Nitrite formation by soil bacteria, other than Nitrosomonas

The biological nature of nitrification in soil was first established by Schlösing and Müntz (1877). Warington (1878, etc.) at Rothamsted and numerous other investigators elsewhere advanced considerably the knowledge of this process. Winogradsky (1890) first succeeded in isolating two species of bacteria, one capable of oxidising ammonia into nitrite and the other nitrite into nitrate; he further showed that nitrification in soil can take place only through the activity of a very limited group of autotrophic bacteria possessing the peculiar property of growing exclusively in an inorganic medium having a very prononced alkaline reaction. In 'Nature' Cutler (1930) reported that several different bacterial strains capable of oxidising various ammonium salts to nitrite had been isolated from different sources. A description of some of these bacteria occurring in soil, together with their physiological reactions, is given in this paper.