Cellulose lignin removal

Yang, B., and Wyman, C. E., 2000, Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of com stover cellulose, Biotechnol. Bioeng. 86 88-95. 

In ARP pretreatment of hybrid poplar, deUgnification is increased with the treatment severity, but xylan removal occurs only to a certain extent. Increase of temperature from 175 to 195 °C in ARP does not affect xylan/lignin removal in hybrid poplar, yet the glucan digestibility of treated solid is increased. This is caused by an increase of cellulase accessibility to cellulose created by breakage of certain bonds and reconfiguration of the components in hemicellulose-lignin matrix. Crystallinity index of hybrid poplar increases after the ARP treatment. It is primarily caused by the removal of amorphous components,... 

The removal of lignin not only increases cellulose accessibility but also enhances cellulase availability. Lignin and its complexes physically and chemically resist enzymatic attack, and condensed lignin also has the ability to adsorb protein from aqueous solutions (50). Thus, it appears that lignin removal not only opens up more space for enzymes but also reduces non-specific enzyme adsorption, improving the efficacy of hydrolysis (41, 51,52,53,54). 

Figure 6. Effect ofxylan removal (a) and lignin removal (b) on enzymatic digestibility of cellulose produced by hemicellulose hydrolysis of com stover at the conditions noted.

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