Cellobiose: A true inducer of cellulosome in different strains ofClostridium thermocellum

Growth and production of cellulosome by three strains (YS, LQRI and NCIB 10682) of Clostridium thermocellum were compared using Avicel (microcrystalline cellulose) and cellobiose as carbon sources. All three strains grew faster on cellobiose than on Avicel and produced 0.71–0.74 IU of endoglucanase/ml compared to 0.88–1.18 IU/ml on Avicel. Also, the cellulase produced by these strains in the presence of 0.2–1% cellobiose and Avicel, when compared on the basis of equal units of endoglucanase (0.5 IU), degraded cotton almost completely. SDS-PAGE further confirmed the production of cellulosome by all three strains when grown on cellobiose and Avicel. Thus, the cellobiose, like Avicel, acts as a true inducer of cellulosome in C. thermocellum.