Analysis of bacterial diversity of Chinese Luzhou-flavor liquor brewed in different seasons by Illumina Miseq sequencing

Luzhou-flavor liquor is one of the most popular liquors in China, produced by the distillation of Zaopei, a mixture of fermented and fresh cereals. The quality and flavor of Luzhou-flavor liquor are closely related to the multitudinous bacteria in Zaopei. Little is known about the effect of brewing seasons, a main operating parameter, on the bacterial diversity of Zaopei. In this study Illumina Miseq sequencing platform was first applied to study the bacterial succession in Zaopei during liquor fermentation processes in winter and summer. The research results showed that 10 phyla and 13 families were detected in Zaopei. Differences in bacterial communities of summer and winter Zaopei were apparent. Proteobacteria was the most abundant phylum in winter Zaopei. However, bacteria belonging to Firmicutes were most frequently detected in summer Zaopei. The diverse genera decreased sharply at the first half of the 40-day fermentation stage, and then bacterial population were mainly represented by Acetobacter and Lactobacillus both in winter and summer Zaopei. Interestingly, the summer Zaopei contained significantly higher proportions of LAB and lower proportions of Acetobacter than winter Zaopei. Clustering analysis also revealed that bacterial community structure was distinct between the Zaopei fermented in the two seasons. Thermoactinomycetaceae, Prevotella, Alcaligenes, and Gluconacetobacter not previously identified in Zaopei were revealed in this study by high-throughput sequencing. This study might be helpful in achieving better control over the quality of Luzhou-flavor liquor brewed in different seasons.