Acetylene Reduction by Klebsiella pneumoniae in Air Related to Colony Dimorphism on Low Fixed Nitrogen

Until recently it was believed that Klebsiella pneumoniae fixed nitrogen only under anaerobic conditions (see Postgate, 1971). However, Klucus (1972) showed that a species of Klebsiella produced active nitrogenase in the presence of 0, in a chemostat culture provided that the medium contained yeast extract (I g/l) as a fixed N source and the dissolved oxyge