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Characterization of an acetoin reductase/2,3-butanediol dehydrogenase from Clostridium ljungdahlii DSM 13528

Tan, Yang, Liu, Zi-Yong, Liu, Zhen, Li, Fu-Li
Enzyme and microbial technology 2015 v.79-80 pp. 1-7
Clostridium acetobutylicum, Clostridium ljungdahlii, Escherichia coli, NADP (coenzyme), acetoin, acetone, alcohol dehydrogenase, batch fermentation, butanol, catalytic activity, ethanol, genes, metabolic engineering, protein content
Acetoin reductase catalyzes the formation of 2,3-butanediol from acetoin. In Clostridium ljungdahlii DSM 13528, the gene CLJU_c23220 encoding the putative Zn²⁺-dependent alcohol dehydrogenase was cloned and expressed in Escherichia coli. The recombinant enzyme, CLAR, can catalyze the conversion of acetoin to 2,3-butanediol with NADPH as the cofactor. Furthermore, the gene CLJU_c23220 was introduced into Clostridium acetobutylicum ATCC 824 and the transformant was conferred the capacity of 2,3-butanediol production. In batch fermentation the transformant produced up to 3.1g/L of 2,3-butanediol, as well as acetone, butanol and ethanol (ABE, 17.8g/L) in amounts similar to those produced by the wild type strain. This study provides conclusive evidence at the protein level that CLJU_c23220 is the key gene responsible for the conversion of acetoin to 2,3-butanediol in C. ljungdahlii DSM 13528. Moreover, the C. acetobutylicum ATCC 824 was modified via one-step metabolic engineering to produce 2,3-butanediol without influencing the ABE production.