Non-Saccharomyces yeasts enhance yield and flavor in industrial xiaoqu light-flavor baijiu production

This study investigated the effects of adding Saccharomycopsis fibuligera (SF) and Pichia kudriavzevii (PK) on microbial communities and flavor substances in industrial xiaoqu light-flavor baijiu production. The result showed that the highest acidity was found in the control group (CK: Saccharomyces cerevisiae and Rhizopus) at the end of fermentation. SF and PK promoted the growth of Rhizopus while decreasing the abundance of S. cerevisiae during the saccharification stage. Metagenomic sequencing showed that S. cerevisiae and Lactobacillus helveticus were the dominant fungus and bacterium during the late stage of fermentation, and the fungal community tended to be stable before the bacterial community. Notably, the temperature change rate in zaopei (fermented grains) of PK was faster than that in CK and SF, whereas the synthesis of flavor substances was later than that in CK and SF. Moreover, the liquor yield of SF and PK increased by 4.08 % and 4.26 %, respectively. Flavor substance analysis of the base liquor demonstrated that both SF and PK elevated ethyl acetate content and decreased ethyl lactate. Meanwhile, β-phenethyl alcohol, 2,3-butanediol, isoamyl alcohol, and isobutanol contents were increased in SF, and 2,3-butanediol, isoamyl alcohol, and methanol contents were lowest in PK. These findings demonstrate the potential of non-Saccharomyces yeasts for flavor and yield optimization in baijiu production.