Delignification Strategies of Lignocellulosic Biomass: A Crucial Step for Effective Saccharification

The interaction of lignin with hemicellulose hinders cellulose accessibility for the enzyme and limits its performance of bioconversion into chemicals and fuels. Delignification strategy adopted is one of the decisive steps to control, ensuring the viability of the overall bioprocess in biorefinery. The recalcitrant nature of lignin is responsible for the inhibition of enzymatic saccharification. The main phenomena implied in enzyme inhibition are developed. As there is a need for relevant delignification strategies, the present chapter summarizes the major physical, chemical, physicochemical, and biological pretreatment approaches, used in a single or integrated steps to remove lignin and get access to a delignified biomass of quality. The conditions required to ensure high delignification yield as well as the advantages and drawbacks of each pretreatment technique were developed. As the production of lignin inhibitors associated to pretreatment is one of the main barriers affecting the viability of biorefinery, there is a crucial need for application of suitable detoxification strategies to selectively reduce the inhibitory effects of lignin and/or lignin-derived phenolics without a significant loss of fermentable sugars. The various strategies are explored. Finally, as lignin is the only aromatic polymer found in nature which has potential applications in production of biomaterials and chemicals, the development of a sustainable lignocellulosic biorefinery combining the synergetic valorization of polysaccharides and lignin is targeted. Recent developments on this aspect are discussed in this chapter.