Project description:The microbial community and enzymes in fermented rice using defined microbial starter, containing Rhizopus oryzae, Saccharomycopsis fibuligera, Saccharomyces cerevisiae and Pediococcus pentosaceus, play an important role in quality of the fermented rice product and its biological activities including melanogenesis inhibitory activity. The microbial metaproteome revealed large-scale proteins expressed by the microbial community to better understand the role of microbiota in the fermented rice.
Project description:Highland barley liquor is a distilled spirit made from highland barley on the Tibetan Plateau, but its alcohol yield is limited by the high fiber content of the raw material. In the field of biomass resources, functional microorganisms are commonly used in pretreatment to degrade cellulose and other substances, improving fermentation output. In this study, we isolated the cellulose-degrading probiotic Lactobacillus delbrueckii GR-8 (CMCase 6.21 U/mL) from the traditional vegetable-based fermented food "Jiangshui" and applied biological pretreatment to the fermentation of highland barley liquor. During pretreatment, probiotics enhanced cellulase and amylase activities in the fermented grains, resulting in a 25% reduction in cellulose content and a 112% increase in free reducing sugar content. The pretreatment significantly altered the microbial community structure, enhancing microbial diversity. After distillation, alcohol yield increased by 3.5%, and total acid and ester contents rose by 25% and 23%, respectively. Pyrazine compounds increased by 1290%, while higher alcohols like nonanol, phenylethanol, and hexanol decreased. The treated liquor caused less harm to mice, who showed improved memory, motor skills, and lower oxidative liver damage. This study demonstrates that biological pretreatment enhances both fermentation and the quality of Chinese spirits.