附着剑菌对三氯联苯的吸附及降解机制研究

实验研究附着剑菌(Ensifer adhaerens.R2)对持久性有机污染物三氯联苯(2,4,4′-TCB,PCB28)的去除机制,探究菌株对2,4,4′-TCB的生物吸附和生物降解作用,以及其随时间、pH值、温度、菌体密度、金属离子(Ca2+、Mg2+)的变化.灭活菌体对PCBs的去除机制为生物吸附,吸附率在2h基本达到平衡,为85.97%;活体菌株可以通过生物吸附及生物降解作用去除2,4,4′-TCB,在本次实验周期内主要以吸附作用为主,2h吸附率为60.59%,明显高于降解率的12.90%.单因素条件下,pH值为6.0、35℃、OD为0.8、添加1mol/L的Ca2+、Mg2+处理可使活菌对2,4,4′-TCB的吸附达到最优;pH值为7.5,30℃,添加0.05mol/L的Ca2+、Mg2+处理可使活菌对2,4,4′-TCB的降解达到最优.

Biosorption and biodegradation mechanisms of trichlorobiphenyl by Ensifer adhaerens

This study was aimed to investigate the bio-dissipation mechanisms of 2,4,4′-trichlorobiphenyl (2,4,4′-TCB, PCB28) by Ensifer adhaerens, and explore the variation of the biosorption and biodegradation with the changes of time, pH, temperature, optical density, metal ions (Ca2+、Mg2+). The removal mechanism of 2,4,4′-TCB by dead E. adhaerens was biosorption, the adsorption efficiency reached a plateau after 2h incubation,which was 85.97%. Both biosorption and biodegradation contributed to the removal of 2,4,4′-TCB by live E. adhaerens in water, and in this experimental period biosorption was dominated. The adsorption efficiency and degradation efficiency were 60.59% and 12.90% respectively. The highest adsorption efficiency of live strain was occurring at pH of 6.0, temperature of 35℃, OD of 0.8, cell pretreated with 1mol/L metal ion. The optimal degradation efficient of live strain was under the condition of 7.5pH, 30℃, biomass pretreated with 0.05mol/L metal ion.