RELATION BETWEEN ENERGY PRODUCTION AND GROWTH OF AEROBACTER AEROGENES.

Abstract

Summary: Molar growth yields were measured for Aerobacter aerogenes growing with a number of substrates as sole carbon and energy source in a minimal medium. Under anaerobic conditions the molar growth yield for glucose was 26·1 g. This amount of dry weight is produced at the expense of 2·55 mole of ATP (1·71 mole from glycolysis and 0·84 mole from acetate produced from pyruvate by the thioclastic reaction). The yield per mole ATP is thus 10·2 g., which value is very close to the one found for other micro-organisms. Under aerobic conditions the molar growth yield for glucose is 72·7 g. During growth 1·14 mole of O2 are taken up. The yield per atom oxygen is thus 31·9 g. By dividing the yield per atom oxygen by the yield per mole ATP we find the number of ATP mole formed per atom O. The values found are very close to 3, indicating that the efficiency of oxidative phosphorylation in this organism is the same as that in mitochondria. During the experiments it was observed that growth was maximal before the maximal O2 uptake was reached. The explanation is that during aerobic growth acetate accumulates, which is oxidized after maximal growth. Acetate oxidation after glucose consumption does not contribute to the dry weight.