5-Sulfosalicylic acid as an acid hydrotrope for the rapid and green fractionation of woody biomass

This study reported that 5-sulfosalicylic acid (5-SSA), a solid acid with hydrotropic properties, could efficiently and rapidly fractionate poplar biomass in an aqueous solution at mild conditions. The experimental results showed that 5-SSA-treatment could deconstruct the biomass recalcitrant intercellular structure and has excellent potential in lignin and hemicellulose dissolution and glucose release through subsequent enzymatic hydrolysis. Under the optimum conditions (80 wt% aqueous 5-SSA solution, 110 degrees C, and 60 min), a lignin removal rate of approximately 69.97%, cellulose recovery yield of more than 80.18% saccharification yield of 76.1% were achieved. 5-SSA acted as a catalyst to depolymerize lignin and hemicellulose by cleaving ether bonds and served as a solvent to dissolve lignin macromolecules by forming 5-SSA clusters and aggregates in water during fractionation. Density functional theory (DFT) indicated that strong H-bonding interactions between 5-SSA and lignin fragments contributed to the breakage of H-bonding network between lignin fragments.

Automated summary

This study demonstrates that 5-sulfosalicylic acid is able to efficiently deconstruct biomass structure and dissolve lignin and hemicellulose, leading to the release of glucose. Under optimized conditions, high lignin removal rate, cellulose recovery yield, and saccharification yield can be achieved.