An acidophilic and a neutrophilic Nitrobacter strain isolated from the numerically predominant nitrite-oxidizing population of an acid forest soil

Abstract

Two physiologically, serologically distinct strains of chemoautotrophic nitrite-oxidizing bacteria were isolated as numerically predominant members of the nitrite-oxidizer population of an undisturbed forest soil from an undisturbed 50-yr old mixed oak stand in the Hoosier National Forest, S Indiana, with a pH range of 4.3-5.2. One isolate responded as a neutrophile, characteristic of the family Nitrobacteraceae, and cross-reacted strongly with fluorescent antibody to Nitrobacter strain Engel. The 2nd isolate responded as an acidophile in pure culture, demonstrated maximal nitrite oxidation activity at pH 5.5 and had a pH tolerance range of pH 4.1-7.2. -from Authors