In Situ Analysis of Metabolic Characteristics Reveals the Key Yeast in the Spontaneous and Solid-State Fermentation Process of Chinese Light-Style Liquor
In Situ Analysis of Metabolic Characteristics Reveals the Key Yeast in the Spontaneous and Solid-State Fermentation Process of Chinese Light-Style Liquor
复制标题
原位代谢特征分析揭示清酒自然固态发酵过程中的关键酵母
DOI：
10.1128/aem.04219-13
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发表时间：
2014-06-01
影响因子：
4.4
通讯作者：
Xu, Yan
中科院分区：
文献类型：
--
作者：
Kong, Yu;Wu, Qun;Xu, Yan
摘要对白酒自然发酵过程中酵母菌的原位代谢特性了解较少。采用偏最小二乘回归方法对清香型白酒代谢谱与酵母菌群落的协变性进行了建模。通过对可培养酵母菌26S核糖体DNA(RDNA)D_1/D_2区序列的分析，评价了酵母菌的多样性，并用气相色谱-质谱仪(GC-MS)分析了酒糟中的挥发性化合物。共鉴定出8种酵母菌和58种挥发性化合物。其中16种挥发性化合物的调节与酵母种群的变化有关(预测的准确度为20%)。结果表明，异常毕赤酵母通过对乳酸乙酯、辛酸、十四酸乙酯等几种重要挥发性物质的调节，产生了中国白酒特有的香气。相应地，几乎所有与异常拟青霉相关的化合物都在该酵母菌的纯培养中被检测到。然而，与偏最小二乘回归结果相反，在同一纯培养物中没有检测到乳酸乙酯和异丁酸乙酯，这表明异常拟青霉只有在与其他酵母物种共存的情况下才能产生某些代谢物。此外，不同的酵母群落在发酵谷物中提供了不同的挥发性模式，这导致了所得到的白酒中不同的风味特征。这项研究有助于确定参与自发发酵的关键酵母物种，并提供对单个酵母物种在群落中作用的更深层次的了解。
ABSTRACT The in situ metabolic characteristics of the yeasts involved in spontaneous fermentation process of Chinese light-style liquor are poorly understood. The covariation between metabolic profiles and yeast communities in Chinese light-style liquor was modeled using the partial least square (PLS) regression method. The diversity of yeast species was evaluated by sequence analysis of the 26S ribosomal DNA (rDNA) D1/D2 domains of cultivable yeasts, and the volatile compounds in fermented grains were analyzed by gas chromatography (GC)-mass spectrometry (MS). Eight yeast species and 58 volatile compounds were identified, respectively. The modulation of 16 of these volatile compounds was associated with variations in the yeast population (goodness of prediction [Q 2] > 20%). The results showed that Pichia anomala was responsible for the characteristic aroma of Chinese liquor, through the regulation of several important volatile compounds, such as ethyl lactate, octanoic acid, and ethyl tetradecanoate. Correspondingly, almost all of the compounds associated with P. anomala were detected in a pure culture of this yeast. In contrast to the PLS regression results, however, ethyl lactate and ethyl isobutyrate were not detected in the same pure culture, which indicated that some metabolites could be generated by P. anomala only when it existed in a community with other yeast species. Furthermore, different yeast communities provided different volatile patterns in the fermented grains, which resulted in distinct flavor profiles in the resulting liquors. This study could help identify the key yeast species involved in spontaneous fermentation and provide a deeper understanding of the role of individual yeast species in the community.