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Updated: Jan 25, 2026

Measuring Nitrite and Nitrate, Metabolites in the Nitric Oxide Pathway, in Biological Materials using the Chemiluminescence Method
Published on: December 25, 2016
Cobalt-dependent inhibition of nitrite oxidation in Nitrobacter winogradskyi
Richard Metzner1, Taiji Nomura1, Naoki Kitaoka1
1Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
Abstract:
Nitrobacter winogradskyi is an abundant, intensively studied autotrophic nitrite-oxidizing bacterium, which is frequently used as a model strain in the two-step nitrification of ammonia (NH3) to nitrate (NO3-) via nitrite (NO2-), either in activated sludge, agricultural field studies or more recently in artificial microbial consortia for organic hydroponics. We observed a hitherto unknown cobalt ion-dependent inhibition of cell growth and NO2- oxidation activity of N. winogradskyi in a mineral medium, which strongly depended on accompanying Ca2+ and Mg2+ concentrations. This inhibition was bacteriostatic, but susceptible to natural chelators. l-Histidine effectively restored cell growth and NO2- oxidation activity of N. winogradskyi in mineral media containing Co2+ with >90% recovery. Our results suggest that Co2+ competed with alkaline earth metals during uptake and that its toxicity was significantly reduced by complexation.
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