CLOSTRIDIUM CELLULOLYTICUM VIABILITY AND SPORULATION UNDER CELLOBIOSESTARVATION CONDITIONS

Depending on the moment of cellobiose starvation, Clostridium cellulol yticum cells behave in different ways, Cells starved during the expone ntial phase of growth sporulate at 30%, whereas exhaustion of the carb on substrate at the beginning of growth does not provoke cell sporulat ion, Growth in the presence of excess cellobiose generates 3% spores. The response of C. cellulolyticum to carbon starvation involves change s in proteolytic activities; higher activities (20% protein degradatio n) corresponded to a higher level of sporulation; lower proteolysis (5 %) was observed in cells starved during the beginning of exponential g rowth, when sporulation was not observed; with an excess of cellobiose , an intermediate value (10%), accompanied by a low level of sporulati on, was observed in cells taken at the end of the exponential growth p hase. The basal percentage of the protein breakdown in nonstarved cult ure was 4%. Cells lacking proteolytic activities failed to induce spor ulation. High concentrations of cellobiose repressed proteolytic activ ities and sporulation. The onset of carbon starvation during the growt h phase affected the survival response of C. cellulolyticum via the sp orulation process and also via cell-cellulose interaction, Cells from the exponential growth phase were more adhesive to filter paper than c ells from the stationary growth phase but less than cells from the lat e stationary growth phase.