Pretreatment methods for enhanced biomethane production from crop residues: Progress, challenges, and future perspectives

Abstract

The increase in the global population has caused a rise in the agricultural practice, consequent to increased generation of Crop residues (CR). CR are readily available and less expensive renewable lignocellulosic resource, which is getting more attention in the sector of renewable energy and sustainable development. Pretreatment is an important step in transforming CR into high value chemicals through suitable process. To break down the lignocellulosic CR’s resistance and enhance its disintegration into lignin, cellulose, and hemicellulose, a range of pretreatment techniques are used. This review explores the use of advanced pretreatment technologies for CR aimed at improving biomethane production. Discusses the characteristics of CRs, evaluates different pretreatment approaches—physical, chemical, biological, and hybrid methods—and assesses strategies and potential new approaches for integrating waste and energy production. Lignocellulosic wastes, primarily CR stands out the most efficient biomass source for biomethane production because of their abundant availability, high carbon/nitrogen ratio and low ash content. In case of pretreatment methods, hybrid/combined pretreatment emerges as the most promising option when compared to single pretreatment methods, because it offers effectiveness and flexibility in enhancing the biomethane production.