Isolation of Nitrifying Organisms and Oxygen Supply

Abstract

IN a communication, “Isolation of the Nitrifying Organisms from Soil”¹, Dr. Howard Lees stated that he believed that he obtained a pure culture of Nitrosomonas with his percolator method. The only one who, so far, has got a pure culture of Nitrosomonas without any microbiological technique has been Bonazzi. Lees ascribes the success of this technique to the good aeration the percolator method provides to the culture. Bonazzi also aerated his cultures, but he hesitates to ascribe his success only to aeration. This experience led Lees to the conclusion that the well-known difficulties encountered in getting pure cultures of the nitrifiers were due to a lack of oxygen supply. This view he tries to justify by referring to correct figures on oxygen consumption of nitrifying cultures and diffusion-rate of oxygen taken respectively from Stephenson and Höber.