Pretreatment and anaerobic co-digestion of lignocellulosic biomass: Recent developments

This review examines recent developments in pretreatment and anaerobic co-digestion of lignocellulosic biomass (LCB) for enhanced biogas production. Despite being the most abundant organic material with significant potential for renewable energy generation, LCB's complex structure of lignin, cellulose, and hemicellulose presents challenges for effective biodegradation. The review explores various pretreatment methods - physical (milling, microwave, extrusion), chemical (alkaline, acid, deep eutectic solvents), biological (fungi, enzymes), and physicochemical approaches that enhance LCB digestibility by breaking down its recalcitrant structure. Additionally, it examines the anaerobic co-digestion of LCB with nutrient-rich substrates like manure, food waste, algae, and wastewater sludge to optimize the carbon-to‑nitrogen ratio and improve methane yields. The paper highlights how combining different pretreatment techniques and employing co-digestion approaches enhances biogas production efficiency. This comprehensive analysis provides valuable insights into developing more effective and sustainable methods for converting LCB into biogas, supporting the transition from fossil fuels to renewable energy sources.