Succession Law and Metabolic Characteristics of Lentibacillus daqui During Stacking Fermentation

Abstract:

[Objective] This study aims to understand the succession and metabolic characteristics of Lentibacillus daqui (L.daqui) in fermented grains during stacking fermentation.[Method] The bacterial community structure in fermented grains during stacking fermentation was analyzed by amplicon sequencing. The effects of raw materials, oxygen content, and culture temperature on the biomass, enzyme production, and aroma production of L. daqui ZS110521T were evaluated by the pure culture solid-state fermentation method. [Result] L. daqui ZS110521T was the dominant genus (relative abundance>10%) in the bacterial community in the early stage (0~60 h) of stacking fermentation. The results of pure culture showed that L. daqui ZS110521T had higher biomass and enzyme activity in the wheat medium, while more pyrazines were accumulated in the sorghum-wheat (mass ratio of 1? ∶ 1) mixed medium. Under aerobic conditions, the enzyme activity and pyrazine content of the strain was higher. The gene copies reached the highest when the strain was cultured at 37~45 ℃ for 36 h, and the enzyme activity was the strongest when the strain was cultured at 45~55 ℃. When the strain was cultured at 65 ℃ for 120 h, 2,5-dimethylpyrazine, 2,4-di-tert-butylphenol, benzaldehyde, nonanal, and acetoin were mainly accumulated. [Conclusion] This study provided a scientific basis for clarifying the enzyme production and aroma production functions of L. daqui ZS110521T in stacking fermentation.