Synergistic Valorization: Generating Bioelectricity and High- Protein Animal Feed From Fermented Crop Residues

Background The microbial communities present in agricultural wastes and their potential for bioelectricity generation through microbial metabolism warrant exploration for potential synergistic biotechnological applications. Methods Utilizing a combination of culture, biochemical assays, and 16S rRNA sequencing, known and novel microorganisms within maize husk, sweet potato peel, wheat shaft, and sugar cane shaft substrates were identified. The proximate, mineral, and vitamin content of the agro-wastes were determined before and after fermentation to ascertain the agro-waste substrate suitability for animal feed. A dual-chamber microbial fuel cell (MFC) was constructed to evaluate the bioelectricity generation potential of these substrates over 21 days. Results Potato peel exhibited the highest bacterial count at 3.8×10 ⁴ CFU/ml, while maize husk had the highest fungal load at 6.55×104 SFU/ml. Fermentation significantly enhanced the protein, mineral, and vitamin content of the agrowastes while reducing fiber and carbohydrate levels. Notably, maize husk produced the highest voltage of 68 mV and current of 77 µA compared to other substrates. The mixed culture of L. fusiformis and B. subtilis also demonstrated substantial voltage and current outputs from maize substrate during days 1–6. Pichia kudriavzevii MN007220.1, Geotrichum candidum MK943778.1, Bacillus subtilis NR102783.2, and Lysinibacillus fusiformis KP419973.1 were confirmed in these agro-waste substrates. Conclusions These findings underscore the dual potential of agricultural wastes as a valuable source for bioelectricity generation and as a nutritious supplement for animal feed post-fermentation, aiding digestibility. This emphasizes their importance in sustainable agricultural practices and biotechnological applications.