Meng Xing, Wu Qun, Wang Li, Wang Diqiang, Chen Liangqiang, Xu Yan
State Key Laboratory of Food Science and Technology; The Key Laboratory of Industrial Biotechnology, Ministry of Education; Synergetic Innovation Center of Food Safety and Nutrition; School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
Technical Center of Maotai Co. Ltd., Renhuai, 564501, Guizhou, China.
J Ind Microbiol Biotechnol. 2015 Dec;42(12):1601-8. doi: 10.1007/s10295-015-1647-0. Epub 2015 Sep 1.
Microbial interactions could impact the metabolic behavior of microbes involved in food fermentation, and therefore they are important for improving food quality. This study investigated the effect of Bacillus licheniformis, the dominant bacteria in the fermentation process of Chinese Maotai-flavor liquor, on the metabolic activity of Saccharomyces cerevisiae. Results indicated that S. cerevisiae inhibited the growth of B. licheniformis in all mixed culture systems and final viable cell count was lower than 20 cfu/mL. Although growth of S. cerevisiae was barely influenced by B. licheniformis, its metabolism was changed as initial inoculation ratio varied. The maximum ethanol productions were observed in S. cerevisiae and B. licheniformis at 10(6):10(7) and 10(6):10(8) ratios and have increased by 16.8 % compared with single culture of S. cerevisiae. According to flavor compounds, the culture ratio 10(6):10(6) showed the highest level of total concentrations of all different kinds of flavor compounds. Correlation analyses showed that 12 flavor compounds, including 4 fatty acids and their 2 corresponding esters, 1 terpene, and 5 aromatic compounds, that could only be produced by S. cerevisiae were significantly correlated with the initial inoculation amount of B. licheniformis. These metabolic changes in S. cerevisiae were not only a benefit for liquor aroma, but may also be related to its inhibition effect in mixed culture. This study could help to reveal the microbial interactions in Chinese liquor fermentation and provide guidance for optimal arrangement of mixed culture fermentation systems.
微生物相互作用会影响参与食品发酵的微生物的代谢行为，因此对改善食品质量具有重要意义。本研究考察了中国酱香型白酒发酵过程中的优势细菌地衣芽孢杆菌对酿酒酵母代谢活性的影响。结果表明，在所有混合培养体系中，酿酒酵母均抑制了地衣芽孢杆菌的生长，最终活菌数低于20 cfu/mL。虽然地衣芽孢杆菌对酿酒酵母的生长几乎没有影响，但其代谢会随着初始接种比例的变化而改变。酿酒酵母和地衣芽孢杆菌在接种比例为10(6):10(7)和10(6):10(8)时乙醇产量最高，与酿酒酵母单培养相比提高了16.8%。根据风味化合物分析，接种比例10(6):10(6)时所有不同种类风味化合物的总浓度最高。相关性分析表明，12种风味化合物，包括4种脂肪酸及其2种相应的酯、1种萜类化合物和5种芳香族化合物，这些化合物只能由酿酒酵母产生，它们与地衣芽孢杆菌的初始接种量显著相关。酿酒酵母的这些代谢变化不仅有利于白酒香气形成，还可能与其在混合培养中的抑制作用有关。本研究有助于揭示中国白酒发酵过程中的微生物相互作用，并为混合培养发酵体系的优化配置提供指导。
