The stress of bioactive compounds on microbes in anaerobic digestion of food waste and mitigation strategies: A critical review

Energy recovery from food waste (FW) through anaerobic digestion (AD) is an attractive disposal method for FW management and the utilization of sustainable fuel. Nevertheless, bioactive compounds from food, such as food flavoring agents (e.g., salt, capsaicin, allicin, spices, and herbs), food preservative (e.g., sodium benzoate, sorbate, and chitosan), natural flavors compounds (e.g., fruit flavors and tea polyphenols), and mycotoxins and related fungi, could accompany FW into AD systems and cause the instability in long-term AD. This review addressed the impacts of bioactive compounds from FW on AD. The potential microbial response mechanisms of bioactive compounds stress on AD were also elucidated. Furthermore, the mitigation strategies for bioactive compounds stress on AD were proposed in terms of co-digestion, pretreatment, external osmotic pressure, the addition of conductive materials, and dynamic microbiome disassembly and evolution response. This review aimed to provide a better understanding of the fates and environmental risks of FW concomitant with bioactive compounds and to stimulate new mitigation strategy based on microbial response mechanisms in AD systems.