Fibrobacter succinogenes S85 grew rapidly on cellobiose (0.31 h(-1) and the absolute rate of increase in fermentation acids was 0.68 h(-1). Cultures that were provided with ball-milled cellulose initially produced fermentation acids and microbial protein as fast as those provided with cellobiose, but the absolute cellulose digestion rate eventually declined. If the inoculum size was increased, the kinetics decayed from first to zero order (with respect to cells) even sooner, but in each case the absolute rate declined after only 20 to 30% of the cellulose had been fermented. Congo red binding indicated that the cellulose surface area of individual cellulose particles was not decreasing, and the transition of ball-milled cellulose digestion corresponded with the appearance of unbound cells in the culture supernatant. When bound cells from partially digested cellulose were removed and the cellulose was re-incubated with a fresh inoculum, the initial absolute fermentation rate was as high as the one observed for undigested cellulose and cellobiose. Based on these results, cellulose digestion by F. succinogenes S85 appears to be constrained by cellulose surface area rather than cellulase activity per se.

Alpha amylase production using microbial source and solid state fermentation has been conducted for past few years in search of thermostable enzyme. Owing to the prolific use of thermostable alpha amylase in various industries like paper, food, detergent, brewing and starch liquefaction process, the production of alpha amylase is still going on. In the present work, Bacillus subtilis (ATCC 6633) has been utilized for generation of alpha amylase followed by optimization of the fermentation media. Change in fermentation conditions like fermentation hour, temperature, inoculums size, nitrogen and sugar sources have pivotal role to enhance alpha amylase yield. The thermal, pH and detergent stability of partially purified alpha amylase have been tested and compared with purified porcine pancreatic amylase. The result is encouraging with approximate 80% retention of alpha amylase activity comparable to purified porcine pancreatic amylase in presence of drastic condition of temperature (60°C), pH (6-11) and detergents. This makes it apt for use in various industries like detergent, food and paper industries.