TY - JOUR AU - Rodríguez Rodríguez, Abad AU - Mau Inchaustegui, Silvia AU - Piedra Castro, Lilliana AU - Jiménez Montealegre, Ricardo AU - Herrera Vargas, Juan Pablo PY - 2017/12/01 Y2 - 2024/03/28 TI - Isolation of ammonium- and nitrite-oxidizing bacterial strains from soil, and their potential use in the reduction of nitrogen in household waste water JF - Revista de Biología Tropical JA - Rev. Biol. Trop. VL - 65 IS - 4 SE - Articles DO - 10.15517/rbt.v65i4.26509 UR - https://revistas.ucr.ac.cr/index.php/rbt/article/view/26509 SP - 1527–1539 AB - <p>Currently, nitrogen has become the main element of water pollution, causing riverine, lacustrine and coastal eutrophication. The continuous contamination of aquifers and the absence of planned water resource utilization, boost its scarcity, and has been the only way in which our societies become aware of the urgent need to process the generated wastewater. The objective of this research was to evaluate the nitrifying capacity of different autochthonous bacterial isolates from soils from nearby sources of domestic wastewater drainage. For this, bacteria were isolated from Pirro River, contaminated with nitrogen of domestic sewage. Nitrifying bacteria were counted by serial dilution and agar plates, and were isolated until obtaining axenic colonies. These were identified by biochemical batteries or genetic sequencing, and the quantification of their nitrifying capacity was obtained by the methods 4500- NH4 + -F and 4500-NO-2-B, all between September 26, 2011 and March 16, 2014. A total of seven strains of nitrifying microorganisms were isolated and purified, including four <em>Streptomyces</em> sp., one <em>Pseudomonas putida</em>, one <em>Sphingomonas</em> sp. and one <em>Aeromonas</em> sp. We found that there were 2.23 x 10<sup>5</sup> UFC/g of soil of ammonium oxidizing bacteria and 2.2 x 10<sup>4</sup> CFU/g of soil of nitrite oxidizing bacteria in the samples. The quantification of the nitrifying capacity of the strains by colorimetric methods, determined that the maximum ammonium removal capacity was 0.050 mg N/L/day and 0.903 mg N/L/day of nitrite. The collection of few strains of nitrifying organisms and a low CFU count, can be attributed to the technique used, since this only recovers 1 % of the microorganisms present in a sample, which, however, is acceptable for studies which main purpose is to obtain cultivable microorganisms. Future research should consider removal tests with higher ammonium and nitrite levels, to find the maximum capacity of the isolated microorganisms, and evaluate their potential use in wastewater treatment systems.</p> ER -