Functional exploration of Gordonia in solid-state Baijiu fermentation system

The genus Gordonia, a member of the Actinobacteria phylum, is frequently present in Baijiu fermentation processes, yet its specific impact on Baijiu flavor remains inadequately understood. Three Gordonia strains were isolated from Daqu and pit mud, capable of producing cellulase, acid protease, neutral protease, and esterase enzymes. Through purebred fermentation experiments, it was discovered that Gordonia ajococcus Q1, Gordonia amicalis Q2, and Gordonia amicalis Q3 exhibit notable proficiency in the production of alcohols, acids, and ketones, respectively. In co-fermentation experiment of Gordonia and Daqu, it was found that the inoculation of Gordonia significantly changed the bacterial community structure in the fermented grains, resulting in a notable increase in the variety and quantity of flavor compounds in the Baijiu compared to the control group. Especially, ethyl palmitate content was found to be approximately doubled in the experimental group. Furthermore, strain Q1 contributed to elevated levels of pentanol and butyl hexanoate, strain Q2 increased ethyl hexanoate content by 12.88%, and strain Q3 enhanced the diversity of floral and fruity fragrance compounds in the original Baijiu.