Effect of lignins from different lignocellulosic materials on adsorption of enzyme components

Non-productive cellulase adsorption onto lignin has been always deemed as having a negative impact during enzymatic hydrolysis of lignocellulosic feedstocks. Therefore, understanding of enzyme–lignin interactions is essential for the development of enzyme mixtures and genetically modified of plant and enzyme. Mill Wood Lignin(WML) from six different lignocellulosic biomass (aspen, pine, corn stover, kenaf and two Arabidopsis lines: wild-type and SALK mutant of fah1) were prepared to investigate the effect of the lignin characteristics on adsorption of enzyme components. It was found that lignin sources affected enzyme adsorption by structural features like functional groups and lignin composition. Guaiacyl (G) lignin had higher adsorption capacity on enzyme than syringyl (S) lignin. The low S/G ratio and high uniform lignin fragment size had good correlation with the high adsorption capacity. The higher content of phenolic hydroxyl groups, lower content of carboxylic acid groups resulted in the stronger adsorption affinity for corn stover lignin than kenaf lignin and aspen lignin. The lower aliphatic hydroxyl, by reducing hydrophobic interactions, could explain for the higher adsorption capacity of pine lignin than corn stover lignin. The behavior of mono-component enzyme resulted in adsorption was also studied and found that cellobiohydrolase (CBH) and xylanase were most adsorbed by all lignins, endoglucanase (EG) showed less inhibition, and β-glucosidase (BG) was least affected by lignins, indicating the important role of carbohydrate binding module (CBM) in protein adsorption.