Biodegradation of decabromodiphenyl ether by intracellular enzyme obtained from Pseudomonas aeruginosa

The degradation characteristics of decabromodiphenyl ether(BDE-209) by crude enzyme from Pseudomonas aeruginosa were investigated.The results revealed that the degradation efficiency of the intracellular enzyme excreted from this bacterial strain reached 69.22% after incubation with 1 mg·L-1 BDE-209 for 12 h.Temperature,pH,enzyme concentration and BDE-209 concentration all influenced the ability of crude enzyme to degrade BDE-209.When the BDE-209 concentration was 1 mg·L-1,the optimal condition for enzymatic degradation was temperature 30℃ and pH 7.5,and the degradation rate increased with increasing enzyme concentration.The degradation process of BDE-209 by intracellular enzyme of the strain conformed to the first-order kinetic model.The highest reaction rate was achieved when the initial concentration of BDE-209 was 1 mg·L-1 and the half-life of this substrate was 6.9 h.In addition,the biodegradation of BDE-209 can be well described by enzymatic reaction of high concentration substrate inhibition,with a maximum substrate utilization rate of 0.133 mg·(L·h)-1,a Michaelis-Menten constant of 0.642 mg·L-1,and an inhibitory constant of 1.558 mg·L-1,respectively.