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.