Isolation, identification and characterization of nitroso-bacteria in one-step completely nitrogen removal process

Abstract:

[Objective] To study the characteristics of the Nitroso-bacteria in one-step completely autotrophic nitrogen removal process. [Methods] We took samples from activated sludge of the one-step completely autotrophic nitrogen removal reactor. Through four times of enrichments and isolations, one Nitroso-bacteria named N1 was obtained. We identified this strain by microscope and 16S rDNA analysis and studied the effect of pH, temperature as well as ammonium concentration on the metabolism of N1. [Results] Of the N1 nucleotides, 97%, 96% and 96% were identical with the conserved fragment of Nitrosomonas sp. NL7 (AY958677), Nitrosomonas AS1 (EF016119) and Nitrosomonas sp. Is32 (AJ621027) respectively. The optimal temperature and pH of N1 were 8.0 and 30℃ and sufficient dissolved oxygen was demanded. In addition, no restraint effect was turned up in the ammonium concentration of 80-800 mg/L. [Conclusion] N1 was identified as Nitrosomonas sp. Compared with the relative references, this strain was ammonium-tolerant.