum has a split TCA cycle where only Re ‐citrate synthase (CS) contributes to the production of α‐ketoglutarate via citrate. Furthermore, we show that there is no carbon exchange between α‐ketoglutarate and fumarate and that the oxidative pentose‐phosphate pathway (oxPPP) is inactive. Dynamic gene expression analysis of the putative Re ‐CS gene (CAC0970), its operon, and all glycolysis, pentose‐phosphate pathway, and TCA cycle genes identify genes and their degree of involvement in these core pathways that support the powerful primary metabolism of this industrial organism.