Degradation of antibiotics (tetracycline, sulfathiazole, ampicillin) using enzymes of glutathion S-transferase

Swine wastewater is not easily treated in biological wastewater treatment plants. One reason is that some antibiotics are not easily degradable in a normal treatment system and inhibit the biological organisms in the treatment system. Specifically, tetracycline, sulfathiazole, and ampicillin are representative antibiotics found in poultry wastewater. To degrade these refractory and impediment antibiotics more easily, a special method is needed, such as an enzyme method. This research used a special enzyme in an experiment that tested feasibility with an enzyme assay of biological treatment in vitro. The Glutathion S- Transferases ( GSTs) are a family of proteins that catalyze the conjugation of reduced glutathione with a variety of hydrophobic chemicals containing electrophilic centers. Using GSTs, these major antibiotics were transformed into components that were non-toxic to the microorganisms that treat manure wastewater. The initial concentration of tetracycline, sulfathiazole, and ampicillin were 100 mg/L, 100 mg/L, and 50 mg/L, respectively, and the concentration of pig feed was the same as usual. The GSTs have made the effect of biotransformation of antibiotics as their mode. They were 60 - 70% transformed by GSTs at the end of the degradation reaction. This lowered their inhibitory strength against microorganisms.