Identification of rumen bacteria that anaerobically degrade nitrite

Abstract

Fifty-one pure strains of rumen bacteria, representing 15 genera, were tested for their ability to metabolize nitrite. Twenty-five of the strains, belonging to eight genera, were capable of growth and nitrite metabolism in nitrite-containing medium sterilized by autoclaving. An additional 10 strains showed growth and nitrite metabolism in medium that was autoclaved before the addition of filter-sterilized nitrite. Nitrite metabolism was not observed in the remaining 16 strains, and these were also incapable of growth in the presence of nitrite. Ammonia was produced during nitrite reduction by Megasphaera elsdenii J1. In agreement with previous studies, abiotic losses of nitrite were observed during autoclaving and storage of media, but losses of nitrite due to bacterial metabolism were much greater.