Strategic Design Principles for Greener Biorefinery: A Substrate-Process Matrix Emphasizing Complete Lignocellulose Utilization over Variant Biomass

Abstract

Lignocellulosic biomass (LCB) presents a promising feedstock for sustainable biofuel and bioproduct production. Despite its abundance, only a fraction of LCB is currently utilized, highlighting its complex compositions and the need for advanced biorefinery technologies. This study investigates two biorefinery processes, 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 biomasses based on their lignin structures and physiochemical properties, which influence their reactivity and suitability for specific treatments. We evaluate pretreatment methods such as organosolv and deep eutectic solvents, which demonstrate efficacy in lignin removal. Through analyses on mass balance, 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 yield and exhibits higher economic feasibility, PT-CTH is more sustainable and utilizes the whole biomass more efficiently due to its efficient pretreatment. Hardwood, softwood, and grass demonstrate high resource efficiency with hardwood producing the highest yield of monomers in RCF. Seed coats, rich in C-lignin, offer high potential for aromatic monomer production, but demonstrate low resource efficiency while barks require tailored approaches due to their complex lignin units. This study proposes recommendations to advance efficient, sustainable biorefinery operations, leading the structural diversity within LCBs for optimized biomass utilization, and supports the development of more economic and environmentally friendly biorefinery techniques.