microaerobic growth capabilities? To derive energy as obligate,nonphototrophic aerobes, microaerophilic bacteria
must oxidize substrate and involve oxidative phosphorylation.Experimentally, considerable variation in the choice
in limiting-O2 conditions has resulted in different assumptionsabout “microaerobic” growth conditions and, often,
quite disparate inferences. For microaerophilic bacteria, thekey requirement of microaerobic physiology is conceptually
straightforward: a DOT insufficient to sustain the cytochromeaa3 (oxidase) activity of conventional aerobic
organisms. However, DOT is normally measured potentiometrically in aqueous phases whereas the lipid phases of
biological membranes in which O2 is relatively more soluble