Enhancing Lignin Depolymerization and Enzymatic Hydrolysis of Lignocellulose by the Synergy of Ball Milling and Fenton-like Reactions
Kai Lin, Ao Xia, Yu Yang, Yun Huang, Xianqing Zhu, Xun Zhu, Kaiyong Cai, Zidong Wei, Qiang Liao
Abstract
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% H 2 O 2, 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.