Biodegradation of 4-aminobenzenesulfonate by Ralstonia sp. PBA and Hydrogenophaga sp. PBC isolated from textile wastewater treatment plant

Abstract

A co-culture consisting of Hydrogenophaga sp. PBC and Ralstonia sp. PBA, isolated from textile wastewater treatment plant could tolerate up to 100mM 4-aminobenzenesulfonate (4-ABS) and utilize it as sole carbon, nitrogen and sulfur source under aerobic condition. The biodegradation of 4-ABS resulted in the release of nitrogen and sulfur in the form of ammonium and sulfate respectively. Ninety-eight percent removal of chemical oxygen demand attributed to 20mM of 4-ABS in cell-free supernatant could be achieved after 118h. Effective biodegradation of 4-ABS occurred at pH ranging from 6 to 8. During batch culture with 4-ABS as sole carbon and nitrogen source, the ratio of strain PBA to PBC was dynamic and a critical concentration of strain PBA has to be reached in order to enable effective biodegradation of 4-ABS. Haldane inhibition model was used to fit the degradation rate at different initial concentrations and the parameters µmax, Ks and Ki were determined to be 0.13h-1, 1.3mM and 42mM respectively. HPLC analyses revealed traced accumulation of 4-sulfocatechol and at least four unidentified metabolites during biodegradation. This is the first study to report on the characterization of 4-ABS-degrading bacterial consortium that was isolated from textile wastewater treatment plant.