(406f) Effect of Biomass Size Partitioning On Pretreatment and Enzyme Requirements Using Response Surface Analysis

Pretreatment and enzyme hydrolysis are critical steps enabling conversion of biomass to ethanol. They promote separation of hemicellulose and lignin from cellulose and conversion of oligosaccharides to monosaccharides. Partitioning of biomass based on anatomical differences is well accepted as affecting composition and digestibility. Fractions vary in their resistance to milling resulting in various size fractions upon sieving. Milling and sieving could offer simpler partitioning that could be exploited to facilitate pretreatment and more efficient use enzymes for digestion. This would reduce the usage of chemicals, energy and enzymes expended during the production of ethanol. In this work, pre-milled biomass (about 1 inch screen size) was partitioned using 2mm and 1 mm screen sizes, and response surface analysis was performed to evaluate the effect of biomass size partitioning on pretreatment severity and enzyme loading requirements. Pretreatment was conducted, using water at high temperature, as a model pretreatment. Pretreatment time and enzyme loading were the factors investigated using rotatable central composite design for enzymatic digestibility and fermentation of various size fractions of switchgrass.