Sunday, April 29, 2007

Substrate specificity of an endo-β-1,4-xylanase with the ability to boost the enzymatic hydrolysis of cellulose in lignocellulosics

Alex Berlin and Jack Saddler. Forest Products Biotechnology, Wood Science, The University of British Columbia, 4609-2424 Main Mall, Vancouver, BC V6T1Z4, Canada

Hemicellulose is together with lignin a major barrier for the effective enzymatic hydrolysis of the cellulose component in lignocellulosics. Recently, we have reported results indicating that there is a strong correlation between the xylanolytic activity of commercial and experimental cellulase preparations and their ability to hydrolyze lignocellulosic glucan. Further studies accomplished by our group demonstrated that a purified endo-β-1,4-xylanase belonging to the family 11 of glycosyl hydrolases, the so-called “true xylanases” family, xylanases lacking cellulase activity, can significantly enhance the ability of a cellulase complex to hydrolyze cellulose in lignocellulosics. The mechanism behind this effect remains unknown. This presentation will describe the results of our study on the substrate specificity of this isolated “boosting” endo-β-1,4-xylanase. The study provides empirical data on the xylanolytic activity of this enzyme on a number of hemicelluloses isolated from softwoods, hardwoods, and agricultural residues.