ADSORPTION CHARACTERISTICS OF CELLULOLYTIC ENZYMES FROM THE ANAEROBICFUNGUS PIROMYCES SP STRAIN E2 ON MICROCRYSTALLINE CELLULOSE

Characteristics of the cellulolytic system of the anaerobic fungus Pir omyces sp, strain E2 with respect to adsorption onto microcrystalline cellulose were examined. Cellulolytic enzymes were separated by gel fi ltration chromatography into a high-molecular-mass complex with an app arent mass of approximately 1,200 to 1,400 kDa and proteins of lower m olecular weights. Adsorption of cellulolytic enzymes was not only very fast (within 2 min, equilibrium was attained) but also very effective : Avicelase, endoglucanase, and beta-glucosidase activities from the h igh-molecular-mass complex were almost completely removed by Avicel. A dsorption of these enzyme activities was proportional and appeared to obey the Langmuir isotherm, For Avicelase, endoglucanase, and beta-glu cosidase activities, the maximum amounts adsorbed (A(max)) and apparen t adsorption constants (K-ad) were 16.8, 600, and 33.5 IU/g and 284, 6 .93 and 126 ml/IU, respectively, The results of this study strongly su pport the existence of a multiprotein enzyme complex. This complex was found not to be specifically associated with cell wall fragments as j udged by chitin determination.