Pretreatment of biomass for the removal of lignin is an appropriate approach for the maximum
usage of digestible contents present in it for its conversion to biogas. Various methods have been
used for delignification and proved to be good in terms of biogas production. Maximum lignin
was removed by acidic delignification process leading to the production of 76% methane.
Alkaline delignification followed by digestion could result in the production of 71% methane
whereas thermal treatment resulted in 73% methane.