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Effects of NADH availability on the Klebsiella pneumoniae strain with 1,3‐propanediol operon over‐expression
Author(s) -
Ma Zheng,
Shentu Xuping,
Bian Yalin,
Yu Xiaoping
Publication year - 2013
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201100580
Subject(s) - operon , 1,3 propanediol , klebsiella pneumoniae , glycerol , formate dehydrogenase , strain (injury) , cofactor , nad+ kinase , biochemistry , enzyme , propanediol , microbiology and biotechnology , heterologous expression , dehydrogenase , biology , heterologous , alcohol dehydrogenase , chemistry , gene , recombinant dna , escherichia coli , organic chemistry , anatomy
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.