Abstract

RANGEL-MONTOYA, Edelweiss A.  and  BALAGURUSAMY, Nagamani. Bioprospecting arsenite oxidizing bacteria in the soil of the Comarca Lagunera. Rev. Chapingo ser. cienc. for. ambient [online]. 2015, vol.21, n.1, pp.41-56. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2014.05.024.

Arsenic is one of the most toxic metalloids present in the environment and prolonged exposure to this metal causes chronic health effects. Therefore, the search for environmentally-friendly alternatives for the treatment of arsenic-contaminated water and soil is important. In this study, bacterial strains were isolated from arsenic-containing soils in the Lagunera region to analyze those with arsenite-oxidizing abiliity. Strains 04-SP1qa and 14-SP1qh with chemolithoautotrophic and chemoheterotrophic metabolism, respectively, had greater activity of the arsenite oxidase enzyme. The optimum growth conditions and enzymatic activity of these strains were investigated. Strain 04-SP1qa had specific enzymatic activity of 0.162 μmol·min^-1·mg^-1, Michaelis-Menten constant (K_m) of 3.37 μM and maximum velocity (V_max) of 5.20 μM·min^-1·mg^-1 under optimum growth conditions of pH 8.0 at 40 °C. Strain 14-SP1qh showed specific enzymatic activity of 0.16 μmol·min^-1·mg¹, K_m of 3.70 μM and V_max of 14.39 μM·min^-1·mg-¹ at pH 7.0 and 40 °C. Results of this study demonstrated the presence of arsenite- oxidizing bacteria with enzymatic activity in the soils of the Lagunera region. Thus, the potential exists to develop new bioremediation technologies for treatment of arsenic-contaminated water and soils in the region using native bacterial strains.

Keywords : Arsenite oxidase; chemolithoautotrophic; chemoheterotrophic; bioremediation.

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