Microbial community in vinasse liquid during processing of vinasse fish

In order to discuss the microbial community diversity of vinasse liquid during processing of vinasse fish, the large yellow croaker (Larimichthys crocea) was chosen as a material to produce vinasse fish with traditional pickling technology, and the bacterial flora of vinasse liquid was measured by Illumina HiSeq2500 high-throughput sequencing technique. The results showed that the pH value slightly increased in the first 5 or 10 days and then gradually decreased with different salt dosage (2%, 5% and 10%). The TVB-N value was all lower than 30 mg/100 g after 30 days of processing and the lowest value was found in 5% salt group. The variation of the pH and TVB-N value in the 5% salt group were basically the same in different ratios of fish to vinasse (1∶1, 1∶1.5 and 1∶2), which indicated that the quality of this vinasse fish was stable during processing. High-throughput sequencing results of 5% salt group showed that the Chao index of the vinasse liquid of 1∶2 was the largest (167), which indicated the highest community richness. The Shannon index of the vinasse liquid of 1∶1 was the largest (2.75) and the Simpson index was the lowest (0.109), which indicated the highest bacterial diversity. The main microbial domains of the vinasse liquid involve 17 phyla, 1 unclassified phylum and 143 genera. Proteobacteria, Cyanobacteria and Firmicutes were dominant, of which Proteobacteria was absolutely dominant. Vibrio, Chloroplast norank and Enterobacter were dominant, and Vibrio was absolutely dominant in the early fermentation. The results could provide theoretical basis for the study of microbial community diversity of vinasse fish liquid and references for the control of hygienic safety of drunk aquatic products.