What is the mechanism of oxygen uptake in E. coli?
This question got me thinking about what are the metabolic enzymes that take oxygen up in E.coli. I searched the metacyc database for reactions that consume molecular oxygen and there are only 3 that take in oxygen and one that produces oxygen. 

All three consumers of oxygen in E.coli are the oxidation of ubiquinone by at two sites in cytochrome-bcl or by cytochrome-bo.  All of these export protons to create the gradient that drives ATP formation by F₀F₁ ATPase in the periplasm (the region between E.coli 's inner and outer membrane). 



On the production side, superoxide dismutase reduces superoxide to oxygen to control oxidation damage.  Apparently the innards of E.coli are somewhat oxygen tolerant.