title: Characterization of Rice Straw Prehydrolyzates and Their Effect on the Hydrolysis of Model Substrates Using a Commercialendo-Cellulase, β-Glucosidase and Cellulase Cocktail.
abstract: Pretreatment and enzymatic saccharification are two major upstream processes that affect the economic feasibility and sustainability of lignocellulosic biofuel production. Cellulase-inhibiting degradation products, generated during dilute acid pretreatment, increase enzyme usage, and therefore, it is essential to mitigate their production. In an attempt to elucidate the most deleterious degradation product to enzymatic hydrolysis, hydrolyzates were generated from rice straw, and their effect on enzyme activity was determined. Ground rice straw was subjected to the following pretreatments having a combined severity factor of 1.75: T1-160 °C, pH 1.7; T2-180 °C, pH 2.25; and T3-220 °C, pH 7.0. The liquid prehydrolyzates were freeze-dried, and their inhibitory effects on the activities of a commercial cellulase cocktail,endo-cellulase, and β-glucosidase were determined using filter paper, carboxymethyl cellulose, and cellobiose, respectively. Addition of 15 g L-1of T1, T2, or T3 freeze-dried prehydrolyzates resulted in 67%, 57%, and 77% reduction in CMC-ase activity ofendo-cellulase, respectively. In the presence of 35 g L-1of T1, T2, or T3 prehydrolyzates, the filter paper activity of the cellulase cocktail was reduced by 64%, 68%, and 82%, respectively. Characterization of the freeze-dried prehydrolyzates showed that T3 had significantly higher xylo-oligosaccharides and total phenolic content than T2 and T1.
authors.affiliation: Department of Food Science, University of Arkansas , 2650 N. Young Ave, Fayetteville, Arkansas 72704, United States.
authors.forename: Kalavathy
authors.initials: K
authors.lastname: Rajan
authors.affiliation: Department of Biological and Agricultural Engineering, University of Arkansas , 203 Engineering Hall, Fayetteville, Arkansas 72701, United States.
authors.forename: Danielle Julie
authors.initials: DJ
authors.lastname: Carrier
keywords: Cellobiase activity; Enzyme inhibition; Filter paper activity; Phenolics; Prehydrolyzate; Rice straw; Xylo-oligosaccharides; endo-Cellulase; β-Glucosidase