Multi-omics elucidation of resource allocation for enhanced ethanol production via precise glucose control in anaerobic Saccharomyces cerevisiae fermentation

Ethanol, a high-demand clean energy source, is primarily produced via fed-batch fermentation in industrial settings. Although our previous study identified an optimal glucose concentration of 30 g/L for maximal ethanol yield, the mechanisms underlying glucose-dependent cellular adaptation remain unclear. Here, we performed an integrated multi-omics analysis, including transcriptomics, proteomics, metabolomics, and fluxomics, to compare yeast cells under glucose-controlled and uncontrolled conditions. Our results indicate that high glucose stress triggers the regulation of transporters with different affinities and the upregulation of heat shock proteins (HSPs), trehalose, and amino acids. In contrast, protein turnover was reduced under glucose-controlled conditions, suggesting more efficient resource allocation. This metabolic reallocation enhances carbon flux through glycolysis, potentially providing additional energy and NADH to support biomass growth and ethanol production. These findings advance our understanding of yeast regulatory mechanisms under glucose stress and provide insights for metabolic engineering and process optimization.