Effect of co-culture of Acetobacter and Lactobacillus strains on growth and metabolism of the key functional microbes during Zhenjiang aromatic vinegar fermentation

Abstract:

[Objective] To better explain the metabolic mechanism of microbial community during Zhenjiang vinegar fermentation, we studied the interaction between Acetobacter and Lactobacillus, the key functional microorganisms during multispecies solid-state acetic acid fermentation. [Methods] Here, two strains of Acetobacter and eight strains of Lactobacillus isolated from vinegar fermentation culture, namely, Acetobacter pasteurianus G3-2, A. pomorum G15-6, Lactobacillus paracasei E1-1, L. helveticus M3-1, L. reuteri GE7-1, L. plantarum M10-1, L. fermentum M10-3, L. casei E10-1, L. pontis M17-5, L. hilgardii M3-4, were selected for microbial growth and metabolism analysis in monoculture and coculture fermentation. We compared the differences of interaction types between in vitro fermentation and in situ fermentation, then GC-MS was used to analyze the effects of interaction on the flavor of Zhenjiang vinegar. [Results] Synergistic effect between A. pasteurianus G3-2 and L. helveticus M3-1, L. plantarum M10-1, L. pontis M17-5 and L. reuteri GE7-1 in vitro fermentation and in situ fermentation was identified. Negative effect between A. pomorum G15-6 and L. paracasei E1-1, however, A. pomorum G15-6 showed different effects on L. plantarum M10-1, L. pontis M17-5 and L. reuteri GE7-1 in vitro fermentation and in situ fermentation. Coculture of A. pasteurianus G3-2 and L. helveticus M3-1, L. reuteri GE7-1 showed better performance in 2,3-butanedione, valeric acid, ethyl acetate and octyl formate production than monoculture, and the yield of 2,3-butanedione increased from none detected to 9.87 mg/L and 14.28 mg/L. [Conclusion] The interaction between Lactobacillus and Acetobacter in Cupei can affect the changes of main metabolites and volatile substances. This work provides a theoretical basis for in-depth analysis of the brewing mechanism of Zhenjiang vinegar, lays the foundation for rational regulation of the microbial community and improving the flavor and quality of Zhenjiang vinegar.