Enhancing Saccharomyces cerevisiae reactive oxygen species and ethanol stress tolerance for high-level production of protopanoxadiol. (March 2017)

• Record Type: Journal Article
• Authors: Zhao, Fanglong; Du, Yanhui; Bai, Peng; Liu, Jingjing; Lu, Wenyu; Yuan, Yingjin
• Is Part Of: Bioresource technology. Volume 227(2017)
• Page Start: 308
• Page End: 316
• Publication Date: 2017-03
• Subjects: Saccharomyces cerevisiae -- Cells viability -- ROS tolerance -- Ethanol stress tolerance -- Protopanaxadiol; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2016.12.061
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: A synergistic effect of P450-CPR uncoupling and ethanol stress on ROS releasing was spotted. Cells viability was improved after enhancing ROS and ethanol stress tolerance. PPD production of W3a-ssPy reached to 4.25 g/L in 5 L reactor, which is the highest yield reported. This work made the production of PPD possible by fermentation instead of phytoextraction. 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 84 h. Increased cells viability enables yeast to produce more PPD through feeding additional ethanol. In 5 L fermenter, PPD production of W3a-ssPy reached to 4.25 ± 0.18 g/L (19.48 ± 0.28 mg/L/OD600), which is the highest yield reported so far. This work makes the industrial production of PPD possible by microbial fermentation.