Heterotrophic nitrifying/aerobic denitrifying bacteria: Ammonium removal under different physical-chemical conditions and molecular characterization

Biological ammonium removal via heterotrophic nitrification/aerobic denitrification (HN/AD) was characterized for two isolates from a wastewater treatment station (WWTS). They were identified as Pseudomonas balearica UFV3 and Gordonia anticalis UFV4. Their ability to remove ammonium via NH/DA was validated by chromatography, and the influence of different physical-chemical factors on removal was evaluated. The presence of genes involved in conventional nitrification and denitrification processes was investigated via PCR and comparative genomics. Both isolates removed 100% of the ammonium in a medium containing citrate as its carbon source with a C/N ratio of 8, 3% salt, pH 7 and 30 degrees C. Nitrogen balance showed that approximately 55% of the ammonium removed was lost as N-2((g)), and 45% was assimilated. Molecular characterization revealed the absence of genes involved in autotrophic nitrification in the genome of the two isolates and the presence of genes involved in anaerobic denitrification only in P. balearica UFV3, suggesting the involvement of other genes in the HN/AD process. This was the first report of G. amicalis and P. balearica with the capability for HN/AD248CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGsem informaçãosem informaçãosem informação8603-4600391375PETRÓLEO BRASILEIRO S. A. - PETROBRA