A Comprehensive Review on Enhanced Biohydrogen Production: Pretreatment, Applied Strategies, Techno-Economic Assessment, and Future Perspective

In the direction of sustainable and zero carbon energy production, hydrogen is considered as a potential fuel with high heating value and energy content compared to other fossil fuels. The present review focuses on conventional and advanced biohydrogen production by utilizing low-cost biomass feedstock through dark fermentation, photo fermentation, bio-photolysis, microbial electrochemical cell, as well as integrated and co-fermentation approaches. Different substrate pretreatment methods, such as thermo-aero-size reduction, acid–alkali or biocatalyst, and combined pretreatment methods are investigated, which can potentially enhance hydrogen productivity multiple-fold. This review explores the application of various hydrogen-selective polymeric membranes, which improves biohydrogen production yield and reduces purification costs. Techno-economic assessment of different biohydrogen production technologies is reviewed based on technological advancements for improved production yield and energy efficiency as well as economic performance enhancement depending upon a minimum selling price, capital cost, operating cost, and profitability. Furthermore, an extensive investigation of the continent or country-specific biohydrogen production challenges is presented. These findings of the current study will explore novel biohydrogen production processes with an aspect of energy efficiency, economics, and environmental footprint.