Culture of Nitrosomonas europaea in Media Free of Insoluble Constituents

Abstract

SINCE Winogradsky's discovery of Nitrosomonas in the latter part of the nineteenth century, members of this genus have been grown in a variety of culture media containing insoluble constituents, the most common of these being calcium carbonate. This component serves as a means of pH control necessary because of the accumulation of large amounts of nitrous acid and also can provide the inorganic carbon source necessary for the autotrophic metabolism of these bacteria. Eventually, it was tacitly assumed that these micro-organisms require adsorption to particulate medium ingredients in order for active proliferation to occur^1,2. This phenomenon takes on practical significance for soil nitrification in view of the demonstration that substrate ammonium apparently must first be adsorbed before oxidation can commence³.