title: Enhancing Saccharomyces cerevisiae reactive oxygen species and ethanol stress tolerance for high-level production of protopanoxadiol.
abstract: Protopanaxadiol (PPD) is an active compound in Panax ginseng. Recently, an optimized PPD synthesis pathway contained a ROS releasing step (a P450-type PPD synthase, PPDS) was introduced into Saccharomyces cerevisiae. Here reported a synergistic effect of PPDS-CPR (CPR, cytochrome P450 reductase) uncoupling and ethanol stress on ROS releasing, which reduced cells viability. To build a robust strain, a cell wall integrity associated gene SSD1 was high-expressed to improve ethanol tolerance, and ROS level decreased for 24.7%. Then, regulating the expression of an oxidative stress regulation gene YBP1 decreased 75.2% of ROS releasing, and improved cells viability from 71.3±1.3% to 88.3±1.4% at 84h. Increased cells viability enables yeast to produce more PPD through feeding additional ethanol. In 5L fermenter, PPD production of W3a-ssPy reached to 4.25±0.18g/L (19.48±0.28mg/L/OD600), which is the highest yield reported so far. This work makes the industrial production of PPD possible by microbial fermentation.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
authors.forename: Fanglong
authors.initials: F
authors.lastname: Zhao
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Du
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300350, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Bai
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300350, PR China. Electronic address: wenyulu@tju.edu.cn.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Lu
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; Key Laboratory of System Bioengineering (Tianjin University), Ministry of Education, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300350, PR China.
authors.forename: Yingjin
authors.initials: Y
authors.lastname: Yuan
mesh_terms: D005285:Fermentation; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D012502:Sapogenins / Q000138:chemical synthesis* / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D012502:Sapogenins; C062916:protopanaxadiol
keywords: Cells viability; Ethanol stress tolerance; Protopanaxadiol; ROS tolerance; Saccharomyces cerevisiae