BACTERIAL CALORIMETRY II. RELATIONSHIP OF HEAT PRODUCTION TO PHASES OF GROWTH OF BACTERIA

Abstract

By simultaneous observations of heat production by bacteria, and enumeration of the organisms in the culture, it is possible to correlate growth curves with curves of heat liberation. A combination of such observations with those of the morphological changes and life-phases of bacteria yields some information as to the metabolic activities of a culture at various periods. By use of Buchanan''s formula, the rate of heat production by a single bacterial cell can be calculated, and the observed values agree closely with those derived by this calculation. Changes in rate of heat production are related to changes in growth rate of acteria. Young bacterial cells produce more heat per cell than older ones. After about the 5th hr. of growth, heat production reaches a low level and remains constant, suggesting the existence of a basal metabolic rate during that period.