Use of chemostat for enhanced production of beta-glucosidase by newly isolated anaerobic cellulolytic Clostridium strain RT9

A new anaerobic, mesophilic, spore-forming, cellulolytic Clostridium strain, RT9, was isolated from bovine rumen fluid. The bacterium also exhibited endoglucanase, exoglucanase, and beta -glucosidase activities in batch culture during growth on chemically defined medium with cellulose as the sole carbon source. Chemostat experiments were conducted under pH, dilution rate, and carbohydrate limitations to study the effect of various parameters on enzymes and product formation. In chemostat with 0.5% cellobiose as the limiting nutrient, maximum beta -glucosidase activity and ethanol production occurred at pH values of 5.5 and 6.5, respectively. At low pH, acid accumulation was higher. beta -glucosidase production increased up to 17-fold at low dilution rate, and ethanol raised twofold.