Efficient production of D-1,2,4-butanetriol from D-xylose by engineered Escherichia coli whole-cell biocataiysts

摘要

We have developed a whole-cell bioconversion system for the production ofD-1,2,4-butanetriol (BT)from renewable biomass.A plasmid pETduet-xylB-yjhG-T7- adhP-T7-mdlC was constructed and transformed to Escherichia coli BL21(DE3)to obtain the whole cells of E.coli BL2I-XYMA capable of bioconversion D-xylose to BT.Then,the factors including carbon sources,nitrogen sources,metal ions,and culture conditions (pH,temperature,IPTG)were identified,and their effects on the wholecell activity for BT production were investigated.To obtain the highest whole-cell activity,the optimal cultivation parameters are:15g·L^-1 yeast extract,5g·L^-1 sucrose, 3g·L^-1 KH2PO4,5g·L^-1 NaCl,3g·L^-1 NH4Cl,0.25g·L^-1 MgSO4·7H2O and 1mL·L^-1 the mixture of trace elements.With the optimized whole cells of E.coli BL21-XYMA,60g·L^-1 of xylose was converted to 28g·L^-1 BT with a molar yield of 66%,which is higher than those reported in the biotechnological system.