Evaluación de la degradación de arsénico con cepas bacterianas aisladas de relaves mineros, en el Cantón Ponce Enríquez

Abstract

The aim of this study was to assess degradation of arsenic with bacterial strains isolates from mine tailings at Ponce Enriquez Canton in Azuay province. From tailings samples 47 bacterial strains were isolated and tested for resistance arsenic, for which it was used as culture medium Oxytetracycline Glucose Yeast Extract (OGYE) agar Bacto adding arsenic and arsenate in different concentrations. Oxidation capacity or reduction of arsenic was assessed by qualitative test with silver nitrate. The description was performed using biochemical test system with 64 and 65 Microgen identification (MID). It was obtained 8 strains that resisted 30mM of arsenic and arsenate concentrations, these were identified as a gram negative bacillus from Pseudomonas, Pasteurella and Vibrio. The 100% of bacteria were able to reduce arsenate to arsenite in a period of 5 days. It concluded that isolated bacteria are extremotolerant due to its growth on a medium containing high levels of arsenic, which can also reduce as a detoxification process. It is recommended to continue identifying arsenic resistant bacteria in order to understand their role in the environment and its possible applications in biotechnology treatments.