The heat out -put of metablism of different bacillus thuringiensis has been studied by means of microcalorimetry. The experimental strains were a wild type (YBT-1463) and engineering type (BMB160, bmb171, BMB-304-171-A, BMB-304-171-B). YBT-1463 contains fourteen plasmids, BMB160 contains six plasmids but no insecticidal crystal protein. BMB171 have neither plasmids nor insectividal crystal protein gene. BMB-304-171 -A and BMB-304-171- B each havew a insecticidal crystak protein gene , one is the gene of cryⅠ Ac the other is ctyⅠC. The experimental data show that the heat out -put of metabolism of BMB171 is much more than that of YBT-1463 and BMB160, and the metabolic heats of BMB-304-171-A and BMB-304-171-B are also less than that BMB171. These results indicate that the endogenuous plasmids have great effect on the metabolism of Bacillus thuringiensis. It is the same for the genes which are tranformed into BMB171. sime there is no much difference between the genes of cryⅠAc and ctyⅠC, there is no dramatic change in thermokinetism. The first report of the thermokinetism in Bacillus thuringensis is benficial to the control of fermention .

Key words: MICROCALORIMETRIC METHOD, INSECTICIDES, NGINEERED BACTERIA