Low-Temperature Pretreatment (LT-PT) of Food Waste as a Strategy to Enhance Biomethane Production

Food waste (FW) management remains a critical challenge within the circular economy framework. This study examines low-temperature pretreatment (LT-PT) of food waste and its effects on physicochemical transformations and microbial community dynamics. Artificial food waste (AFW) was subjected to LT-PT at 60 °C for 24 h, 48 h, and 72 h to assess changes in organic matter solubilization, nitrogen and phosphorus transformations, microbial composition, and biomethane potential. The results show that LT-PT promotes volatile fatty acid (VFA) accumulation, ammonification, and organic matter solubilization, thereby enhancing substrate biodegradability. The largest VFA increase was observed for acetate, whose concentration increased by approximately 0.55 g/L between 0 h and 72 h of LT-PT. Metagenomic analysis revealed a pronounced shift in microbial communities, with fermentative bacteria (Leuconostocaceae) increasing to 53.08% after 24 h of LT-PT, while Cyanobacteria decreased from 81.31% at 0 h to 19.48% at 48 h. Biochemical methane potential (BMP) tests demonstrated that longer LT-PT durations improved methane yield, with the highest production (1170 NmL CH4) recorded after 72 h of pretreatment. Kinetic modeling using first-order and modified Gompertz equations confirmed that LT-PT enhances methane production efficiency by accelerating substrate hydrolysis. These findings indicate that LT-PT is a promising strategy for optimizing food waste valorization via anaerobic digestion, supporting sustainable waste management and renewable energy generation.