The effects of biomimetic carrier and nano-sized Fe2O3 on biogas production from food waste: performance and mechanisms

To enhance biogas production from food waste (FW) via anaerobic digestion (AD), batch experiments were conducted at 36.5 ± 0.5°C using Fe 2 O 3 nanoparticles (Fe 2 O 3 NPs), 3D-printed reticulated rumen biomimetic carrier (BC), and Fe 2 O 3 NPs loaded on BC (Fe 2 O 3 NPs@BC). Results demonstrated that all additives significantly enhanced AD performance, along with the Fe 2 O 3 NPs achieved the highest cumulative methane yield of 378.7 mL/g VS, representing a 24.8% increase relative to the Control group. The additives may act as electron shuttles via Fe 3+ /Fe 2+ cycling and appear to enhance electron transport system activity and system stability. Microbial analysis showed the additives increased methanogenic archaeal diversity. The dominant bacterial phyla were Firmicutes (31%∼38%) and Bacteroidota (31%∼51%), and Fe 2 O 3 NPs increased Bacteroidota by 65.0% compared with the Control. Methanobacterium and Methanosaeta dominated methanogens and drove hydrogenotrophic and acetoclastic methanogenesis. This study reveals mechanistic insights into nanomaterial-biocarrier interactions in food waste energy conversion.