Sustainable Pretreatment of Lignocellulosic Biomass for Biohydrogen Production

Biological hydrogen production from lignocellulosic residues is increasingly recognized as a promising route toward sustainable fuel production. However, efficient conversion of these materials requires appropriate pretreatment strategies to enhance carbohydrate accessibility while preserving the quality of the resulting hydrolysates for fermentation to hydrogen. To date, most pretreatment studies have primarily emphasized maximizing sugar release and biomass fractionation, often overlooking the critical role of hydrolysate quality and hydrogen fermentability. This review evaluates lignocellulosic biomass pretreatment technologies with a specific focus on their impacts on hydrogen fermentability. Among all of the well-studied pretreatments, only a few are good candidates for biohydrogen production from lignocellulosic biomass. In particular, the selection of an optimal pretreatment approach was shown to depend not only on the physicochemical characteristics of the biomass but also upon the metabolic capabilities and substrate utilization patterns of the microorganisms employed. This article highlights the need for integrated optimization of pretreatment and fermentation processes and identifies key challenges and opportunities for advancing lignocellulosic biohydrogen production.