Estudo e prospecção de bactérias anammox para aplicação em tratamento de efluentes de aquicultura

Abstract

Anaerobic oxidation of ammonium (anammox) is a microbial pathway that can simultaneously remove ammonium and nitrite through bacteria that take a shortcut in the nitrogen cycle. These bacteria have the potential to mitigate polluted environments, including the treatment of aquaculture effluents that are rich in nitrogenous compounds. Considering these facts, the objective of this research was to carry out prospection and isolation of aerotolerant bacteria with anammox activity in continental aquatic ecosystem (CAE) as a basis for biotechnological process development, to improve the quality of the effluent from aquatic organisms through the reduction of total ammoniacal nitrogen. Water and sediment samples were collected at three points of the Santo Anastácio Dam (Fortaleza - CE). These samples were enriched with a selective mineral broth for anammox bacteria (M1) and placed in an anaerobic jar for seven days. After dilutions, the samples were inoculated using the Pour Plate technique in anammox selective culture medium (M2) and another non-selective medium (M3). Then, Standard Plate Counting (SPC), isolation, and Gram staining were performed. It was witnessed that the growth of bacterial colonyforming units (CFU) was higher in the samples inoculated in the M3 medium. Also, in both M2 and M3 media, the sediment samples had the highest amount of bacteria: 2,22 x 105CFU/g and 7,15 x 106 CFU/g, respectively. Twenty-seven bacterial strains were isolated, using the criterion of being air tolerant and growing in up to five days. Of the strains identified, 74% were isolated from the M2 medium and 26% from the M3 medium. Most strains showed Gram-positive rod morphology and were separate from sediment samples.