Junyeong Park, Orlando J. Rojas, and Sunkyu Park. Department of Forest Biomaterials, North Carolina State University, Campus Box 8005, Raleigh, NC 27695
Lignin is an important recalcitrant factor in enzymatic hydrolysis. Several studies have shown that the inhibition by lignin in enzymatic hydrolysis processes is mainly due to their non-specific adsorption onto lignin and also the physical blocking of binding sites. However, the inhibition mechanism is not clearly identified. In this study, lignin samples were isolated from differently pretreated wood biomass by extensive hydrolysis with cellulolytic enzymes. The adsorption behaviors of cellulases onto the isolated lignin samples were investigated. Lignins isolated from the thermochemical pretreatment at different conditions were tested. The effect of oxidation by oxygen bleaching process on enzyme-lignin adsorption was also examined. Preliminary experiments showed that there were differences in the initial adsorption rate for the isolated lignin samples. The oxygen bleaching process also induced changes in initial adsorption rate and maximum adsorption capacity of the lignins. Based on these results, enzyme kinetics for each isolated lignin was studied. Finally, structural differences between the samples were analyzed and factored in correlations relevant to characteristic adsorptive behaviors.
