Regulation of ethanol production from anaerobic fermentation of food waste using aromatic alcohol-based quorum-sensing molecules

Quorum-sensing molecules (QSMs) are used to regulate microbial metabolites to effectively improve food waste anaerobic fermentation to produce high-value products of ethanol and lactic acid. In this study, low concentrations (25 and 50 μmol/L) of aromatic alcohol favored the synthesis of ethanol and lactic products. Among the aromatic alcohol QSMs, 50 μmol/L of tyrosol enhanced the yield of products. The correlations between substrate composition indicators confirmed that tyrosol was conducive to the anaerobic fermentation of food waste. The regulation mechanism of tyrosol, such as microbial diversity in anaerobic fermentation, was analyzed from the perspective of microbial ecology. The result revealed that tyrosol increased the microbial diversity in the system. Limosilactobacillus, Weissella, and Pediococcus were the dominant bacterial species in the early stages of fermentation, whereas Clostridiaceae and Bacillus were dominant in the later stages. Meanwhile, the main dominant fungal species were Saccharomyces, Aspergillus, and Pichia. The results of this study show that using QSMs, including tyrosol, to regulate the physiological characteristics of anaerobic fermentation microorganisms, promote the synthesis of cell metabolites, and regulate the diversity and succession of microbial communities is a feasible measure. This approach improves the resource utilization efficiency of anaerobic fermentation technology for food waste, which is significant for promoting sustainable development.