文献类型：期刊文献

英文题名：Enhancing the bioconversion of phytosterols to steroidal intermediates by the deficiency of kasB in the cell wall synthesis of Mycobacterium neoaurum

作者：Xiong, Liang-Bin[1,2];Liu, Hao-Hao[2];Zhao, Ming[2];Liu, Yong-Jun[2];Song, Lu[2];Xie, Zhi-Yong[2];Xu, Yi-Xin[3];Wang, Feng-Qing[2];Wei, Dong-Zhi[2]

机构：[1]Shanghai Univ Med & Hlth Sci, Shanghai Key Lab Mol Imaging, Shanghai, Peoples R China;[2]East China Univ Sci & Technol, Newworld Inst Biotechnol, State Key Lab Bioreactor Engn, Shanghai, Peoples R China;[3]Shanghai Univ Med & Hlth Sci, Coll Pharm, Shanghai, Peoples R China

年份：2020

卷号：19

期号：1

外文期刊名：MICROBIAL CELL FACTORIES

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000528036800001)】；

基金：This work was supported by the National Natural Science Foundation of China (Nos. 81830052, 31370080), the construction project of Shanghai Key Laboratory of Molecular Imaging (18DZ2260400), Shanghai Municipal Education Commission (Class II Plateau Disciplinary Construction Program for Medical Technology of SUMHS, 2018-2020), the Training Subsidy Scheme of Young Teachers in Colleges and Universities of Shanghai (No. ZZJKYX19011) and the Hundred Teachers' Bank of Shanghai University of Medicine and Health Sciences.

语种：英文

外文关键词：Mycolic acids; Self-enhancement conversion; beta-Ketoacyl-acyl carrier protein synthase; Phytosterol; Steroid intermediates

摘要：Background: The bioconversion of phytosterols into high value-added steroidal intermediates, including the 9 alpha-hydroxy-4-androstene-3,17-dione (9-OHAD) and 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC), is the cornerstone in steroid pharmaceutical industry. However, the low transportation efficiency of hydrophobic substrates into mycobacterial cells severely limits the transformation. In this study, a robust and stable modification of the cell wall in M. neoaurum strain strikingly enhanced the cell permeability for the high production of steroids. Results: The deletion of the nonessential kasB, encoding a beta-ketoacyl-acyl carrier protein synthase, led to a disturbed proportion of mycolic acids (MAs), which is one of the most important components in the cell wall of Mycobacterium neoaurum ATCC 25795. The determination of cell permeability displayed about two times improvement in the kasB-deficient strain than that of the wild type M. neoaurum. Thus, the deficiency of kasB in the 9-OHAD-producing strain resulted in a significant increase of 137.7% in the yield of 9 alpha-hydroxy-4-androstene-3,17-dione (9-OHAD). Ultimately, the 9-OHAD productivity in an industrial used resting cell system was reached 0.1135 g/L/h (10.9 g/L 9-OHAD from 20 g/L phytosterol) and the conversion time was shortened by 33%. In addition, a similar self-enhancement effect (34.5%) was realized in the 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC) producing strain. Conclusions: The modification of kasB resulted in a meaningful change in the cell wall mycolic acids. Deletion of the kasB gene remarkably improved the cell permeability, leading to a self-enhancement of the steroidal intermediate conversion. The results showed a high efficiency and feasibility of this construction strategy.