Isolation and identification of the dominant yeast from fermented grains of Baiyunbian liquor and the analysis of fermentation characteristics

From fermenting packing materials and fermented grains of Baiyunbian liquor,seven yeast strains named as Z1,Z2,Z3,Z4,FJ5,BYB-2,BYB-3 and FJ5 were isolated,respectively.Using 26S rDNA D1/D2 sequence analysis,the results showed that the Z1,Z2,Z3 and FJ5 were Is-satchenkia orientalis,Z4,BYB-2 and BYB-3 were Candida tropicalis,Saccharomyces cerevisiae and Pichia galeiformis(or Pichia manshurica),re-spectively.The results showed that there was a diversity of yeast species in Baiyunbian liquor brewing process,and I.orientalis was the dominant yeast strain.The high temperature resistant,alcohol resistant ability and metabolites of the alcoholic fermentation were measured to the 7 yeast.The results showed that I.orientalis not only had the ability to produce alcohol,but also had resistant to heat and alcohol with high ethyl acetate produc-tion.The results of ethanol fermentation using sorghum as raw material showed that the average yield of ethyl acetate produced by two strains of I.orientalis Z1 and FJ5 reached 204.19mg/L.