Real time insights into bioprocesses using calorimetry: State of the art and potential

The potential of calorimetry is analyzed to give insights into dynamic biological processes and to use this information to control technical and natural systems. The first part explains how calorimetry provides information of the stoichiometry and metabolic fluxes of microbial processes. Changing heat production reflects metabolic shifts in real time while being measurably non-invasive. Applying the first law of thermodynamics, calorimetry permits to test whether process heat is in accordance with assumed metabolic pathways and to detect unknown reactions. Possible reasons for the negligence of this powerful technique by those being involved in biochemical research or those dealing with controlling processes are discussed and optimal measurement principles for different purposes are proposed. The second part introduces technically applicable measurement principles, their peculiarities and consequences for the elucidation of stoichiometry and bioprocess control. The paper concludes with an outlook to the future of calorimetry as a scientific tool and in technical applications.