CALORIMETRIC OPTIMIZATION OF GROWTH AND SPORULATION OF BACILLUS-THURINGIENSIS VAR GALLERIAE

Results from the investigation of the cultivation of Bacillus thuringi ensis var galleriae in a bench-scale calorimeter (Bio-RCl) are present ed in this work. On-line torque measurements were used to correct the baseline shift resulting from the variation of rheological properties of the medium. Heat measurements, combining with the balances of mass, degree of reduction and energy, are used to estimate the consumption of yeast extract, thus more accurate stoichiometry of the growth react ion in semi-defined medium was determined. The correlations between th e rate of heat production and other relevant process variables, during the growth of B.t.g., were explored, and such correlations and stoich iometry of growth form the basis for using on-line data of heat produc tion, together with other continuously measured information, for the o ptimization of media and the monitoring and control of the growth and sporulation processes of B.t.g., particularly in fed-batch and continu ous cultures. (C) 1998 Elsevier Science B.V.