عنوان مقاله [English]
The extensive use of tellurium oxyanions, such as Tellurite,in various industries such as textile, tanning and plating ,which are highly toxic to microorganisms and eukaryotes , has increased environmental pollution. Potential application of Tellurite oxyanions bioreduction in resistant bacteria in surroundings can be a valuable tool in biotechnology for Biological removing of tellurite from contaminated areas by microorganisms.
84 strains of resistant bacteria to tellurite was separated from industry's wastewater. Tellurite resistance activity was evaluated using the minimum inhibitory concentration (MIC)method, concentration 0/1 to26mM potassium tellurite at 34°C for 7 days by the agar dilution method and QWTmb9 was isolated which able to tolerate and reduction very high concentration of 22 mM. This tolerance to tellurite compared with the threshold concentration of other isolated bacteria is remarkable. In order to evaluate strain's Tellurite removal, colorimetric method using a spectrophotometer and DDTC reagent (sodium-diethyldithiocarbamatetri-hydrate, A340 nm) was used.
The effects of various factors on the optimal growth and tellurite removal were investigated conditions Tellurite concentration, pH, temperature, aeration rate and different concentrations of NaCl. Due to the direct connection to oxyanions resistance and resistance to antibiotics, Antibiogram test was conducted.
QWTmb9 isolated from wastewater of blanket textile, which maximum removal rates in 24h is in 0.4 concentrations of Tellurite, temperature 35°C, pH7.5 , 100RPM aeration and 170mM NaCl concentration. This strain is resistant to antibiotics penicillin, ampicillin, rifampin, tetracycline, chloramphenicol, neomycin, kanamycin and erythromycin.
Gram-negative strains QWTmb9 can be a good candidate for elimination of toxic tellurite in industrial biotechnology.