Pure isolation and characterization of a new chemoautotrophic nitrite-oxidizing bacterium, Nitrobacter sp. TH21

Abstract

A new nitrite-oxidizing bacterium, strain TH21 was isolated on a 10^4-fold diluted BE-medium agar plate by screening a total of 150 soil samples. The cells of strain TH21 were gram-negative, rod-shaped, 0.5-1.0×1.0-2.0μm in size, chemoautotrophic, obligately aerobic, and motile with a single subpolar flagellum. Cells reproduced by budding which is characteristic of the genus Nitrobacter. The G+C content of the DNA was 61.0 mol%. The optimum concentration of sodium nitrite for the growth of Nitrobacter agilis ATCC 14123 was 3 mM but not 7 mM. Strain TH21 was assigned as belonging to the genus Nitrobacter.