一株高产β-苯乙醇酵母菌的分离及产香特性研究

Isolation of a yeast with high-yield forβ-phenylethanol and its aroma characteristics

β-苯乙醇是白酒中的一种重要的香气成分和香气前体物质,提高其浓度有利于丰富白酒的香气层次。该文通过从贾湖高温堆积酒醅中分离纯化筛选获得1株高产β-苯乙醇的毕赤酵母。经鉴定该菌株为库德里阿兹威(氏)毕赤酵母(Pichia kudriavzevii)。通过考查温度、pH、L-苯丙氨酸(L-phenylalanine,L-Phe)、碳源、氮源等单因素变量对β-苯乙醇合成的影响,结合正交试验确定了最优转化培养基和发酵条件,从而大幅提高β-苯乙醇发酵水平至(3.74±0.084)g/L,比优化前提高了86.07%。采用气质联用仪分析该酵母发酵后的挥发性风味物质,结果表明该菌株能合成苯乙醇、乙酸苯乙酯、2-苯乙基-环己烷-1,3-二酮等多种对白酒品质有重要贡献的风味物质,说明该产香特性有利于其在白酒酿造中的进一步应用。

β-phenylethanol is an important aroma component and aroma precursor in Chinese Baijiu,increasing its concentration is beneficial to enrich the aroma level of Chinese Baijiu.A highβ-phenylethanol producing strain was screened by isolation and purification from Jiahu high-temperature stacking fermented grains.The strain was identified as Pichia kudriavzevii.Theβ-phenylethanol production conditions including temperature,pH,L-Phe,carbon source,nitrogen source was optimized using a single factor step-by-step method and orthogonal experimental design.Under the optimal conditions,theβ-phenylethanol yield reached(3.74±0.084)g/L,representing an increase of 86%compared with the initial production.A total of 26 volatile compounds were detected by GC-MS,includingβ-phenylethanol,phenylethyl acetate,and 2-phenethyl-cyclohexane-1,3-dione,which are important for the quality of Baijiu.These characteristics are conducive to its further application in Baijiu brewing.