Feasibility of boosting single-step biohydrogen production from sugarcane bagasse mediated by RSBA-biochar

This research offers a novel approach by utilizing the solid residue of biomass left after fermentation and examining the effects of producing biochar from this residue. Specifically, it investigates biochar derived from the solid residue of sugarcane bagasse, with biochar initially added before fermentation (RSBA-biochar), to boost single-step biohydrogen production through dark fermentation of sugarcane bagasse. RSBA-biochar II (RSBA II), added before fermentation, significantly boosted H₂ yield, reaching 2706.05 mL/L (180.18 mL/g) at 7 g/L, with an increase of 2.82 times compared to the biochar group and 3.21 times compared to the control without biochar. The H₂ production rate was 126.88 mL H₂/L/h with a 7.27-h lag time, and the substrate utilization yield of 52.65% was tripled compared to the control. Overall, the unique physicochemical properties of RSBA II demonstrated improved pH buffering capacity due to its initial high pH and alkalinity, enhanced the NADH-dependent H₂ production pathway with a higher NADH/NAD⁺ ratio of 0.76, and increased electron conduction efficiency during the fermentation process. This research provides an in-depth insight into the role of RSBA-biochar supplementation in improving the efficiency of single-step biohydrogen production from sugarcane bagasse, promising to facilitate the efficient utilization of inexpensive biomass for low-cost bioenergy production, contributing to the development of waste valorization and the circular bioeconomy.