Abstract: The structure and abundance of the microbial community in samples collected from different production stages of Chishui sun-dried vinegar including herbal Qu, alcoholic fermentation, acetic acid fermentation and sun-dried fermented grains were detected by high-throughput sequencing. The results showed that the sequencing depth effectively covered all microbial species in the samples. The dominant bacterial genera of herbal Qu were Bacillus, Streptomyces and Thermoactinomyces, and the dominant fungal genera were Aspergillus and Thermomyces. During alcoholic fermentation, the dominant bacterial genus was Lactobacillus and the dominant fungal genera were Aspergillus and Thermomyces. The dominant bacterial genera were Lactobacillus and Acetobacter, and the dominant fungal genera were Aspergillus and Trichosporon during acetic acid fermentation. Sun-dried fermented grains had the greatest number of microbial species with uniform relative abundance distribution, and there were no absolutely dominant bacteria and fungi in this stage. The relative abundances of Bacillus, Thermoactinomyces, Proteus, Gluconacetobacter and Rhodococcus were higher than those of other bacterial genera identified, and the relative abundances of Aspergillus, Cladosporium, Sterigmatomyces, Acremonium and Alternaria were higher than those of other fungal genera identified. Clustering heat map analysis and β diversity showed that the microbial community structure in the first three stages basically did not change, while that in the last one significantly varied among samples from the same batch, which may related to the presence of salt and lack of oxygen in the jar. The microbial community structure in the stages of alcoholic fermentation and acetic fermentation was similar to each other, but was significantly different from that in the other two stages, indicating that the microbial community structure in the former these two stages is continuous due to environmental similarity.

Key words: Chishui sun-dried vinegar; microbial community structure; high-throughput sequencing