Saccharomyces cerevisiae is the most important industrial microorganism used to fuel ethanol production worldwide. Herein, we obtained a mutant S. cerevisiae strain with improved capacity for ethanol fermentation, from 13.72% (v/v for the wild-type strain) to 16.13% (v/v for the mutant strain), and analyzed its genomic structure and gene expression changes. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealed that the changed genes were mainly enriched in the pathways of carbohydrate metabolism, amino acid metabolism, metabolism of cofactors and vitamins, and lipid metabolism. The gene expression trends of the two strains were recorded during fermentation to create a timeline. Venn diagram analysis revealed exclusive genes in the mutant strain. KEGG enrichment of these genes showed upregulation of genes involved in sugar metabolism, mitogen-activated protein kinase pathway, fatty acid and amino acid degradation, and downregulation of genes involved in oxidative phosphorylation, ribosome, fatty acid and amino acid biogenesis. Protein interaction analysis of these genes showed that glucose-6-phosphate isomerase 1, signal peptidase complex subunit 3, 6-phosphofructokinase 2, and trifunctional aldehyde reductase were the major hub genes in the network, linking pathways together. These findings provide new insights into the adaptive metabolism of S. cerevisiae for ethanol production and a framework for the construction of engineered strains of S. cerevisiae with excellent ethanol fermentation capacity.
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