Investigation of Different Pretreatment Methods on Macroalgal Biomass for Efficient Biohydrogen Production via Dark Fermentation

Traditional fossil fuel sources cannot meet increasing energy demand and lead to rising health and global warming concerns. Biohydrogen is a promising alternative to fossil fuels in the zero-carbon economy of the future. The third generation of biofuel that microorganisms produce is biohydrogen. Dark fermentation is gaining attention, which needs little energy and has a higher production rate than other techniques. The biomass of macroalgae has excellent potential as a substrate through dark fermentation. Macroalgae, also known as seaweed, is a highly abundant, fast-growing, and renewable resource that can be sustainably harvested. Macroalgae with significant carbohydrate and no lignin content constitute a promising feedstock for the biohydrogen fermentation process. The complex structure of algae biomass makes hydrolysis difficult, requiring additional time. Pretreatment can improve biofuel production by disrupting molecular bonds and depolymerizing macroalgae. This aids in sugar recovery, reduces chemical loss, and lowers production costs and energy consumption. Pretreatment techniques include physical, chemical, biological, and combined procedures. This review aims to comprehensively analyze various pretreatment methods applied to macroalgae biomass for biohydrogen production by dark fermentation. The review delves into the impact of each method on sugar release and overall biohydrogen yield and covers the strengths and limitations of each approach. In addition, the study investigates cost-effective ecofriendly biohydrogen generation. This review guides future research on optimizing pretreatment methods for maximizing biohydrogen production from different macroalgae biomass, aiming to develop a sustainable and economically efficient process utilizing this promising feedstock.