Effect of oxygen delignification on the rate and extent of enzymatic hydrolysis of lignocellulosic material

In this study, we examined the effect of oxygen delignification on the rate and extent of enzymatic hydrolysis (using commercial cellulase and P-gluco sidase) of a number of lignocellulosic substrates, including kraft pulp (mo del substrate), pulp mill primary clarifier sludge (PCS) and steam-exploded Douglas fir chips. Oxygen delignification removed up to 67% of the lignin from softwood pulp and improved the rate of, and yield from, hydrolysis by up to 111% and 174%, respectively. Glucose yield varied linearly with fract ional lignin removal. Oxygen delignification of primary clarifier sludge im proved hydrolysis yield by up to 90%. However steam-exploded Douglas fir wa s very resistant to hydrolysis at low enzyme loading, and oxygen delignific ation decreased hydrolysis rate and yield. (C) 2001 Elsevier Science Ltd. A ll rights reserved.