Effects of NADH availability on the Klebsiella pneumoniae strain with 1,3-propanediol operon over-expression.

Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, China.
Journal of Basic Microbiology (Impact Factor: 1.2). 06/2012; DOI: 10.1002/jobm.201100580
Source: PubMed

ABSTRACT It is generally known that genes dha B and dha T are responsible for 1,3-propanediol (1,3-PD) production in the presence of glycerol in Klebsiella pneumoniae and these genes are organized in one operon. In the present study, a genetic means of increasing the enzyme activities of 1,3-PD formation pathway through the over-expression of 1,3-PD opeorn was performed in K. pneumoniae S6. The recombinant strain S6-PD showed 27- and 15-fold increase in enzymatic activities of DhaB and DhaT, respectively with respect to wild-type strain while failed to improve the 1,3-PD yield due to the inadequacy of cofactor NADH. Therefore, in order to increase NADH availability, a NADH regeneration system was constructed by heterologous expression of NAD(+) -dependent formate dehydrogenase gene (fdh 1) from Candida boidinii and introduced into S6-PD to investigate its effects on the glycerol utilization and 1,3-PD formation. The results demonstrated that the increase of NADH availability could efficiently improve glycerol metabolism and promote 1,3-PD yield. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

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May 20, 2014