Isolation and Identification of a Low Yield Higher Alcohols Yeast Strain for Mulberry Wine

A total of 35 yeast strains were isolated from natural fermented mash of mulberries. With duchenne tubular screening,alcohol yield ability screening,alcohol and SO₂ resistance ability screening,these strains were compared with two wine active dry yeast strains in terms of fermenting property and higher alcohols yield. S-2 strain was screened out as an excellent mulberry wine yeast strain in terms of fermenting property and low yield higher alcohols. The S-2 strain began to produce gas at 12 h,and the gas produced after 48 h was filled with duchenne tubules. Under the stress of 14% alcohol and 120 mg/L SO₂,it still had good fermentation performance. Under normal conditions,the alcohol content produced by S-2 strain was as high as 10.56%,and the yield of higher alcohols was 312.41 mg/L. The 18S rDNA sequence amplification was conducted for molecular biology identification of S-2 and it turned out to have the highest degree of match (100%) with Saccharomyces cerevisiae. S-2 strain could replace wine yeast trains to specifically use for mulberry wine fermentation.