Reduction of antibiotics using microorganisms containing glutathione S-transferases under immobilized conditions

The degradation of several antibiotics (tetracycline, sulfathiazole, ampicillin) was performed with immobilized bacterial cells containing the glutathione S-transferases (GSTs). Antibiotics in animal feed contaminated wastewater usually inhibit the growth of microorganisms that treat the wastewater, so a bio-friendly treatment method is required. Therefore, we have shown that the inhibitory effects of antibiotics on bacteria were reduced by microorganisms containing detoxifying enzyme GSTs by using a cell immobilizing method in a bioreactor. The initial concentrations of tetracycline, sulfathiazole and ampicillin were 100 mg/L, 100 mg/L and 50 mg/L respectively, which are typical of the range detected in pig feed in Korea. In the results, we observed the removal efficiency of tetracycline to be almost 70% with Staphylococcus epidermidis in the bioreactor, suggesting that this method of antibiotic removal is worthy of further study.

► The removal of the antibiotics could be achieved by immobilized cells involved detoxifying enzyme GSTs.
► Microorganisms immobilized on alginate micro-spheres were introduced to poultry wastewater treatment plants.
► Cell cultures on bio-carriers demonstrated a high capability of producing a large amount of enzyme.
► The good performance on reducing antibiotics’ strong concentration in pig feed was showed.