SCALE-UP OF BACILLUS-THURINGIENSIS FERMENTATION BASED ON OXYGEN-TRANSFER

A correlation between spore productivity and k(L)a, was found for Baci llus thuringiensis var. kurstaki. Since insecticidal crystal proteins synthesis depends on the highly oxygen-dependent sporulation process, the fermentation process was scale-up on the basis of the product k(L) a p, where p is the fermenter total pressure. The process was scale-up from a 14-l fermenter to a 1,100-l fermenter. Both reactors did not h ave the same geometrical design. Even though the specific growth rate decreased with the change of scale, the scale-up had a positive effect , since the total fermentation time was decreased white the biomass yi eld and the sporulation efficiency were unchanged. Therefore k(L)a p i s a practical tool for scaling up B. thuringiensis processes where pro duct synthesis depends on sporulation.