Characterization of the Aerobic Denitrification in Mesorhizobium sp. Strain NH-14 in Comparison with that in Related Rhizobia

Abstract

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. © 2005, Japanese Society of Microbial Ecology & The Japanese Society of Soil Microbiology. All rights reserved.