Efficient production of xylitol by the integration of multiple copies of xylose reductase gene and the deletion of Embden–Meyerhof–Parnas pathway-associated genes to enhance NADPH regeneration in Escherichia coli. (1st August 2019)

• Record Type: Journal Article
• Authors: Yuan, Xinsong; Wang, Jiping; Lin, Jianping; Yang, Lirong; Wu, Mianbin
• Is Part Of: Journal of industrial microbiology & biotechnology. Volume 46:Number 8(2019)
• Page Start: 1061
• Page End: 1069
• Publication Date: 2019-08-01
• Subjects: Xylitol -- Hemicellulosic hydrolysate -- CRISPR/Cas9 -- Multicopy integration -- Cofactor regeneration; Industrial microbiology -- Periodicals; 660.62
• DOI: 10.1007/s10295-019-02169-3
• Languages: English
• ISSNs: 1367-5435

Abstract

Abstract: Cofactor supply is a rate-limiting step in the bioconversion of xylose to xylitol. Strain WZ04 was first constructed by a novel simultaneous deletion–insertion strategy, replacing ptsG, xylAB and ptsF in wild-type Escherichia coli W3110 with three mutated xylose reductase genes ( xr ) from Neurospora crassa . Then, the pfkA, pfkB, pgi and/or sthA genes were deleted and replaced by xr to investigate the influence of carbon flux toward the pentose phosphate pathway and/or transhydrogenase activity on NADPH generation. The deletion of pfkA / pfkB significantly improved NADPH supply, but minimally influenced cell growth. The effects of insertion position and copy number of xr were examined by a quantitative real-time PCR and a shake-flask fermentation experiment. In a fed-batch fermentation experiment with a 15-L bioreactor, strain WZ51 produced 131.6 g L −1 xylitol from hemicellulosic hydrolysate (xylitol productivity: 2.09 g L −1 h −1 ). This study provided a potential approach for industrial-scale production of xylitol from hemicellulosic hydrolysate.