Energy Production During Nitrate Respiration by Aerobacter aerogenes

Abstract

The molar growth yield of A. aerogenes growing anaerobically with glucose in a mineral medium was almost doubled when NO3 - was added as hydrogen acceptor. About half a mole of NO3 - was reduced to NH4 + per mole of glucose. The amount of ATP produced from glucose fermentation calculated from the molar growth yield and the acetate production was about 3 moles ATP/mole glucose. The total amount of ATP produced, deduced from the molar growth yield, was used to calculate that about moles ATP were produced per mole of NO3 - reduced. Comparable experiments with mannitol as carbon source gave the same results. When nitrite was used as hydrogen acceptor the anaerobic molar growth yield was the same or even smaller than in its absence, although the acetate production increased. The results suggest that during NO2 - reduction no ATP is produced and that the ATP formed during reduction of NO3 - to NH4 + is completely produced during the reduction of NO3 - to NO2 -.