Abstract:Vinegar makers in China have suffered from brewing spoilage during high temperature seasons that seriously affects the nutritional composition and quality of vinegar. In order to thoroughly study the high temperature tolerant spoilage microbes, our research team selected five batches of spoilage vinegar samples for microbe isolation and identification and the composition of the gas producing bacterial consortium TYF-LIM-L09 was analyzed by microbial metagenomic sequencing. The TYF-LIM-L09 was then characterized for pH and ethanol tolerance, gas production capacity and activities of core enzymes in glucose metabolism. The results showed that 4 stable bacterial consortium and 46 strains were separated from spoilage vinegar samples, 44 strains of them belonged to the genera Rummeliibacillus, Enterococcus, Vagococcus, Lactobacillus, Bacillus, Staphylococcus, Brevundimonas, Paenibacillus, and the other two isolated strains came from unknown genera. The bacterial consortium TYF-LIM-L09, which had a strong gas-producing ability, could grow well at 50 ℃and had a high ethanol tolerance of 8% (v/v), was composed of more than 6 genera. The produced gas was CO2 and the highest concentration could reach 71.43%(v/v). The pyruvate kinase and pyruvate decarboxylase of TYF-LIM-L09 had relatively high activities. In summary, TYF-LIM-L09 was presumed to be the key microbial contaminant causing vinegar to swell.
