[Kinetics and mechanism of 4-aminobenzenesulphonate biodegradation]

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.