A synergistic promotion during anaerobic digestion of food waste generated from catering industry by the bio-abiotic additives——Biogas production efficiency and corresponding microbial dynamic changes

The aim of this study was to solve the problem of unstable process induced by low methane production rate, acid accumulation and ammonia inhibition in the anaerobic digestion of floatable-oil recovered food waste (FORFW) generated from the catering industry. Based on our previous research that combined bio-abiotic addition could enhance the anaerobic digestion of food waste synergistically, a three factors-three levels orthogonal experiment of mesophilic anaerobic digestion was conducted in this study to investigate and optimize reaction parameters, including inoculum ratio, iron addition amount and yeast amount. The intrinsic microbial mechanism of synergistic promotion of bio-abiotic additives in FORFW methanogenesis was elucidated by the high throughput sequencing technique. It was found that the influence of three parameters on the methane yield of FORFW anaerobic digestion: inoculum ratio > yeast amount > iron addition amount. The optimal condition were inoculation ratio of 1.5, iron addition of 0.5% (w/w) and activated yeast of 3%(w/w). Under the optimal condition, the VS removal rate of FORFW was 40.1%, and the accumulative methane yield was 237.5mL/g VS. The relative abundance of genera Methanosaeta, Syntrophomonas, and Syner-01 increased significantly in the system, resulting in efficient conversion of lactic acid-derived propionic acid. Genus Methanosaeta interacted with Anaerolineaceae in syntrophic methanogenesis, Syntrophomonas was involved in butyric acid oxidation process, while Syner-01 participated in acetic acid oxidation and amino acid oxidation. Thus, the methane yield of the FORFW generated from the catering industry was ensured. The research results will provide scientific guidance for further practical application and process control. © 2023 Chinese Society for Environmental Sciences. All rights reserved.