| The characteristics of pyrene degradation and Cd adsorption by Stenotrophomonas maltophilia were investigated and the mechanisms of repairing the single pollution of pyrene, Cd and the co-contamination of these two by the strain were preliminarily studied. The results showed that the degradation efficiency of pyrene firstly ascended and then descended with the increase of pyrene concentration. The highest degradation ratio of 65.74% was reached when pyrene concentration came up to 2 mg·L-1 after 4 d. Under the circumstance of pyrene-Cd combined contamination, low concentration of Cd（less than 0.5 mg·L-1） played no significant influence on the degradation of pyrene, while high concentrations of Cd（5 mg·L-1 and 10 mg·L-1） inhibited pyrene degradation and was detrimental to Cd removal. The SEM observation indicated that S. maltophilia could maintain integral shape in either pollution system, while the combined pyrene-Cd exhibited the worst toxicity on the cell since it caused local depression on cell surface and some cells busted. FTIR analysis showed that with increasing time as well as the degradation/adsorption of pyrene - Cd some changes were made on the cell surface groups. |
