CARBOXYMETHYLCELLULASE AND AVICELASE ACTIVITIES FROM A CELLULOLYTIC CLOSTRIDIUM STRAIN A11

The extracellular cellulase enzyme system of Clostridium All was fract ionated by affinity chromatography on Avicel: 80% of the initial carbo xymethylcellulase (CMCase) activity was adhered. This cellulase system was a multicomponent aggregate. Several CMCase activities were detect ed, but the major protein P1 had no detectable activity. Adhered and u nadhered cellulases showed CMCase activity with the highest specific a ctivity in Avicel-adhered fraction. However, only adhered fractions co uld degrade Avicel. Thus, efficiency of the enzymatic hydrolysis of Av icel was related to the cellulase-adhesion capacity. Carboxymethylcell ulase and Avicelase activities were studied with the extracellular enz yme system and cloned cellulases. Genomic libraries from Clostridium A ll were constructed with DNA from this Clostridium, and a new gene cel 1 was isolated. The gene(s) product(s) from cell exhibited CMCase and p-nitrophenylcellobiosidase (pNPCbase) activities. This cloned cellula se adhered to cellulose. Synergism between ''adhered enzyme system'' a nd cloned endoglucanases was observed on Avicel degradation. Conversel y, no synergism was observed on CMC hydrolysis. Addition of cloned end oglucanase to cellulase complex led to increase of the V-max without s ignificant K-m variation. Cloned endoglucanases can be added to cellul ase complexes to efficiently hydrolyze cellulose.