CELLULASE COMPLEX OF A NEW HALOPHILIC BACTERIUM HALOCELLA-CELLULOLYTICA

We studied the cellulase from a new anaerobic, halophilic, cellulolyti c bacterium, Halocella cellulolytica. The organism exhibited optimal g rowth at a salinity of 2.6 M NaCl, a temperature of 39-degrees-C, and with cellulose or cellobiose as a carbon source. The cellulolytic acti vity of this strain was of the same order of magnitude as those of non -halophilic bacteria. The distribution of endoglucanase and cellobiase activities between the cells and medium depended on the age of the cu lture and on the nature of the carbon source. Optimal activity of endo glucanase was observed at medium pH 7.5 and NaCl concentration 0.5 M. Half-time for the heat-inactivation of the cellulase at 50-degrees-C w as 68 min. The shape of adsorption isotherms indicated the presence of only one endoglucanase in the bacterial cellulase complex. The abilit y of the endoglucanase to adsorb to cellulose depended on the nature o f the carbon source in the growth medium and was a function of the Hen ry constant of adsorption equilibrium, which amounted to 0.6 and 0.05 liters/g for cells grown on filter paper and cellobiose, respectively.