High potential of tellurite bioremediation by moderately halophilic Staphylococcus xylosus

Abstract

The use of bacteria has been considered as a suitable alternative for metalloids remediation. We isolated 84 tellurite-resistant bacteria, and characterized tellurite-resistant and tellurite-reducing bacterial strains from samples collected in Iran. We report here a halophilic Gram-positive strain can tolerate and accumulate equal to 26.39 mM (6598.66 µg/ml) concentrations of potassium tellurite from media. This strain were identified according to the 16S rRNA gene sequence as Staphylococcus xylosus. Here we show for the first time that S. xylosus can be efficiently remediate K2TeO3. Cell aggregation in the presence of tellurite was visually observed by colony color changes to black in media. Reduction of Te to Te0 determined with the spectrophotometric measurement method and sodium diethyldithiocarbamate trihydrate reagent (DDTC, A340nm). In order to provide high tellurite remediation, the optimum growth conditions of this bacterium were determined. The best terms are included 0.4 mM of oxyanion, 40 °C growth temperature, pH 6–8, 400 mM NaCl, and 50 RPM under aerobic conditions. Resistant to tellurite and a high level of tellurite reduction by S. xylosus might be interesting for further industrial applications.