The maintenance energy of bacteria in growing cultures

The variation, with growth rate, of the yield of organism from the substrate used as energy source is attributed to consumption of energy at a constant rate for cell maintenance. From the laws of growth, a simple relation between the maintenance requirement, the growth yield and the growth rate is derived. The relation is shown to be in good agreement with the available data. A distinction is made between ‘observed’ yield and ‘true’ yield of organisms. Values for maintenance energies and ‘true growth yields’ have been calculated from the data.