Measuring Cellulase Accessibility of Dilute-Acid Pretreated Corn Stover

To enable a new biorefinery industry, lignocellulosic biomass must be cost effectively hydrolyzed to fermentable sugars. To maximize the fermentable sugar stream from corn stover, a dilute acid pretreatment step has been used traditionally to facilitate enzyme access to the cellulose fraction. A key factor for successful enzymatic digestion of lignocellulosic biomass is providing cellulase enzymes access to the β-(1→4) glycosidic bonds of microcrystalline cellulose. The extent of xylan removal from corn stover by dilute-acid pretreatment increased with higher severities, with minimal change in the amount of lignin. The cellulase-cellulose interactions were enhanced by this pretreatment. Higher extents of xylan removal resulted in greater cellulase adsorption and higher overall cellulose conversions. Trichoderma reesei Cel7A had a low affinity to lignin, thus biomass recalcitrance in this case was most likely not due to loss of this cellulase via adsorption to lignin. This is an abstract of a paper presented ACS Fuel Chemistry Meeting (Washington, DC Fall 2005).