Unveiling the potentials of biohydrogen as an alternative energy source: Strategies, challenges and future perspectives

Bio-hydrogen emerges as an environmentally friendly energy carrier, promising to diminish our reliance on fossil fuels. Employing biological approaches for hydrogen production aids in the dual objectives of waste management and energy generation. The economic viability of producing renewable bio-hydrogen from waste biomass is considerable, though the realization of extensive industrial-scale production remains an ongoing aspiration. This review underscores present viewpoints on the generation of bio-hydrogen as an alternative energy reservoir. The facilitation of bio-hydrogen production encompasses techniques like photolysis, fermentation, and electrochemical processes. To augment bio-hydrogen production, optimizing various influential production factors is imperative. Employing bioreactors with tailored designs and configurations can significantly enhance productivity. The incorporation of hybrid and novel strategies to bolster bio-hydrogen production, is recognized as a sturdy strategy. This comprehensive review highlights that biological methods, particularly photo and dark fermentation using various microorganisms, are the most prominent and promising techniques for sustainable bio-hydrogen production. While advancements in bioreactor design, genetic engineering, and the application of nano-materials (especially Ni and Fe) have improved yields, large-scale implementation remains hindered by economic and technological challenges, requiring further research and policy support. • Biohydrogen production methods are described thoroughly. • Bioreactors and other factors influence on biohydrogen are also elucidated. • Nano-materials and nanotechnology devices for biohydrogen production are also discussed. • Ni and Fe are most promising nanomaterials for H 2 production. • Constraints and future challenges are presented based on identified literature gaps.