Bio calorimeter, fabricate and attempt to improve the sensitivity of calorimetric signals in the following ways: High sensitive RTDs (1mK) were installed in both reactor and jacket side and a robust temperature control strategy elicits response even there was a step change of 1mK in the reactor. Effect of ambient temperature fluctuations on the estimated calorimetric signals was reduced by insulating the jacketed surface by a vacuum and the heat loss through head plate was minimized by thermo stating it to the reactor operational temperature.