Tandem Mechano-Enzymatic Catalysis: A Green Revolution in Lignocellulosic Biomass Pretreatment via Contact-Electro-Catalysis
Linyang Li, Junjun Wu, Ao Xia, Xun Zhu, Qiang Liao
Abstract
The recalcitrance of lignocellulosic biomass poses a critical bottleneck in sustainable biorefining, where conventional pretreatments rely on energy-intensive, chemically hazardous, or thermally extreme processes. Here, we introduce a tandem mechano-enzymatic strategy using contact electrocatalysis (CEC), a newly emerging mechanocatalysis method, to enable green, efficient, and scalable biomass deconstruction followed by enzymatic hydrolysis. By synergizing ultrasound-driven mechanical disruption with recyclable SiO 2 microparticle catalysts, the CEC method achieves over 80% degradation of raw wheat straw within 4 h under ambient conditions─without high temperatures, toxic solvents, or irreversible catalysts. Such degradation is enabled by the reaction with free radicals generated by SiO 2 microparticle catalysts, which maintain good performance even after five cycles. High-level quantum chemistry calculations were also adopted to explore possible reaction pathways. Compared to the conventional ultrasound pretreatment, the CEC pretreatment significantly enhances cellulose and hemicellulose conversion efficiencies by 35.8% and 78.1%, respectively, while reducing cellulose crystallinity by 12% (CrI = 32.44 vs 36.94 for raw biomass). This structural modification facilitates subsequent enzymatic hydrolysis, yielding glucose concentrations comparable to energy-intensive ball milling. More importantly, the tandem strategy eliminates secondary waste generation and leverages reusable catalysts, aligning with the circular economy. Our work establishes CEC as a transformative pretreatment paradigm, bridging the gap between industrial scalability and sustainable biomass valorization for biofuels and bioproducts.