Yang Fan, Liu Zhi-Cheng, Wang Xue, Li Li-Li, Yang Lan, Tang Wen-Zhu, Yu Zhi-Min, Li Xianzhen
School of Biological Engineering, Dalian Polytechnic University, Dalian, 116034, PR China.
Microb Cell Fact. 2015 Apr 17;14:59. doi: 10.1186/s12934-015-0243-3.
Invertase Suc2 was recently identified as a key hydrolase for inulin catabolism in Saccharomyces cerevisiae, whereas the Suc2 activity degrading inulin varies greatly in different S. cerevisiae strains. The molecular mechanism causing such variation remained obscure. The aim of this study is to investigate how Suc2 activity is regulated in S. cerevisiae.
The effect of SUC2 expression level on inulin hydrolysis was investigated by introducing different SUC2 genes or their corresponding promoters in S. cerevisiae strain BY4741 that can only weakly catabolize inulin. Both inulinase and invertase activities were increased with the rising SUC2 expression level. Variation in the promoter sequence has an obvious effect on the transcript level of the SUC2 gene. It was also found that the high expression level of SUC2 was beneficial to inulin degradation and ethanol yield.
Suc2-mediated inulin catabolism is regulated at transcript level in S. cerevisiae. Our work should be valuable for engineering advanced yeast strains in application of inulin for ethanol production.
蔗糖酶Suc2最近被鉴定为酿酒酵母中菊粉分解代谢的关键水解酶，然而，不同酿酒酵母菌株中降解菊粉的Suc2活性差异很大。造成这种差异的分子机制仍不清楚。本研究的目的是探究酿酒酵母中Suc2活性是如何被调控的。
通过在只能微弱分解菊粉的酿酒酵母菌株BY4741中引入不同的SUC2基因或其相应启动子，研究了SUC2表达水平对菊粉水解的影响。随着SUC2表达水平的升高，菊粉酶和蔗糖酶活性均增加。启动子序列的变化对SUC2基因的转录水平有明显影响。还发现SUC2的高表达水平有利于菊粉降解和乙醇产量。
在酿酒酵母中，Suc2介导的菊粉分解代谢在转录水平上受到调控。我们的工作对于构建用于菊粉生产乙醇的先进酵母菌株具有重要价值。
