水塔老陈醋大曲酵母的分离鉴定及产乙醇和乙酸乙酯特性

Isolation and identification of yeats in Daqu for aged vinegar production and their capacity for producing ethly alcohol and ethly acetate

采用传统分离培养方法,从水塔老陈醋大曲中分离纯化出21株酵母菌,利用26S r DNA D1/D2序列分析方法结合形态学特征,对分离纯化的酵母菌进行鉴定,并用其发酵糯米糖化液,用静态顶空-气质联用的方法测定发酵后乙醇和乙酸乙酯的含量。结果发现:21株酵母菌鉴定结果为2株弗比恩酵母(Cyberlindnera fabianii),8株扣囊复膜酵母(Saccharomycopsis fibuligera)、6株异常威克汉姆酵母(Wickerhamomyces anomalus)、3株葡萄牙棒孢酵母(Clavispora lusitaniae)、2株东方伊萨酵母(Issatchenkia orientalis)。21株菌株发酵后产物乙醇和乙酸乙酯的含量存在较大差别,其中产生乙酸乙酯和乙醇最多的菌株分别为异常威克汉姆酵母m12(含量为4.4415 g/L)和扣囊复膜酵母q25(含量为48.577 g/L);产生最少的则分别为扣囊复膜酵母q6(含量为0.0037 g/L)和东方伊萨酵母q12(含量为11.4555 g/L)。提示老陈醋大曲中不同种类的酵母菌在发酵中对乙醇和乙酸乙酯具有不同的贡献。

Twenty- one yeast strains were isolated from Daqu,a starter participating in fermentation particularly for producing aged vinegar,via conventional yeast culture.The colony and cellular morphological characteristics of the yeasts were observed. The sequence analysis of 26 S r DNA（ D1 / D2 region） from the yeasts was subsequent performed to further identify the strains.The fermentation with each of these yeasts was finally carried out,and ethyl alcohol,as well as ethyl acetate in fermented solution were detected using static headspace- GC- MS for investigation of their function.The results showed that the isolated yeast strains contained 2 Cyberlindnera fabianii,8 Saccharomycopsis fibuligera,6 Wickerhamomyces anomalus,3 Clavispora lusit and 2 Issatchenkia orientalis strains.All isolated yeast strains had capacity to produce ethyl alcohol,but the concentrations were different between the strains. Ethyl acetate was also produced,which concentration was various in different strains. The highest levels of ethyl acetate and ethyl alcohol produced by Wickerhamomyces anomalus m12 and accharomycopsis fibuligera q25 reached 4.4415 g / L and 48.4577 g / L respectively in fermented liquor,while the lowest levels by Saccharomycopsis fibuligera q6 and Issatchenkia orientalis q12 were 0.0037 g / L and 11.4555 g / L.These data indicated that the contribution of the yeast strains in Daqu on producing ethyl alcohol and ethyl acetate for aged vinegar might be different.