文献类型：期刊文献

英文题名：The Inhibitory Effect of Cyclodextrin on Oxygen Bioavailability Is a Key Factor for the Metabolic Flux Redistribution Toward Steroid Alcohols in Phytosterol Resting Cells Bioconversion

作者：Wang, Xue-Dong[1];Chen, Kuan[1];Cao, Dan-Dan[1];Wei, Dong-Zhi[1]

机构：[1]East China Univ Sci & Technol, New World Inst Biotechnol, State Key Lab Bioreactor Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2021

卷号：193

期号：8

起止页码：2443

外文期刊名：APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY

收录：;EI(收录号：20211110081338);WOS:【SCI-EXPANDED(收录号:WOS:000628485100001)】；

基金：This work was supported by the National Natural Science Foundation of China (31570079, 21276083).

语种：英文

外文关键词：Hydroxypropyl-β -cyclodextrin; Mycobacterium; Oxygen bioavailability; Steroid alcohol; Redox balance

摘要：In the present work, we tried to identify the mechanism why by which the steroid alcohols accumulated when hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was present to enhance the sterol conversion rate. Compared with the bioconversion system without HP-beta-CD, the reaction rate was greatly improved in presence of HP-beta-CD, but the steroid alcohols largely accumulated concurrently. In a reaction system with an enhanced reaction rate, the higher intracellular NADH/NAD(+) level was detected, and the production of steroid alcohols increased also. Mycobacterium neoaurum mutants with higher KshA activity (3-ketosteroid 9 alpha-hydrolase, a monooxygenase hydroxylating the nucleus at C-9 at the expense of NAD(P)H consumption) reduced the steroid alcohol production, and in the meantime, the NADH/NAD(+) level was decreased consequently. Further research found that oxygen availability was seriously inhibited by the cyclodextrin in a reaction system. These results indicated that NADH formed in the bioconversion was not properly regenerated via the respiratory chain because of the poor oxygen bioavailability. The inhibitory effect of cyclodextrin on oxygen bioavailability is a key factor for the metabolic flux redistribution toward steroid alcohols in phytosterol resting cells bioconversion.