Tellurite resistance and reduction during aerobic and anaerobic growth of bacteria isolated from sarcheshme copper mine

ABSTRACT

Tellurium compounds can be found in high concentrations in land and water near sites of waste discharge of industrial manufacturing processes and anodic sludge of copper mine. Potassium tellurite [K2TeO3] is toxic to many microorganisms at concentrations >1mg/mL. In this research, some species of facultative anaerobic bacteria [Bacillus sp.] were isolated from Sarcheshme copper mine[Kerman, Iran] which demonstrated high-level-resistance to tellurite and accumulation of metallic tellurium crystals. High-level-resistance was observed for Bacilli and cocci grown with certain organic carbon sources, implying that tellurite reduction is not essential to confer tellurite resistance. Level of adsorption was determined by inductively coupled plasma and spectrophotometer [Diethyldithiocarbamate method]. The level of tellurite concentration in the bacteria cell and the formation of tellurium nanocrystals were illuminated by transmission electron microscope and scanning electron microscope. The Te[0] crystals occur internally and each microorganism forms a distinctly different structure [for example Bacillus selenitreducens make tellurium nano rod]. In this study it was found that microorganism can grow 3.in 1500mg/L-2000mg/L and higher tellurite concentrations. The use of microorganisms to generate Te nanomaterials may be an alternative for bench-scale syntheses. Additionally, they may also generate products with unique properties unattainable by conventional physical/chemical methods. This study is important because native bacteria from Sarcheshme [Kerman, Iran] that may show high-level-resistance to tellurite, were isolated