Development of immobilized cellulase through functionalized gold nano-particles for glucose production by continuous hydrolysis of waste bamboo chopsticks

Cellulase immobilized on silica through the assistance of L-cysteine functionalized gold nano-particle was applied for the continuous hydrolysis of waste bamboo chopsticks powder to produce glucose. The optimal conditions for the continuous hydrolysis were pH 8.0, 50 degrees C. A 4-day reaction with an initial 0.3 g L-1 waste bamboo chopsticks powder, a feed containing 0.2 g L-1 waste bamboo chopsticks powder at a continuous feed and draw rate of 0.5 mL min(-1), and an enzyme loading of 40 mg cellulase (gsilica)(-)1, has 72.0-76.6% conversion rates of repeated hydrolyses that correspond to a total production of 630.5-671.2 mg glucose and are much better than batch hydrolyses. At higher enzyme loading (117 mg cellulase (gsilica)(-1)), higher initial concentration (0.5 g L-1), and higher feed concentration (0.42 g L-1) the conversion rate increases to 82.9% and a total amount of 1418 mgglucose. The immobilized cellulase can be recovered easily by filtration and used repeatedly at least 6 times over a period more than 90 days with a recovered activity approximately the same as or better than previous reactions. Thus the process is promising for scaling up. (C) 2013 Elsevier Inc. All rights reserved.