Effects of NADH availability on the Klebsiella pneumoniae strain with 1,3-propanediol operon over-expression.
It is generally known that genes dhaB and dhaT 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 (fdh1) 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.
Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Sciences, China Jiliang University, Hangzhou, Zhejiang Province, China.
Zheng
Z
Ma
Xuping
X
Shentu
Yalin
Y
Bian
Xiaoping
X
Yu
D002175:Candida / Q000201:enzymology / Q000235:genetics; D005560:Formate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005990:Glycerol / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D060847:Metabolic Engineering; D009243:NAD / Q000378:metabolism*; D009876:Operon; D011409:Propylene Glycols / Q000378:metabolism*
C499417:FDH1 protein, Candida; D005656:Fungal Proteins; D011409:Propylene Glycols; D009243:NAD; C041787:1,3-propanediol; D005560:Formate Dehydrogenases; D005990:Glycerol