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| Isolation and identification of an efficiently heterotrophic nitrifier, and its removal characterization of ammonia nitrogen |
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Abstract A heterotrophic nitrifying bacteria isolated from the activated sludge of landfill leachate through the enrichment medium with sodium succinate as the sole carbon source was identified by its morphologic observation and the analysis of physiological characteristics and 16S rDNA sequence; its nitrifying function and removal characterization of ammonia nitrogen were also studied in this paper. This strain was identified as Pseudomonas sp., named as XS76 with JQ934897 as its GenBank accession number. After 24h-cultivation, nearly 60% ammonia nitrogen was converted into intracellular nitrogen and 35% removed. There was only a small amount of nitrate nitrogen accumulation, but with no accumulation of hydroxylamine and nitrite nitrogen. The factors including carbon source, organic nitrogen, C/N and cultivation temperature were important for the removal of ammonia nitrogen. The optimum condition for heterotrophic nitrification was as follows: sodium succinate as the carbon source, ammonium sulfate as its nitrogen source, C/N ratio of 15, shaking speed of 180~200r/min, pH of 6~9, culture temperature of 34℃ and the initial ammonia nitrogen of 420 mg/L. After 96h-cultivation under the optimum condition, the removal rate of ammonia nitrogen reached 99.20% high. Hence, XS76 could have high potential in practical wastewater treatment.
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Received: 18 November 2012
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