Identification and removal condition of a nitrite removing bacterium from aquaculture sediment

Abstract:

[Objective] The aim of the present study was to isolate and screen potential nitrite removal bacteria, and examined the nitrite removal conditions. [Methods] Nitrite removal bacteria were first isolated from the aquaculture sediment, and the potential nitrite removal isolate was further screened through the nitrite removal rate comparison, identified using API ID32GN bacterial identification system and 16S rDNA sequence analysis, and its nitrite removal conditions were studied using single factor method. [Results] A potential nitrite removal bacterium AQ-3 was isolated and screened from the aquaculture sediment, its removal rate to 50 mg/L nitrite was 99.47%. Strain AQ-3 was identified as Acinetobacter baumannii (GenBank accession number: JF751054.1). Its 16S rDNA sequence had homology of 99%?100% with those of Acinetobacter sp. strains submitted to GenBank, and showed the most close relative to Acinetobacter baumannii strain KF714 (GenBank accession number: AB109775). The optimum initial pH range for the nitrite removal of strain AQ-3 was from 7 to 9, and the optimum carbon sources for its nitrite removal were sodium acetate and sodium succinate. In addition, the nitrite removal rates of strain AQ-3 were gradually rising with the increase of its initial bacterial concentrations, and the nitrite removal rates were gradually reduced with the increase of nitrite content. [Conclusion] The present study enriched the resources of nitrite removal bacteria and provide scientific basis to the practical use of strain AQ-3 in aquaculture.