Jin-Song Zhang

Kinetics of 4-aminobensenesulphonate (4-ABS) degradation by Pannonibacter sp. W1 under aerobic condition was studied. At medium and low initial concentration (50-1000 mg/L), the 4-ABS could be degraded almost completely in 14 h,and the degradation reaction conformed to one order kinetics. At high initial concentration (1 200-2500 mg/L), up to 90% degradation rate could be achieved in 32 h, and it conformed to zero order kinetics in earlier period of degradation and one order kinetics in later period of degradation. Haldane inhibition model was used to fit the special degradation rate at different initial concentration, and the parameters micro(max), K(s) and K(i) were determined to be 227.977 mg/(g x h), 84.306 mg/L and 1270.675 mg/L, respectively. UV spectrum and HPLC detection indicated that no other aromatic intermediates were accumulated during the 4-ABS degradation. The degradation of other substituted benzenes by strain W1 were detected, and the metabolic pathway of 4-ABS degradation was proposed.

A 4-aminobenzenesulphonate-degrading strain W1 was isolated from the activated sludge of Dalian municipal wastewater treatment plant. Strain W1 was able to utilize 4-ABS as sole carbon and energy source under aerobic condition. It was identified as Pannonibacter sp. according to its morphological, physiological and biochemical characteristics and the analysis of its 16S rDNA gene. The optimum conditions for 4-ABS biodegradation in the shaking flasks were 10% inoculum, 30 degrees C, pH 7.0 and were rotated at speed 150 r/min, respectively. Strain W1 could keep high degrading ability even in the presence of extra carbon source. Release of ammonia and sulfate were around 77.6% and 91.5% of theoretic concentration according to 4-ABS degradation, for 4-ABS could serve as the nitrogen and sulfur source. Strain W1 showed efficient biodegradability even at 2,500 mg/L, and 90% 4-ABS removal was achieved in 32 h. The 84.4% TOC removal was achieved after 94.7% consumption of 4-ABS, and no aromatic intermediates were detected, referring the complete mineralization of 4-ABS by strain W1.