乙酰辅酶A合成代谢对酿酒酵母生理功能的影响  

Effect of acetyl-CoA synthase gene overexpression on physiological function of Saccharomyces cerevisiae

作　　者：陈孚江[1] 周景文[2] 史仲平[1,3] 刘立明[1,2] 堵国成[2] 陈坚[2,3] 

机构地区：[1]江南大学食品科学与技术国家重点实验室,无锡214122 [2]江南大学工业生物技术教育部重点实验室,无锡214122 [3]江南大学生物工程学院,无锡214122

出　　处：《微生物学报》2010年第9期1172-1179,共8页Acta Microbiologica Sinica

基　　金：国家自然科学基金重点项目(20836003);国家自然科学基金(20706025);国家“863计划”(2006AA10Z313);霍英东教育基金项目(11075)~~

摘　　要：【目的】研究酿酒酵母（Saccharomycesc erevisiae）中乙酰辅酶A合成酶基因ACS1和ACS2的生理作用。【方法】将来源于S.cerevisiae的ACS1和ACS2分别进行过量表达,研究过量表达ACS1和ACS2后S.cerevisiae胞内乙酰辅酶A含量、ATP水平、甲羟戊酸途径转录和乙醇耐受性等生理学特性变化。【结果】与出发菌株相比,过量表达ACS1和ACS2使得：（1）胞内乙酰辅酶A含量提高了2.19倍（ACS1）和5.02倍（ACS2）;（2）胞内ATP含量提高了3.93倍（ACS1）和2.05倍（ACS2）;（3）甲羟戊酸途径8个关键基因表达量显著上调;（4）S.cerevisiae对乙醇胁迫抵御能力显著增强。过量表达ACS1对乙醇胁迫的耐受能力强于过量表达ACS2。【结论】增加胞内乙酰辅酶A的含量可以显著增加甲羟戊酸途径碳代谢流量,并增强S.cerevisiae对发酵过程主要副产物乙醇的耐受能力。【Objective】The aim of our work is to investigate the effects of overexpression of two acetyl-CoA synthase genes,ACS1 and ACS2,on the physiological functions of Saccharomyces cerevisiae.【Methods】We overexpressed ACS1 and ACS2 in S.cerevisiae CEN.PK2 with shuttle vector pY26-TEF-GPD.We determined and compared the physiological parameters of the parent strain to the ACS1/2 overexpressed strains,including the intracellular acetyl-CoA content,ATP content,mevalonate pathway,and the tolerance to ethanol stress.【Results】Compared to the parent strain,the overexpression of ACS1 and ACS2 led to：（1）The intracellular acetyl-CoA content increased by 2.19-fold（ACS1） and 5.02-fold（ACS2）,respectively;（2）The intracellular ATP content increased by 3.92-fold（ACS1） and 2.05-fold（ACS2）,respectively;（3）The transcription levels of the seven key genes in mevalonate pathway were upregulated,therefore,more carbon flux was channeled into the mevalonate pathway,which could provide precursor for terpenes synthesis;（4）The tolerance to high content of ethanol was enhanced,especially for the ACS1 overexpression strain.【Conclusion】The results presented here demonstrated that the overexpression of acetyl-CoA synthase can enhance the carbon flux into mevalonate pathway and improve the tolerance of S.cerevisiae to high content of ethanol,which is the main byproduct of the fermentation process with the yeast.

关 键 词：酿酒酵母 乙酰辅酶A 乙酰辅酶A合成酶 乙醇抗性 甲羟戊酸途径 

分 类 号：TS261.11[轻工技术与工程—发酵工程]