Continuous pH Monitoring During Pretreatment of Yellow Poplar Wood Sawdust by Pressure Cooking in Water

Yellow poplar wood sawdust consists of 41% cellulose and 19% hemicellulose. The goal of pressure cooking this material in water is ty hydrate the more chemically resistive regions of cellulose in order to enhance enzymatic conversion to glucose. pretreatment can generate organic acids through acid-catalyzed degradation of monosaccharides formed because of acids released from the biomass materialor the inherent acidity of the water at temperatures above 60 deg C. The resulting acids will further promote the acid-catalyzed degradation of monomers that cause both a reduction in the yield and the formation of fermentation inhibitors such as hydroxymenthyl furfural and furfural. A continuous pH-monitoring system was developed to help characterize the trends in pH during pretreatment and toassist in the development of a base (2.O M KOH) addition profile to help keep the pH within a specified range in order to reduce any catalytic degradation and the formation of any monosaccharide degradation products during pretreatment. The results of this work are discussed.