Proteomic Analysis Reveals Complex Metabolic Regulation In Saccharomyces Cerevisiae Cells Against Multiple Inhibitors Stress

In this research, we studied the proteome response of yeast cells cultivated undermultiple inhibitors stress. Toxic compounds including acids, furans, and phenols weregenerated from the pretreatment of lignocellulose. These compounds are toxic to thefermentation microorganism cells, and are usually referred as inhibitors.For the Saccharomyces cerevisiae cells cultivated in a batch mode under AFP(5.3g/L Acetic acid,1.3g/L Furfural, and0.5g/L Phenol) stress for threeindependent cell cultures, and the control group cultivated without AFP inhibitors, wecarried out proteomic analysis of the cells at lag phase and exponential phase,respectively. In proteomic analysis,194and215unique proteins were identified asdifferently expressed proteins at lag phase and exponential phase, respectively.Specifically, when cultivated under AFP stress, the yeast cells co-regulated proteinfolding and protein synthesis process to prevent the generation and aggregation ofmisfolded proteins and to save cellular energy, increased the activity of glycolysis,redirected metabolic flux towards phosphate pentose pathway and the biosynthesis ofethanol instead of the biosynthesis of glycerol and acetic acid, upregulatedoxidoreductases especially at lag phase and induced programmed cell death atexponential phase. For the yeast cells cultivated under AFP stress, the newmetabolism homeostasis in favor of cellular energy and redox homeostasis wasgenerated in the first cell culture under AFP stress, and then inherited and optimizedin the daughter cells, enabling them to respond to AFP stress rapidly and efficiently,which significantly shortened the fermentation time. Yeast mutant strains with singledeletion of genes were used in the verification experiment, and the results verified theconclusions in proteomic analysis.Yeast cells are able to adapt to different culture environments through theregulation of cellular metabolism, and proteomic analysis of yeast tolerancemechanism can provide useful information to further improve the fermentationefficiency of the microorganisms in bioethanol industry.