Abstract: In this work, the physicochemical properties of fermented grains for Fenjiu sampled at different time points of fermentation were evaluated, and the fungal community structure in it was analyzed by high-throughput sequencing. A comparative analysis was performed between the samples from primary and secondary fermentation. The results showed that the major nutrients and microbial metabolites in fermented grains changed regularly during the fermentation process. Significantly different trends in these compounds were observed between primary and secondary fermentation. Totally 98 fungal operational taxonomic units (OTUs) were obtained from fermented grains, and the diversity of fungi was significantly different between primary and secondary fermentation. The diversity of fungi increased first and then decreased in primary fermentation, while the diversity of fungi gradually decreased in secondary fermentation. The initial fungal communities in primary and secondary fermentation were similar to each other. Pichia was the dominant strain for both fermentation processes. However, the dominant fungi at the later stage of fermentation were quite different between them. Saccharomyces cerevisiae was the most dominant fungus in primary fermentation, and Candida was the most dominant fungus in secondary fermentation. The results from this study are of great significance to further study the metabolic pathway for key flavor substances and to improve the yield and quality of Fenjiu.

Key words: Fenjiu; fermented grains; fungi; high-throughput sequencing