Biodegradation of 4-aminobenzenesulfonate by a novel Pannonibacter sp. W1 isolated from activated sludge.

4-Aminobenzenesulfonate (4-ABS) is a representative intermediate of some sulfonated azo dyes. A novel Pannonibacter sp. strain W1 capable of degrading 4-ABS as sole carbon as well as energy, nitrogen and sulfur source was isolated and identified from the activated sludge of a municipal wastewater treatment plant. Strain W1 was able to completely degrade 4-ABS with initial concentrations of 200-2500 mg L(-1) within 40 h. Haldane inhibition model was used to fit the special degradation rate at different initial concentrations, and the parameters micro(max), K(s) and K(i) were determined to be 227.977 mg (gh)(-1), 84.306 mg L(-1) and 1270.675 mg L(-1), respectively. Elements N and S of 4-ABS were released in respective forms of ammonia and sulfate while degrading 4-ABS by strain W1, accounting for 77.6% and 92.2% of theoretical values, respectively. Relatively low recoveries of dissolved N and S were probably owing to the fact that part of the released ammonia and sulfate were utilized by strain W1 for cell growth. It was found that the reduction of total organic carbon (TOC) was proportional to the degradation of 4-ABS and 84.4% TOC removal rate, corresponding to a 4-ABS degradation rate of 94.7%, was achieved at the end of the test. Additionally, HPLC and UV analyses indicated that there were no other aromatic intermediates detectable, suggesting the achievement of a complete mineralization of 4-ABS with strain W1.