Continuous cellobiose hydrolysis using self-immobilized β-glucosidase fromAspergillus phoenicis QM 329 in a fluidized-bed reactor

Abstract

Aspergillus phoenicis QM 329 was grown in the shape of beads in shake flasks and in an air-lift fermentor. The production of β-glucosidase started when the carbon source, glucose, was consumed. The β-glucosidase activity was retained in the beads at a pH below 6.0. The influence of bead diameter on enzyme activity and the pH and temperature optima for cellobiose hydrolysis has been studied. The enzyme-containing beads were used in a fluidized-bed reactor for continuous cellobiose hydrolysis, and a productivity of 2.0 g/L-h at a substrate conversion of 76% was obtained. The self-immobilized β- glucosidase is a stable and reusable enzyme with a half-life of 700 h when operating at 50°C and pH 4.8.