多粮浓香型白酒中特征酵母菌与耐酸乳杆菌的关系

【背景】多菌种协同代谢是浓香型白酒发酵的根本特征之一。【目的】探究多粮浓香型白酒发酵过程中功能微生物菌株间的相互协作关系,为实现发酵过程优化提供理论基础。【方法】采用传统分离培养法获得了多粮浓香型白酒发酵过程中的特征酵母菌和耐酸乳杆菌,并探讨了共培养过程中菌株的相互关系以及主要挥发性代谢产物的变化。【结果】共分离到3株优势特征性酵母菌(KazachstaniahumilisZ1、PichiakudriavzeviiZ2、CandidaethanolicaZ3)和1株耐酸乳杆菌(Lactobacillus acetotolerans W)。K. humilis Z1和L. acetotolerans W共培养体系中耐酸乳杆菌数量明显少于纯培养L. acetotolerans W的菌体数量;3株酵母菌均一定程度抑制L. acetotolerans W产乳酸,K. humilis Z1能抑制L. acetotolerans W不产乳酸;K. humilis Z1纯培养与Z1W共培养体系的挥发性代谢产物的构成相似;纯培养P. kudriavzevii Z2与Z2W共培养体系的挥发性代谢产物差异明显,主要表现为共培养时乙酸乙酯和乳酸乙酯含量显著增加。【结论】在共培养体系条件下,产乙醇酵母菌对耐酸乳杆菌的乳酸代谢有抑制作用,而耐酸乳杆菌又对酵母菌的乙醇代谢有一定影响,这对多粮浓香型白酒品质调控和菌群间相互关系具有重要意义。

Relationship between typical yeasts and Lactobacillus acetotolerans in multi-grain strong aroma Baijiu

Background] Synergetic metabolism of multi-microbial strains is one of the essential feature of fermentation process for Chinese strong aroma Baijiu. Objective] To study the relationship between functional microbial organisms in the fermentation process of multi-grain strong aroma Baijiu, which could provided theoretical references for optimization of fermentation process. Methods] The typical yeasts and Lactobacillus acetotolerans in the fermentation process of multi-grain strong aroma Baijiu were isolated by culture-dependent method, and the relationship between these yeasts and L. acetotolerans strains and variation of major volatile metabolites were also discussed. Results] Three typical yeast strains (Kazachstania humilis Z1, Pichia kudriavzevii Z2, Candida ethanolica Z3) and one Lactobacillus acetotolerans strain (L. acetotolerans W) were isolated. The number of L. acetotolerans W in the co-culture medium of K. humilis Z1 and L. acetotolerans W (Z1&W) was significantly less than that in the single culture medium of L. acetotolerans W. All of three yeast strains could inhibit the lactic acid production ability of L. acetotolerans W, and no lactic acid was produced in co-culture medium of Z1&W. The volatile profile of single Z1 was similar with that in Z1&W. Obvious difference in volatile profile was monitored between single Z2 and Z2&W, in which, concentrations of ethyl acetate and ethyl lactate in Z2&W were significantly increased. Conclusion] Under the condition of co-culture system, ethanol-producing yeast had inhibition effect on lactic acid metabolism of L. acetotolerans, and L. acetotolerans had certain influence on ethanol metabolism of yeast. It was of great significance for the quality control of multi-grain strong aroma Baijiu and its relationship with the microflora.