摘要
为阐明酿酒酵母固醇与耐盐特性的关系,构建麦角固醇合成关键基因ERG3敲除菌株Bs-1;平板验证发现,Bs-1在60 g/L NaCl-酵母浸出粉胨葡萄糖(yeast extract peptone dextrose,YPD)平板上菌落生长被抑制,在80 g/L NaCl-YPD平板上完全不能生长;运用气相色谱-质谱联用检测菌株中固醇的种类和含量,发现Bs-1不能合成麦角固醇,却合成了5,6-二氢麦角固醇。此外,分析Bs-1和野生菌株BY4741的代谢发现,在60 g/L NaCl-YPD中,Bs-1的最大OD600 nm为5.56±0.30,比BY4741降低了45%;Bs-1的最高乙醇产量为(4.20±0.00)g/L,比BY4741降低了35%;在盐胁迫条件下,Bs-1与BY4741相比会产生大量胞外甘油,但细胞对甘油的保留能力却减弱。结果表明酵母中固醇种类的变化影响了细胞代谢特性和细胞膜的流动性,造成细胞胞内甘油外排增加,导致细胞耐盐性降低。
In order to elucidate the relationship between the sterol composition and halotolerance of Saccharomyccs cerevisiae,strain Bs-1 was constructed by knocking out the key gene ERG3 involved in ergosterol synthesis.The growth of Bs-1 was inhibited on YPD(yeast extract,peptone and dextrose)plates containing 60 g/L NaCl as compared with wild type strain BY4741.It was unable to survive on YPD containing 80 g/L.Using gas chromatography-mass spectrometry(GC-MS),we found that Bs-1 could synthesize 5,6-dihydroergosterol rather than ergosterol.In addition,the metabolites of Bs-1 and BY4741 were analyzed.The maximum OD600 nm of Bs-1 was 5.56±0.30 in YPD containing 60 g/L NaCl,which was 45%lower than that of BY4741;the maximum ethanol yield of Bs-1 was(4.20±0.00)g/L,which was 35%lower than that of BY4741;and Bs-1 produced larger amount of extracellular glycerol than did BY4741,but its ability to retain glycerol was weakened.These results indicate that changes in sterol composition could affect metabolic characteristics and membrane fluidity of yeast cells,resulting in increased intracellular glycerol efflux and decreased yeast salt tolerance.
作者
王慧
陈雄
林卫潮
李曜灵
代俊
WANG Hui;CHEN Xiong;LIN Weichao;LI Yaoling;DAI Jun(Key Laboratory of Fermentation Engineering,Ministry of Education,College of Bioengineering and Food Science,Hubei University of Technology,Wuhan 430068,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2020年第8期83-90,共8页
Food Science
基金
国家自然科学基金面上项目(31871789,41876114)。
关键词
酿酒酵母
耐盐性
麦角固醇
ERG3
Saccharomyccs cerevisiae
halotolerant
ergosterol
ERG3