Analysis And Regulation Of Proteomics Related Antioxidation In Brewer's Yeast

Brewer's yeast is one of the key factors in beer brewing.However,the oxygen stress can affect activity of brewer's yeast,resulting in the decline of beer quality.High antioxidant activity of brewer's yeast can effectively reduce the damage caused by oxygen stress.Understanding the global regulation mechanism of brewer's yeast in antioxidant process will guide the selection of excellent brewer's yeast suitable for industrial production,and provide new insights for exploring the antioxidant mechanism of brewer's yeast and improving its antioxidant activity.In this reaserch,the high antioxidant activity brewer's yeast,which can be used in industrial production and has good generational stability,was screened by Tadpoling method.The two strains with different antioxidant performance were compared and analyzed from the proteomic level,and the key proteins affecting the antioxidant capacity of brewer's yeast were determined.Through the overexpression in Pilsner,the recombinant strains was constructed to further verify the role of key proteins in improving the antioxidant capacity of brewer's yeast.The main results are as follows:By H₂O₂ treatment and domestication process,P-127 was obtained from Pilsner which is a typical Lager type brewer's yeast.Compared with the Pilsner and other mutants,P-127 had lower intracellular ROS change rate?increased about 2.3 times?under ROS stress and higher intracellular ATP level during the whole growth process.In addition,all fermentation indexes of P-127 were normal.Compared with P-127 and Pilsner proteomic data,DEPs mainly affected 275 biological processes,41 cell components and 164 molecular functions,which resulted in the global regulation of brewer's yeast.Improving the structure and function of mitochondria,enhancing the expression of antioxidant related enzymes and anaerobic metabolism,accelerating the metabolism and transportation of glucose and amino acids plays a positive role in improving the antioxidant capacity of brewer's yeast.Genes coding 19 key proteins were overpressed.The results showed that the overexpression of AAC1,ACS1,ADY2 and DNM1 related to mitochondria significantly affected the antioxidant capacity of brewer's yeast;the overexpression of HXT3,HXT4 and HXT7 related to sugar transport promoted the antioxidant capacity of brewer's yeast in a way independent of intracellular ROS and endogenous ATP;the overexpression of LYS20 and AGP1 related to amino acid metabolism and transport increased the H₂O₂ resistance of brewer's yeast,promoted the intracellular ROS balance,but had little effect on the intracellular energy metabolism.Moreover,the overexpression of ALA1 was not conducive to the antioxidant process of brewer's yeast.