Significance and Impact of the Study: Micro-organism is one of the main factors of Moutai-flavour Daqu as a starter. Studying the dynamic changes and differences of micro-organisms in the storage process of Moutai-flavour Daqu in different seasons (spring, summer and autumn) can understand the impact of season and storage time on the micro-organisms in Daqu, which can more scientifically guide the production of Daqu (clarify the storage time in different season), and finally improve the production capacity and quality of Daqu.

Abstract

The quality of Moutai-flavour Baijiu is highly dependent on Moutai-flavour Daqu (MTDQ), which needs to be stored for 6 months before using. It brings abundant bacterium, which can metabolize various enzymes and favour compounds. But the reasonable storage time of MTDQ prepared in different seasons is still uncertain. To this end, the study revealed a detailed bacterial profile of storage MTDQ prepared in three different seasons (specifically, they were stored start from spring, summer and autumn) by using high-throughput sequencing approach (next generation sequencing). Results showed that major phyla of storage MTDQ were Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes and Fusobacteria. The advantages of Firmicutes were Thermoactinomyces and Bacillaceae. Significant differences in bacterial community structures of MTDQ from different seasons and storage time were observed. Compared with summer and autumn MTDQ, the decrease of Thermoactinomyces and increase of Desmospora in spring MTDQ were the main differences and bacterial community structures of summer and autumn MTDQ were more similar. The variation trends of the bacteria community indicated that the effective time of storage period was appropriately 6 months for spring MTDQ, 2 months for summer MTDQ and more than 6 months for autumn MTDQ. These results showed that the length of storage time was associated with the season and it is reasonable to adjust the storage time of MTDQ with the season.