Resourceful utilization of Bougainvillea horticultural waste for synchronous degradation and power generation in MFCs

The disposal of horticultural waste derived from Bougainvillea species poses substantial environmental challenges in coastal cities of southeastern China. This study innovatively employs Bougainvillea horticultural waste (BHW) as the main substrate in microbial fuel cells (MFCs) for simultaneous organic degradation and bioenergy recovery, with an acid-pretreated BHW-fed MFC (MFC-ABG) included for comparison. Results indicated that the untreated BHW-fed MFC (MFC-BG) achieved a peak voltage of 0.401 V and sustained operation for 19 days, coupled with 78.7% polysaccharide removal. Metagenomics showed that MFC-BG significantly enriched electroactive Geobacter (29.39%) and hydrolytic Proteiniphilum (2.69%), driving lignocellulose decomposition through oxidative auxiliary enzymes (AA4/AA6). Comparatively, MFC-ABG achieved an enhanced voltage of 0.706 V and a high polysaccharide reduction efficiency of 85.6%, benefits attributable to acid-induced substrate solubilization and glycoside hydrolase (GH)-dominated enzymatic shifts. Although microbial community diversity declined in both MFC systems, MFC-BG retained a higher species richness (MFC-BG: Sobs = 28,209; MFC-ABG: Sobs = 25,746), reflecting the adaptive resilience of the associated microbial community. This study confirms BHW as a viable feedstock for MFCs and clarifies the microbial mechanisms underlying the synergistic coupling of substrate degradation and electron transfer.