Energy Requirement for Microbial Growth

Abstract

MICRO-ORGANISMS provide good experimental material in the examination of energy requirements for the growth of living matter, because the supply of energy source may be readily controlled and the amount of growth easily determined. In 1942, Monod¹ reported on the growth of Bacillus subtilis, Escherichia coli and Salmonella typhimurium in a mineral medium with a wide range of carbohydrates as the source of energy. He found that, so long as the energy supply was the limiting factor for growth, the dry weight of the organisms produced (that is, growth) under anaerobic condition was proportional to the weight of the source of energy added. These findings were confirmed by DeMoss, Bard and Gunsalus². A comparison of the growth yields of different microorganisms was recently made by Bauchop and Elsden³ on the basis of dry weight produced per mole of adenosine triphosphate (ATP) formed during the catabolism of the energy-yielding substrates (Yield Coefficient^ATP or Y^ATP). In their experiments, which were also conducted under energy-limiting and anaerobic conditions, they found a striking agreement in the Y^ATP for a number of organisms, including Streptococcus faecalis, Saccharomyces cerevisiae and Pseudomonas lindneri. The mean of 8 values for Y^ATP is 10.5 g dry cells per mole of ATP (range, 8.3–12.6).