“…Catalyst development play an important role in achieving this goal. Over the last a few decades, different types of catalysts (e.g., metal nanoparticles, enzyme, acidic or basic candidates) have been frequently designed and investigated ( Alonso et al, 2013 ; Nanda et al, 2016 ; Hu et al, 2019 ; Liu et al, 2021 ). This special issue concentrates on the pretreatment of biomass using enzymes, anaerobic digestion of naive source, various factors on the thermal pyrolysis, value-added chemicals synthesis and degradation.…”