Therefore, an ideal pretreatment is needed to reduce the lignin
content and crystallinity of cellulose, and increase the surface area
of these materials (Wang et al., 1998). Removal of lignin from biomass
before biological processing improves cellulose digestibility,
reduces downstream agitation power requirements, provides less
sites for nonproductive cellulase adsorption, reduces dissolved lignin
compounds that are toxic to fermentations, facilitates cell and
enzyme recovery and recycling, and simplifies the distillation steps
(Wyman et al., 2004).