Materials and Methods
Wet Explosion-Alkaline Pretreatment of Corn Stover for Cellulase Production from T. reesei RUT-C30
Raw corn stover was milled to 1.5 mm and pretreated with wet explosion followed by alkaline extraction at the pilot plant facility of Washington State University. For pretreatment, the chopped corn stover was loaded into a 100 L pretreatment reactor at 25 % (w/w) solid loading, and as the reactor temperature reached 175 °C, an oxygen flow of 6.0 % was added to the steam and sparged into the reactor for 1 min. After a retention time of 25 min, the content of the reactor was collected by flashing out the pretreated biomass into a flash tank. The pretreated biomass (wet exploded) was directly loaded into a steel barrel and was loaded with 1 % w/v NaOH at solid loading of 10 % (w/v). Placement of a steam hose inside of the barrel throughout the whole 5 h of reaction period provided a temperature between 95 and 100 °C. The final pH of the biomass slurry after pretreatment was ~11.0. The pretreated slurry was fractionated into black liquor and pretreated fiber by passing the slurry through a screw press. The resulting pretreated fibers (CF) were then used as an inducer for cellulase production with T. reesei RUT-C30. Compositional analysis of pretreated fiber was conducted according to the NREL/TP-510-42618 procedure.