The synthesis of bio methane through anaerobic digestion using lignocellulosic material as the substrate has a high potential for converting biomass into renewable energy. However, the native lignocellulosic biomass is resistant to microbial hydrolysis due to its recalcitrance, which lowers the efficiency of bioconversion of organic matter into biogas. Therefore, a critical analysis of the relationship between lignocellulose properties and bioconversion effectiveness is required. The process of anaerobic digestion and its rate limiting step, the structural and compositional characteristics of lignocellulosic biomass, recalcitrance and lignocellulose inhibitors, and their major impacts on anaerobic digestion for the production of bio methane are all comprehensively summarised in this review. Additionally, several pre-treatment techniques used on lignocellulosic biomass were thoroughly reviewed in order to contribute to cell wall disintegration and increase bio methane outputs. According to current knowledge, the main drawbacks of these pretreatment procedures are their high energy input and expense needs. In addition to improving the fermentation process, additional research needs to be done on the key structural influences of biomass recalcitrance and the effectiveness of anaerobic digestion, both of which will improve the synthesis of bio methane from lignocellulose.
