一株低产高级醇桑椹果酒酵母的分离、鉴定

以桑椹为分离源,从其自然发酵醪液中分离得到35株酵母菌,采用杜氏小管发酵法初筛,产乙醇能力复筛,耐乙醇和SO₂能力三级筛选,再与葡萄酒活性干酵母的发酵性能和高级醇产生量进行比较,得到1株发酵性能优良且高级醇产生量低的桑椹果酒酵母—S-2。对S-2菌种进行的研究表明,该菌在12 h开始产气,48 h后产生的气体充满杜氏小管,在14%乙醇和120 mg/L SO₂的胁迫下仍有较好的发酵表现,该菌在正常情况下发酵产生的乙醇含量高达10.56%,且高级醇产生量为312.41 mg/L。采用18S rDNA对其进行序列鉴定,确定其与酿酒酵母(Saccharomyces cerevisiae)同源性最高,相似度达到100%。该菌完全可以取代葡萄酒酵母专门用于桑椹果酒的发酵。

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 18 S 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.