固定化铜绿假单胞菌GF31对氯氰菊酯降解的强化作用

Bioaugmentation strategy to enhance cypermethrin degradation by immobilized Pseudomonas aeruginosa GF31

研究了沸石固定化铜绿假单胞菌GF31的氯氰菊酯降解特性及强化修复效果。综合考虑氯氰菊酯特性及其传质等因素,选择沸石为载体进行固定化,电镜扫描结果显示,菌株GF31能较好地生长于沸石载体孔隙中。固定化后菌株GF31的去除率和比降解速率提高,6d对100mg·L-1氯氰菊酯的去除率由37%提高至61.4%,游离细胞和固定化细胞对于300mg·L-1的氯氰菊酯的平均比降解速率分别为487和917mg·[L·d·(g细胞干重)]-1。固定化细胞对pH和高浓度氯氰菊酯的耐受性显著增强,在pH 10或者菊酯浓度为800mg·L-1时仍能保持一定的降解活力。投加固定化细胞对实际土壤进行生物强化修复,其降解过程可用一级动力学方程来描述。与自然降解相比,氯氰菊酯的半衰期t1/2由34.3d缩短至8.02d,显示出固定化细胞良好的强化修复效果。

The immobilization of Pseudomonas aeruginosa GF31 and its enhancement of biodegradation of cypermethrin were investigated. Zeolite was chosen as a suitable support for the immobilization by taking into account the properties of cypermethrin and mass transfer in the bioremediation. Scanning electron microscope （SEM） images demonstrated that strain GF31 grew well in the pore of the zeolite. After immobilization, cypermethrin removal efficiency was improved significantly from 37% to 61.4% at initial cypermethrin concentration of 100 mg . L-1 in 6 d. The specific degradation rate of free ceils and immobilized cells were 487 and 917 mg. [L . d . （g dry biomass）]-1 respectively, at 300 mg . L-1 cypermethrin. It was also found that the immobilized cells exhibited higher tolerance to pH and cypermethrin concentration, keeping its activities even at pH 10 or higher cypermethrin concentration up to 800 mg . L-1. The results of actual soil remediation by the immobilized cells showed that cypermethrin degradation could be well described by a first-order reaction rate equation. As compared to natural degradation,cypermethrin half life （t1/2） was shortened from 34.3 d to 8.02 d, which illustrated a good result of bioaugmented remediation by the immobilized Pseudomonas aeruginosa GF31.