Cultivation and characterization of an ammonia oxidizing archaeon enriched from wastewater treatment plant

Abstract:

Abstract:［Objectives］ To enrich ammonia-oxidizing archaeon (AOA) from wastewater treatment plants，identify its phylogenetic status，morphology and determine its growth and ammonia oxidation rates． ［Methods］AOA was enriched in autotrophic medium containing antibiotics by using consecutive passage． The purity，uniformity and phylogenetic status of archaeal enrichment were determined with different molecular tools． The morphology was determined with scanning electron microscopy． The AOA growth andammonia oxidation rates were calculated from the corresponding experimental results.［Results］An AOA enrichment HJ-2b with purity of 93% was obtained． The similarity of its 16S rＲNA gene with Nitrososphaera sp．JG1 was 100%，suggesting it belonged to Nitrososphaera spp., although the similarity of amoA gene between these two species was only 72%． HJ-2b cell was rod-shaped，with the maximum specific growth rate of 0.43 d－1，the specific ammonia-oxidation rate of 3. 9 fmol/(cell·d).［Conclusions］HJ-2b has great significance in studying the occurrence and contribution of AOA in wastewater treatment.

Key words:Keywords: wastewater treatment plant，ammonia-oxidizing archaea，enrichment，specific growth rate，specific ammonia oxidation rate