Volatile Fatty Acid Production from Baijiu Distillers' Grains Via Anaerobic Fermentation with Rumen Microbes: Performance and Mechanism.

This study proposes, for the first time, a novel resource utilization approach of Baijiu distiller’s grains for volatile fatty acid (VFA) production via anaerobic fermentation with rumen microbes. Results showed that Baijiu distiller’s grains with light aroma, strong aroma, and soy sauce aroma all exhibited good hydrolysis and VFA production. Removal of volatile solids (VS) reached 28.2%-42.3%, and VFA concentrations reached 5392–7374 mg/L during rumen fermentation of Baijiu distiller’s grains. VFA components consisted of acetate, propionate, butyrate, and isovalerate, with isovalerate accounting for 12.5%-17%. Metagenomic analysis showed that bacterial genera such as Rummeliibacillus, Prevotella, etc. and fungal genera such as Geotrichum, Neocallimastix, etc. were the core genera during hydrolysis and VFA production of Baijiu distiller’s grains. Rich and diverse carbohydrate-active enzymes together guaranteed the hydrolysis of Baijiu distiller’s grains. High expression of functional genes related to hydrolysis and VFA production also corresponded to the high hydrolysis and VFA production. Thus, Baijiu distiller’s grains are suitable as substrates for VFA production with rumen microbes. This study provides a new idea for the high-value utilization of Baijiu distiller’s grains, and deepened the mechanism of rumen fermentation of biomass waste.