2005 Volume 20 Issue 4 Pages 208-215
A novel aerobic denitrifier, designated strain NH-14, was isolated from soil collected in Tsukuba, Japan. Strain NH-14 could reduce nitrite (NO2-) to nitrous oxide (N2O) under aerobic and anaerobic conditions. The conversion of NO2- to N2O occurred under extremely aerobic conditions (O2 concentration: 4.2 mmol flask-1), and was induced by NO2-, indicating aerobic denitrification. From the biochemical characterization and phylogenic analysis of the complete 16S rRNA gene, strain NH-14 was shown to belong to the genus Mesorhizobium with M. loti and M. amorphae as its closest relatives. The strain was designated Mesorhizobium sp. strain NH-14. It was concluded that Mesorhizobium sp. strain NH-14 is capable of denitrification under both aerobic and anaerobic conditions.