Low Temperature and Neutral pH Define “ Candidatus Nitrotoga sp.” as a Competitive Nitrite Oxidizer in Coculture with Nitrospira defluvii

Wegen et al. (2019). Applied and Environmental Microbiology 85 (9)
Names (1)
Ca. Nitrotoga
Applied Microbiology and Biotechnology Biotechnology Ecology Food Science
“ Ca. Nitrotoga” is a NOB of high environmental relevance, but physiological data exist for only a few representatives. Initially, it was detected in specialized niches of low temperature and low nitrite concentrations, but later on, its ubiquitous distribution revealed its critical role for N removal in engineered systems like WWTPs. In this study, we analyzed the competition between Nitrotoga and Nitrospira in bioreactors and identified conditions where the K strategist Ns. defluvii was almost replaced by Nitrotoga sp. BS. We show that the pH value is an important factor that regulates the composition of the nitrite-oxidizing enrichment with a dominance of Nitrotoga sp. BS versus Ns. defluvii at a neutral pH of 7.4 in combination with a temperature of 17°C. The physiological diversity of novel Nitrotoga cultures improves our knowledge about niche differentiation of NOB with regard to functional nitrification under suboptimal conditions.
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