After a short review of the development of biological calorimetry and a discussion of the instrumentation and the measuring principles that have been applied to study heat generation by microbial cultures and other cellular systems, this article demonstrates how heat evolution depends on growth, biomass yield, maintenance metabolism, nature of substrate, energetic efficiency of growth, oxygen uptake, and product formation. Theoretical considerations are used together with experimental evidence to explain the nature of these relationships and the underlying reasons. The possibilities of exploiting these relationships in order to gain information on any of the above factors by applying calorimetric measurements to biotechnology have been emphasized and developed throughout this paper.

The use of calorimetry in biotechnology

Large-scale calorimetry and biotechnology

Heat transfer and power measurements in stirred tanks using heat flow calorimetry

Isothermal reaction calorimeters—I. A literature review

Measurements of the heat produced by Saccharomyces cerevisiae CBS 426 were used in conjunction with elemental and enthalpic balances to control fed-batch fermentations. A proportional control using the ratio of carbon dioxide evolution rate to heat production resulted in high biomass yields and minimal ethanol production. For the special case where the carbon source contains no nitrogen, biomass production estimated from heat measurements agreed well with measured values. When the controller gain was set below the maximum specific cellular growth rate, stable control was achieved, even in response to large upsets in feed concentrations.

W. Regenass

Papers

Thermoanalytische methoden in der chemischen verfahrensentwicklung