Enhancing Lignin Depolymerization and Enzymatic Hydrolysis of Lignocellulose by the Synergy of Ball Milling and Fenton-like Reactions

Pretreatment is critical to promote enzymatic hydrolysis for the production of lignocellulose-based biofuels. In this study, inspired by the lignin degradation through the mouthpart and symbiotic fungi of termite, a synergistic biomass pretreatment system using ball milling and Fenton-like reactions was first proposed. Ball milling can reduce the particle size, while Fenton-like reactions can modify the lignin and cause pore structures, leading to a 44.2% increment in total pore volume. In addition, lignin-based aromatic aldehydes can be produced with a 67.1% increase in yield over no-ball milling conditions, which can be used as natural mediators. More importantly, under the optimal pretreatment conditions (1.5% H2O2, 1 mg L–1 Fe-TAML catalyst, 300 rpm, and 12 h), the highest initial glucose productivity was 2.83 g L–1 h–1, which is 2.4 times higher than untreated samples. The conversion of cellulose in 24 h is enhanced by 62.3% with half of the enzyme input when compared with untreated wheat straw. Thus, the synergy of ball milling and Fenton-like reactions helps to promote lignin depolymerization and enzymatic hydrolysis of lignocellulose.