Free and cell-bound cellulase activity of Cellulomonas flavigena

Free beta-1, 4-glucanase activity was measured in the supernatant of cultures of Cellulomonas flavigena grown on carboxymethylcellulose or filter paper as the main carbon source. Filtration through a series of filter papers resulted in quantitative removal of the enzyme from the supernatant. The glucanase was found to be tightly bound to the paper. Cellobiose was produced from the filters containing the enzyme, when incubated at 40 degrees C. After removal of the bacterial cells the paper remnants of a C. flavigena culture also formed cellobiose. Apparently beta-1, 4-glucanase is freed into solution after the paper has been partially degraded. This release is a consequence of the decreasing ratio of cellulose to enzyme. Some glucosidase activity could be detected in the supernatant of stationary phase cultures. This was probably the result of some cell lysis. However, high activities could be measured in ultrasonic cell debris. This suggests that the beta-glucosidase of C. flavigena, contrary to beta-1, 4-glucanase, is cell-bound.