Editorial

Abstract

The study of quantitative aspects of growth and metabolism in microorganisms started in 1950 with the classical work of Monod. In his paper the yield factor was defined, and further it contained the equation which gives the relation between the rate of substrate uptake and substrate concentration. In 1960 the relation was laid between the yield factor and the ATP production during substrate breakdown. Subsequently rapid progress was made because of the introduction of continuous cultivation in the chemostat. This led to the realization that the yield factor was dependent on the specific growth rate and to the introduction of the maintenance concept. In the early seventies theoretical calculations were performed on the amount of ATP required for the formation of cellular material and of the major macromolecules in the microbial cell. This also led to the realization that Y_ATP is not a constant and is dependent on the nature of the growth substrate, the pathway of its breakdown and the specific growth rate. An important new development was then the introduction of the method for material balancing during bacterial growth. At the same time calculations on the thermodynamic efficiency of microbial growth started to be a matter of study. Afterwards non-equilibrium thermodynamics, first utilized to describe the bioenergetics of mitochondria, were applied to microbial growth and this led to a new method for the description of microbial growth.