Utilization of algal biomass for biohydrogen production and Storage: Mechanistic innovations and sustainable engineering strategies

Hydrogen (H₂) has emerged as an essential energy carrier in the transition to low-carbon and sustainable energy systems. However, traditional H₂ manufacturing is significantly reliant on fossil fuels, raising concerns over carbon emissions and enduring sustainability. This research examines the viability of algal biomass as a sustainable and eco-friendly feedstock for biological H₂ (bio-H₂) production. Critical pathways, such as direct and indirect biophotolysis, dark fermentation, and photofermentation, are meticulously examined, focusing on their biochemical mechanisms, yields, and scalability. This study emphasizes production while addressing a critical research gap by examining suitable hydrogen storage technologies, specifically metal hydrides, cryogenic storage, chemical carriers, and sophisticated carbon-based nanostructures that can be connected with algal H₂ systems. A unique framework is proposed that links biological production with storage solutions to optimize energy efficiency, safety, and economic feasibility. Significant attention is placed on engineering advances, ecological benefits, and industrial significance in both decentralized and large-scale systems. The evaluation concludes by identifying significant technological barriers and proposing future research directions to bridge the gap between laboratory-scale feasibility and industrial-scale implementation. This study offers a comprehensive and forward-thinking perspective on establishing a sustainable H₂ economy with algal biomass.