摘要
探讨了镉(Cd)对铜绿假单胞菌(P.aeruginosa)SH1处理壬基酚(NP)的影响.结果表明,P.aeruginosa SH1的生物量随着Cd2+浓度的增大有明显的降低,10 mg·L^(-1)Cd2+存在时,菌株在24 h的生物量下降27.1%;Cd2+的加入对于菌体吸附NP有较大影响.对于活菌,低浓度Cd2+(0.5 mg·L^(-1))能够促进P.aeruginosa SH1吸附NP,而高浓度Cd2+(≥5 mg·L^(-1))的加入起抑制作用.对于失活菌体,低浓度Cd2+的加入对于菌体吸附NP无显著性影响,而高浓度的Cd2+能够促进吸附作用;降解实验结果表明,胞内酶的降解速率要远远大于菌体.不同浓度的Cd2+对菌体和胞内酶降解NP有着不同的影响.当体系中存在高浓度Cd2+时,胞内酶和菌体降解NP均受到抑制,胞内酶受到的抑制作用更显著.低浓度的Cd2+对菌体降解NP有促进作用,而对胞内酶降解NP无显著性影响;胞内酶对NP的降解过程符合一级动力学反应模型,Cd2+浓度为0.5 mg·L^(-1)时降解速率最快,半衰期为5.5 h,而菌体降解NP则不能很好地通过一级动力学模型进行拟合.
The influence of Cd on the degradation of nonylphenol（ NP） by P. aeruginosa SH1 was investigated in this study. The investigation revealed that biomass of the strain was significantly declined with the increase of Cd2 ＋concentration. The biomass was declined by 27. 1% in the presence of 10 mg·L^-1Cd2 ＋after 24 h. The addition of Cd2 ＋had a great influence on adsorption of NP by the strain. As for the effect of living stain,adsorption by P. aeruginosa SH1 cells was stimulated at low concentrations of Cd2 ＋（ 0. 5mg·L^-1）,while inhibited at higher levels（ ≥5 mg·L^-1）. As for inactivation of microbes,adsorption by cells was stimulated at higher concentrations,but was only slightly influenced at low levels. The results showed that the intracellular enzymes had much greater degradation rate than the living cells. Different concentrations of Cd2 ＋had different effects on bacteria and intracellular enzyme degradation of NP separately. The degradation efficiency when using intracellular enzymes and bacteria was inhibited at higher levels of Cd2 ＋and the intracellular enzyme inhibition was more significant. Degradation by cells was stimulated at low concentrations of Cd2 ＋,but no significant impact was found on that by intracellular enzymes. The degradation process of NP by intracellular enzymes of the strain conformed to the first-order kinetic model. The highest reaction rate was achieved when the concentrations of Cd2 ＋was 0. 5mg·L^-1and the half-life of this substrate was 5. 5 h. However,the degradation process of NP by the strain did not conform to the firstorder kinetic model.
作者
史广宇
程媛媛
施维林
SHI Guang-yu CHENG Yuan-yuan SHI Wei-lin(College of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2017年第1期294-300,共7页
Environmental Science
基金
国家自然科学基金项目(3157051)
江苏省自然科学基金青年基金项目(BK20150287)
苏州科技学院青年基金项目(XKQ201415)
关键词
铜绿假单胞菌
壬基酚
镉
降解
动力学
Pseudomonas aeruginosa
nonylphenol
Cd
degradation
kinetics
