title: Efficient production of xylitol from hemicellulosic hydrolysate using engineered Escherichia coli.
abstract: A metabolically engineered Escherichia coli has been constructed for the production of xylitol, one of the top 12 platform chemicals from agricultural sources identified by the US Department of Energy. An optimal plasmid was constructed to express xylose reductase from Neurospora crassa with almost no inclusion bodies at relatively high temperature. The phosphoenolpyruvate-dependent glucose phosphotransferase system (ptsG) was disrupted to eliminate catabolite repression and allow simultaneous uptake of glucose and xylose. The native pathway for D-xylose catabolism in E. coli W3110 was blocked by deleting the xylose isomerase (xylA) and xylulose kinase (xylB) genes. The putative pathway for xylitol phosphorylation was also blocked by disrupting the phosphoenolpyruvate-dependent fructose phosphotransferase system (ptsF). The xylitol producing recombinant E. coli allowed production of 172.4 g L(-1) xylitol after 110 h of fed-batch cultivation with an average productivity of 1.57 g L(-1) h(-1). The molar yield of xylitol to glucose reached approximately 2.2 (mol xylitol mol(-1) glucose). Furthermore, the recombinant strain also produced about 150 g L(-1) xylitol from hemicellulosic sugars in modified M9 minimal medium and the overall productivity was 1.40 g L(-1) h(-1), representing the highest xylitol concentration and productivity reported to date from hemicellulosic sugars using bacteria. Thus, this engineered E. coli is a candidate for the development of efficient industrial-scale production of xylitol from hemicellulosic hydrolysate.
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: bolysu@gmail.com.
authors.forename: Buli
authors.initials: B
authors.lastname: Su
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: wumb@zju.edu.cn.
authors.forename: Mianbin
authors.initials: M
authors.lastname: Wu
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: 979987841@qq.com.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: linjp@zju.edu.cn.
authors.forename: Jianping
authors.initials: J
authors.lastname: Lin
authors.affiliation: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: lryang@zju.edu.cn.
authors.forename: Lirong
authors.initials: L
authors.lastname: Yang
mesh_terms: D000449:Aldehyde Reductase / Q000235:genetics; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D060847:Metabolic Engineering; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry; D014993:Xylitol / Q000096:biosynthesis*
chemical_list: D011134:Polysaccharides; D012333:RNA, Messenger; C007916:hemicellulose; D000449:Aldehyde Reductase; D014993:Xylitol
keywords: Hemicellulosic hydrolysate; Metabolic engineering; Translation initiation rate; Xylitol; Xylose reductase; mRNA secondary structures