Multivariate insights into the effects of inoculating thermophilic aerobic bacteria on the biodegradation of food waste: Process properties, organic degradation and bacterial communities

Food waste (FW) biodegradation by microbial augmentation is an emerging approach for FW treatment. In this study, microbial agent composed of six dominant thermophilic aerobic bacteria identified as Geobacillus lituanicus, Geobacillus kaustophilus, Geobacillus thermoparaffinivorans, Geobacillus caldoxylosilyticus, Bacillus smithii and Acinetobacter pittii was used to enhance the degradation of organic matter in FW during thermophilic aerobic biodegradation process. The results showed that the volatile solid removal (VSR) was 58.42% in experimental group inoculated with the microbial agent, while it was only 16.56% in control group without inoculation. Furthermore, the correlation analysis among physicochemical properties, enzyme activities and bacterial communities, as well as the metabolic function prediction indicated the dominant strains, especially Geobacillus, enhanced FW biodegradation mainly by secreting more lipase and amylase and inducing greater levels of carbohydrate, lipid, nucleotide, cofactors and vitamins metabolism. This study provides a novel method to promote the FW degradation efficiency and new insights into FW biodegradation with thermophilic aerobic bacteria.