Enhancing the fermentation of acidified food waste using a self-formulated thermophilic and acid-resistant bacterial agent

Food waste is easy to acidify food waste due to its high content of organic matter. But commercial bacterial agents rarely consider acid resistance as a factor, leading the low fermentation efficiency and poor product quality. In this study, the optimal operation mode of a self-formulated bacterial agent was established, and the fermentation of acidified food waste using our formulation was found to be enhanced in comparison with fermentation using existing commercial bacteria. Response surface methodology (RSM) was used to explore the optimal fermentation conditions of the self-formulated bacterial agent, which was determined to be acid- and high-temperature resistant in our preliminary study. Additionally, using a laboratory simulation experiment of fermenting acidified food waste at a high temperature and in aerobic conditions, the overall superiority of our self-formulated bacterial agent on fermentation was determined in comparison with three types of commercially available microbial agents. RSM results showed that the optimum fermentation conditions were 10% (w/w), medium-level ventilation mode, and temperature-controlled heating. Results of the simulated fermentation experiment showed that compared with commercial bacterial agents, the time required by our formulation to increase the pH to 5.5 could be shortened by more than 5 days and the degradation rate of organic matter could be increased by more than 20%, resulting in the fermentation products meeting the primary maturity with no phytotoxicity requirements (GI>50%). Our self-formulated bacterial agent could significantly improve the aerobic fermentation effect of acidified food waste, highlighting its potential in the use in a real-world setting.