Enzymatic Hydrolysis of Corn Stover Pretreated in High Shear Bioreactor

Abstract

Bio-fuel became worldwide focus due to dwindling of fossil fuels and its environmental impact. Pretreatment, saccharification, fermentation, and purification are the important steps involved in the production of bio-fuel from the biomass. As pretreatment is the prime and most expensive step in a conversion process, many investigations are currently involved in developing a viable pretreatment method(s). In addition, pretreatment has pervasive impacts on all other major unit operations in overall conversion process from choice of feedstock through to size reduction, hydrolysis, fermentation, separation, residue process. There are several pretreatment methods using physical, chemical and biological principles which are under various stage of investigation. Extrusion is a process where ingredients are subjected to heating, mixing, shearing, resulting in physical and chemical changes during the passage through the extruder, it can be used as one of the physical pretreatment methods towards biofuel production. The objective of this study was to evaluate the effect of high shear parameters on carbohydrate release from corn stover. Corn stover was pretreated in high shear bioreactor with five screw speeds (25, 50, 75, 100, and 125 rpm) and five barrel temperatures (25, 50, 75, 100, and 125 C). Multi-enzyme complex and -.glucosidase were used in enzymatic conversion of pretreated corn stover and glucose, xylose, galactose, arabinose and mannose was measured using HPLC. Screw speed and temperature had significant effect on carbohydrate release from corn stover. Higher glucose and combined sugar conversion of about 31 and 52% recorded at 125 rpm and 125C and it was 1.5 and 1.6 times more than control. High shear pretreatment resulted in 85 and 80% of potential glucose and combined sugar from corn stover.