Optimization of enzyme complexes for lignocellulose hydrolysis

The ability of a commercial Trichodema reesei cellulase preparation (Celluclast 1.5L), to hydrolyze the cellulose and xylan components of pretreated corn stover (PCS) was significantly improved by supplementation with three types of crude commercial enzyme prepartions nominally enriched in xylanase, pectinase, and beta-glucosidase activity. Although the well-documented relief of product inhibition by beta-glucosidase contributed to the observed improvement in cellulase performance, significant benefits could also bo attributed to enzymes components that hydrolyze non-cellulosic polysaccarides. It is suggested that so-called "accessory" enzymes such as xylanase and pectinase stimulate cellulose hydrolysis by removing non-cellulosic polysaccarides that coat cellulose fibers. A high-throughput microassay, in combination with response surface methodolgy, enabled production of an optimally supplemented enzyme mixture. This mixture allowed for a similar to twofold glucose and xylan to xylose hydrolysis targets (99% and 88% conversion, respectively), thereby validating this approach towards enzyme improvement and process cost reduction for lignocellulose hydrolysis.