一株产2-苯乙醇酵母的鉴定及其在酱油酿造中的应用

2-苯乙醇是酱油的特征香气成分，为研究其合成代谢途径并提高其在酱油发酵醪中的含量，从酱油发酵醪分离筛选到1株产2-苯乙醇酵母菌株30-2；通过形态观察、生理生化试验、转录间隔区（ITS）序列测序和系统进化树分析鉴定菌株30-2为接合酵母（Zygosaccharomyces sp.）；菌株30-2可以在高含盐（18% NaCl）培养基中生长，采用唯一氮源实验证明了菌株30-2主要通过艾氏途径，以苯丙氨酸为底物合成2-苯乙醇。菌株30-2添加至酱油发酵醪可一定程度降低发酵液还原糖含量，2-苯乙醇合成量达到40.95 mg/L，并可以抑制发酵醪产酸，对酱油其他理化指标影响不显著（P＞0.05）；外加苯丙氨酸后2-苯乙醇含量进一步提高到对照组的14.7倍；显示出菌株30-2在高盐发酵调味品风味改善方面的应用前景。

Identification of 2-phenethyl alcohol-producing yeast and its application in soy sauce brewing

2-phenethyl alcohol is a characteristic aroma component of soy sauce. For the purpose of enhancing the production of 2-phenethyl alcohol during soy sauce fermentation, a 2-phenethyl alcohol-producing yeast strain 30-2 was screened from fermented mash of soy sauce. The strain was identified as Zygosaccharomyces sp. by morphologic observation, physiological and biochemical tests, ITS rDNA sequencing and phylogenetic tree analysis. The strain 30-2 was able to grow in a high salt medium (18% NaCl). Sole nitrogen source experiments showed that the strain 30-2 synthesized 2-phenethyl alcohol using phenylalanine as substrate by the Ehrlich pathway. Adding strain 30-2 could reduce reducing sugar content to a certain extent, and produce 40.95 mg/L 2-phenethyl alcohol in the fermented mash of soy sauce. Meanwhile, it was capable of restraining acidic compounds production, and there was no significant effect on other physical and chemical indexes of soy sauce (P＞0.05). After adding phenylalanine, 2-phenethyl alcohol increased to 14.7 times of the control group. This study highlighted the promising potential of strain 30-2 for flavor improvement of high-salt fermented seasonings.