Mechanism of Biochar for Enhancing Volatile Fatty Acids Production during Anaerobic Fermentation of Food Waste
This study investigated the effects of biochar on volatile fatty acids (VFAs) production, biogas composition, physicochemical properties of the fermentation broth, and microbial community structure through batch anaerobic fermentation experiments using food waste as the substrate. The results demonstrated that the addition of biochar (1 g/L) significantly enhanced VFAs production, with the total VFAs concentration reaching 2150 mg/L in the biochar group, which was 30.2% higher than that of the control group (1651 mg/L). Acetic acid, propionic acid, and butyric acid were identified as the primary VFAs components. In the fermentation system, biochar exhibited a notable pH-buffering effect, stabilizing the fermentation environment. Additionally, its porous structure adsorbed ions during the fermentation process, resulting in a slightly lower electrical conductivity compared to the control group. Microbial community analysis revealed that biochar addition enriched key acidogenic bacteria, such as Defluviitoga and norank_f__Family_XI, optimizing the microbial community structure, and thereby facilitating organic acid production. In summary, biochar effectively promoted the efficient accumulation of VFAs during anaerobic fermentation of food waste by improving the fermentation microenvironment, enhancing system buffering capacity, and regulating microbial community composition. These findings provide theoretical support for sustainable enhancement of resource utilization of food waste.