Increasing Galactose Utilized Ability of Saccharomyces cerevisiae Through Gene Engineering

Abstract

Abstract Saccharomyces cerevisiae is capable of fermenting galactose into ethanol, but the productivity from galactose is much lower than those from glucose. An effective approach is undertaken to improve galactose utilized ability and ethanol productivity through gene engineering of the regulatory network controlling the expression of the GAL genes. The GAL gene regulatory network of S. cerevisiae is a tightly regulated system. Gal6, Gal80, and Mig1 are three known negative regulators of the GAL system. In this paper, Gal6, Gal80, and Mig1 were knockout by the way of homologous recombination. This led to a 76 % increase in specific galactose uptake rate compared with the wild-type strain. And the ethanol yield has advanced greatly. Further study showed that GAL80 and MIG1 played more important roles in galactose fermentation of S. cerevisiae than GAL6 did.KeywordsGalactose MIG1 GAL80 GAL6 Saccharomyces cerevisiae