文献类型：期刊文献

英文题名：Design and engineering of whole-cell biocatalyst for efficient synthesis of (R)-citronellal

作者：Zhang, Baoqi[1];Du, Han[1];Zheng, Yanqiu[1];Sun, Jiale[1];Shen, Yu[1];Lin, Jinping[1];Wei, Dongzhi[1]

机构：[1]East China Univ Sci & Technol, New World Inst Biotechnol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2022

卷号：15

期号：5

起止页码：1486

外文期刊名：MICROBIAL BIOTECHNOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000713988300001)】；

基金：This work was supported by the National Key Research and Development Program of China (No. 2021YFC2102100), the Natural Science Foundation of Shanghai (No. 19ZR1412700), the Fundamental Research Funds for the Central Universities (No. 22221818014) and partially supported by the Open Funding Project of the State Key Laboratory of Bioreactor Engineering.

语种：英文

摘要：Bioproduction of optical pure (R)-citronellal from (E/Z)-citral at high substrate loading remains challenging. Low catalytic efficiency of (R)-stereoselective ene reductases towards crude citral mixture is one of the major bottlenecks. Herein, a structure-based engineering strategy was adopted to enhance the catalytic efficiency and stereoselectivity of an ene reductase (OYE2p) from Saccharomyces cerevisiae YJM1341 towards (E/Z)-citral. On basis of homologous modelling, molecular docking analysis and alanine scanning at the binding pocket of OYE2p, a mutant Y84A was obtained with simultaneous increase in catalytic efficiency and stereoselectivity. Furthermore, site-saturation mutagenesis of Y84 yielded seven mutants with improved activity and stereoselectivity in the (E/Z)-citral reduction. Among them, the variant Y84V exhibited an 18.3% and 71.3% rise in catalytic efficiency (k(cat)/K-m) for (Z)-citral and (E)-citral respectively. Meanwhile, the stereoselectivity of Y84V was improved from 89.2% to 98.0% in the reduction in (E/Z)-citral. The docking analysis and molecular dynamics simulation of OYE2p and its variants revealed that the substitution Y84V enabled (E)-citral and (Z)-citral to bind with a smaller distance to the key hydrogen donors at a modified (R)-selective binding mode. The variant Y84V was then co-expressed with glucose dehydrogenase from Bacillus megaterium in E. coli D4, in which competing prim-alcohol dehydrogenase genes were deleted to prevent the undesired reduction in the aldehyde moiety of citral and citronellal. Employing this biocatalyst, 106 g l(-1) (E/Z)-citral was completely converted into (R)-citronellal with 95.4% ee value and a high space-time yield of 121.6 g l(-1) day(-1). The work highlights the synthetic potential of Y84V, which enabled the highest productivity of (R)-citronellal from (E/Z)-citral in high enantiopurity so far.