Strategic design principles for greener biorefineries: a substrate–process matrix emphasizing complete lignocellulose utilization from various biomass feedstocks

Abstract

Lignocellulosic biomass are promising feedstocks for sustainable biofuel and bioproduct production. Despite their abundance, however, only a fraction of biomass is utilized, highlighting their complex compositions and the need for advanced biorefinery technologies. This study investigates two biorefinery strategies, i.e., pretreatment followed by catalytic transfer hydrogenolysis (PT-CTH) and reductive catalytic fractionation (RCF), aiming to harvest high-value lignin monomers from diverse biomass feedstocks including hardwood, softwood, grasses, barks, and seed coats. We classify these biomass feedstocks based on their lignin structures and physiochemical properties, which influence their reactivity and suitability for specific treatment processes. Through analyses on mass balance, environmental sustainability, and economic profitability, we propose recommendations and suggest future research directions to improve current processes for each biomass species. Our analysis reveals that while RCF converts lignin to higher monomer yields and exhibits higher economic feasibility, PT-CTH is more sustainable and utilizes the whole biomass more efficiently due to its efficient pretreatment. Hardwood and grass demonstrate high resource efficiency, with higher yields of monomers in RCF; softwood and barks are preferred feedstocks for PT due to higher extractive contents and carbohydrates compositions. Seed coats, rich in C-lignin, offer high potential for aromatic monomer production, but demonstrate lower resource efficiency while barks require tailored approaches due to their complex lignin units. This study proposes recommendations to advance efficient, sustainable biorefinery operations, exploiting the structural diversity of different biomass for optimized biomass utilization, and supports the development of more economical and environmentally friendly biorefinery techniques toward carbon neutrality.