Low molecular weight thermostable β-D-glucosidase from Acidothermus cellulolyticus

Industrial use of cellulase enzymes, including beta -D-glucosidases, can be greatly improved and expanded by the discovery and characterization of more robust, thermotolerant enzymes. A new thermostable beta -D-glucosidase was isolated from Acidothermus cellulolyticus culture broth. This enzyme has a molecular weight of 52.5 kDa, an isoelectric pI of 4.1, and a pH activity optimum of 4.5. The optimum temperature for activity on p-nitrophenyl- beta -D-glucoside is 63 degree C. This value is approximately 20 degree C higher than temperature optima displayed by most previously characterized beta -D-glucosidases.