Construction and co-expression of plasmid encoding xylitol dehydrogenase and a cofactor regeneration enzyme for the production of xylitol from D-arabitol.
The biotransformation of D-arabitol into xylitol was investigated with focus on the conversion of D-xylulose into xylitol. This critical conversion was accomplished using Escherichia coli to co-express a xylitol dehydrogenase gene from Gluconobacter oxydans and a cofactor regeneration enzyme gene which was a glucose dehydrogenase gene from Bacillus subtilis for system 1 and an alcohol dehydrogenase gene from G. oxydans for system 2. Both systems efficiently converted D-xylulose into xylitol without the addition of expensive NADH. Approximately 26.91 g/L xylitol was obtained from around 30 g/L D-xylulose within system 1 (E. coli Rosetta/Duet-xdh-gdh), with a 92% conversion yield, somewhat higher than that of system 2 (E. coli Rosetta/Duet-xdh-adh, 24.9 g/L, 85.2%). The xylitol yields for both systems were more than 3-fold higher compared to that of the G. oxydans NH-10 cells (7.32 g/L). The total turnover number (TTN), defined as the number of moles of xylitol formed per mole of NAD(+), was 32,100 for system 1 and 17,600 for system 2. Compared with that of G. oxydans NH-10, the TTN increased by 21-fold for system 1 and 11-fold for system 2, hence, the co-expression systems greatly enhanced the NADH supply for the conversion, benefiting the practical synthesis of xylitol.
State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 210009, PR China.
Peng
P
Zhou
Sha
S
Li
Hong
H
Xu
Xiaohai
X
Feng
Pingkai
P
Ouyang
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D003067:Coenzymes / Q000235:genetics / Q000378:metabolism; D050542:D-Xylulose Reductase / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D005822:Genetic Vectors; D020600:Gluconobacter oxydans / Q000201:enzymology / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013402:Sugar Alcohols / Q000378:metabolism*; D014993:Xylitol / Q000096:biosynthesis*; D014996:Xylulose / Q000378:metabolism
D001426:Bacterial Proteins; D003067:Coenzymes; D011994:Recombinant Proteins; D013402:Sugar Alcohols; D014996:Xylulose; D050542:D-Xylulose Reductase; D014993:Xylitol; C014999:arabitol