Effects of Temperature on Bacterial Community Structure and Ester Generation of Fermenting Grains During Fermentation of a Maotai-flavor Chinese Liquor

Abstract

To study the effect of temperature on the bacterial community structure and ester generation of fermentation of a Maotai-flavored Chinese liquor, grains were fermented anaerobically at 25 °C, 30 °C, 35 °C, 40 °C, and 45 °C, respectively. The results of high-throughput sequencing and statistical analysis showed that temperature had an influence on the bacterial community structure and the diversity index of the fermenting grains. The relative abundance of some bacterial genera in fermenting grains varied greatly with temperature. The diversity index of the bacterial community structure of the fermenting grains generally increased with temperature. In the early stages of fermentation (within 20 days), temperature had a significant influence on bacterial community structure and on the diversity index of the fermenting grains, while at the last stage of fermentation (after 20 days), temperature had a lesser effect. Ester determination results showed that temperature had a significant influence on the ester generation of fermenting grains. Low temperature was beneficial for generating total esters, ethyl acetate, ethyl butyrate, and ethyl caproate, whereas a high temperature was beneficial for generating ethyl lactate in the fermenting grains. The results of a correlation analysis showed that at different temperatures, the species and quantity of bacteria having a significant correlation regarding ester generation were very different.