Bioresource Technology, Vol.261, 196-205, 2018
Enhanced bioreduction synthesis of ethyl (R)-4-chloro-3-hydroybutanoate by alkalic salt pretreatment
In this study, biomass-hydrolysate was used for enhancing the bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE). Firstly, dilute alkalic salt pretreatment was attempted to pretreat bamboo shoot shell (BSS). It was found that enzymatic in situ hydrolysis of 20-50 g/L BSS pretreated with dilute alkalic salts (0.4% Na2CO3, 0.032% Na2S) at 7.5% sulfidity by autoclaving at 110 degrees C for 40 min gave sugar yields at 59.9%-73.5%. Moreover, linear relationships were corrected on solid recovery-total delignification-sugar yield. In BSS-hydrolysates, xylose and glucose could promote the reductase activity of recombinant E. coli CCZU-A13. Compared with glucose, hydrolysate could increase the reductase activity by 1.35-folds. Furthermore, the cyclohexane-hydrolysate (10: 90, v/v) biphasic media containing ethylene diamine tetraacetic acid (EDTA, 40 mM) and L-glutamine (150 mM) was built for the effective biosynthesis of ethyl (R)-4-chloro-3-hydroxybutanoate [(R)-CHBE] (94.6% yield) from 500 mM COBE. In conclusion, this strategy has high potential for the effective biosynthesis of (R)-CHBE (> 99% e.e.).
Keywords:Alkalic salt pretreatment;E. coli CCZU-A13;Ethyl (R)-4-chloro-3-hydroxybutanoate;Ethyl 4-chloro-3-oxobutanoate;Hydrolysate