Li Qun, Zhang Long, Li Rui, Tang Jie, Lin Bin, Qin Chunyu, Jiang Wei, An Longxu, Zhang Fan, Shi Xingxing, Yang Shengzhi, Yang Qiang, Chen Shenxi
Hubei Key Laboratory of Quality and Safety of Traditional Chinese Medicine and Health Food, Jing Brand Co., Ltd., Daye, China.
Guangxi Tianlongquan Wine Industry Co., Ltd., Luocheng, China.
Front Bioeng Biotechnol. 2025 Aug 5;13:1638716. doi: 10.3389/fbioe.2025.1638716. eCollection 2025.
This study aimed to explore the microbial contribution to flavor compound production by analysing the succession patterns and metabolic functional characteristics of microbial communities during preparation, saccharification, and fermentation processes of rice-flavor Baijiu (RFB). The physicochemical parameters during RFB fermentation were systematically monitored, and the volatile flavor profile was characterized using headspace solid-phase microextraction gas chromatography‒mass spectrometry (HS-SPME-GC-MS). Concurrently, metagenomic sequencing was employed to elucidate the microbial community structure and its temporal dynamics throughout the fermentation process. The results of the physicochemical parameters revealed that the reducing sugar content peaked at the end of saccharification and subsequently decreased throughout fermentation, whereas the total acid and total ester contents progressively increased, reaching maximum levels at the fermentation endpoint and maintaining stability. HS-SPME-GC-MS analysis revealed 84 volatile flavor compounds including phenylethanol, ethanol, dimethyl ether, isopentyl alcohol, and acetic acid. Notably, compounds such as L-ethyl lactate, diethyl succinate, and isobutanol were initially synthesized during saccharification and subsequently accumulated during fermentation, emerging as major flavor constituents. Ascomycota and Mucoromycota dominated the fungal community (average relative abundance >1%), whereas Firmicutes and Proteobacteria prevailed among the bacterial phyla. Six genera, , , , , , and were identified as primary contributors to flavor production during fermentation. Functional analysis revealed that microbial metabolism in fermented mash primarily involved amino acid and carbohydrate metabolism, with glycoside hydrolases (GHs) and glycosyl transferases (GTs) serving as key carbohydrate-active enzymes. This study could improve the comprehensive understanding of the brewing mechanism of RFB and provide a theoretical basis for the development and utilization of microbial resources in the fermented grains and the improvement of RFB quality.
本研究旨在通过分析米香型白酒（RFB）制备、糖化和发酵过程中微生物群落的演替模式和代谢功能特征，探讨微生物对风味化合物产生的贡献。系统监测了RFB发酵过程中的理化参数，并采用顶空固相微萃取气相色谱-质谱联用仪（HS-SPME-GC-MS）对挥发性风味特征进行了表征。同时，利用宏基因组测序阐明了整个发酵过程中微生物群落结构及其时间动态变化。理化参数结果表明，还原糖含量在糖化结束时达到峰值，随后在整个发酵过程中下降，而总酸和总酯含量逐渐增加，在发酵终点达到最高水平并保持稳定。HS-SPME-GC-MS分析共鉴定出84种挥发性风味化合物，包括苯乙醇、乙醇、二甲醚、异戊醇和乙酸。值得注意的是，如L-乳酸乙酯、琥珀酸二乙酯和异丁醇等化合物在糖化过程中开始合成，随后在发酵过程中积累，成为主要风味成分。子囊菌门和毛霉门在真菌群落中占主导地位（平均相对丰度>1%），而厚壁菌门和变形菌门在细菌门类中占优势。六个属，即[此处原文缺失六个属的具体名称]，被确定为发酵过程中风味产生的主要贡献者。功能分析表明，发酵醪中的微生物代谢主要涉及氨基酸和碳水化合物代谢，糖苷水解酶（GHs）和糖基转移酶（GTs）是关键的碳水化合物活性酶。本研究有助于提高对RFB酿造机制的全面理解，并为发酵谷物中微生物资源的开发利用及RFB品质提升提供理论依据。
