Effect of shear in a steam explosion reactor on pretreatment and enzymatic hydrolysis yields of dilute-acid pretreated corn stover

Biomass deconstruction remains one of the most critical steps in many biological conversion processes for biomass to fuel and chemical products. The ability to covert lignocellulosic biomass into convertible sugar intermediates at high yields has a direct and strong relationship with economic feasibility of a given process. Dilute acid pretreatment with steam explosion provides both acid hydrolysis required energy and mechanical shearing to disrupt biomass structure chemically and physically. Further, steam explosion been demonstrated in previous work to have a positive impact on whole-process sugar yields, however the impact of varying levels of shear on the dilute-acid pretreatment and enzymatic hydrolysis yields has not been thoroughly characterized. This work seeks to evaluate and quantify the impact of increasing mechanical shear during dilute-acid steam explosion pretreatment across a range of pretreatment temperatures, residence times and acid concentrations through the installation of shearing dies with different geometries and supplementation of steam pressure with high pressure gas to further increase the mechanical shear. The effect of shear will be evaluated through the calculation of cellulose to glucose and xylan to xylose yields during pretreatment, and the pretreated hydrolysate used to conduct high solids (20%) enzymatic hydrolysis experiments to evaluate the impact on cellulose and residual xylan digestibility.