A comprehensive pre-treatment strategy evaluation of ligno-hemicellulosic biomass to enhance biogas potential in the anaerobic digestion process

Effective pretreatment of ligno-hemicellulosic biomass has emerged as a pre-requisite for its efficient conversion into biogas through the anaerobic digestion (AD) process. Assessment of various pre-treatment methods shows microbial pretreatment to be the most promising, economically viable, and environment-friendly option. Microbial pretreatment offers the advantages of low energy consumption and minimal pollution generation, thus making it a promising avenue for enhancing biogas yields from biomass. Fungi and bacteria, along with their enzymes, play pivotal roles in this method. Fungal pretreatment, involving cellulose and lignin-degrading species like brown-rot and white-rot fungi, have shown improved biogas yield. Bacterial and enzymatic pretreatments offer quicker results, making them attractive options for shortening the reaction time. Microbial consortia have shown remarkable efficiency in biomass degradation and its anaerobic digestion under thermophilic conditions. Physical pretreatment methods, such as mechanical size reduction, have shown potential to increase biomass accessibility and enhance biogas production. However, due to its energy-intensive nature and for improving biogas yields, further research is needed to develop more cost-effective approaches. The combination of physical and biological pretreatment methods offers a promising approach to effectively pretreat ligno-hemicellulosic biomass for improved biogas production.