过氧化物酶-辅酶NADH催化O_2/H_2O_2产生羟基自由基研究及其氯苯处理初探  

The Production of Hydroxyl Radical in HRP-NADH-H_2O_2/O_2 Systems and Its Application in Chlorobenzene Removal

作　　者：李海涛[1,2] 李玉平[2] 曹宏斌[2] 李鑫钢[1] 薛占强[3] 

机构地区：[1]天津大学化工学院,天津300072 [2]中国科学院过程工程研究所,绿色过程与工程重点实验室,北京100190 [3]鞍山钢铁股份有限公司化工总厂,辽宁鞍山114021

出　　处：《光谱学与光谱分析》2010年第11期3119-3123,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(20607023);国家高技术研究发展计划项目(2007AA06Z327)资助

摘　　要：利用光谱学和波谱学手段研究HRP-NADH-O2/H2O2体系中自由基生成机理及HRP状态的变化,并应用该酶体系对有机污染物氯苯进行初步处理研究。紫外可见光谱表明酶-辅酶体系在过氧化氢的氧化下,产生了强氧化性的化合物Ⅲ,说明可能产生羟基自由基。分别选用DMPO和POBN两种自由基捕获剂,通过电子自旋顺振(EPR)检测到HRP+NADH体系在O2和H2O2存在下产生超氧阴离子自由基(O2-·)和羟自由基(·OH)。在开始10min内过氧化物酶主要以化合物Ⅲ形式存在,随后转化为HRP,同时检测出较高浓度的·OH。O2存在条件下产生·OH浓度大约是单独H2O2存在条件下的4倍。超氧化物歧化酶(SODZn-Cu)在HRP+NADH+O2体系中能消除由NADH还原O2产生的O2-·从而抑制·OH生成。HRP+NADH体系相对于传统酶法处理能提高20%左右的酶活力,说明酶-辅酶体系能够提高酚类化合物的去除效率。实验条件下HRP+NADH+H2O2和HRP+NADH+H2O2+O2体系对于非酚类污染物氯苯的去除率分别到达了24.6%和48.2%,远高于传统酶法的1.42%,突破了传统酶处理只能处理酚类污染物的局限性。The mechanism of radical generation in HRP-NADH-O2/H2O2 systems and state-change of horseradish peroxidase（HRP）was investigated by using ESR and UV measurements,and the novel enzyme-coenzymatic systems were performed to degrade chlorobenzene as a non-phenolic persistent organic pollutants.The UV results showed that compound Ⅲ was produced from HRP oxidized by hydrogen peroxide with the catalysis of NADH,which would generate hydroxyl radical.The ESR results demonstrated the production of·OH and O2-·in enzyme-coenzymatic system in the presence of O2 or H2O2 with DMPO and POBN as spin-trappers,respectively.In HRP-NADH-H2O2 system,compound Ⅲ was the main state of HRP in the initial 10 min,and then converted to HRP with generating hydroxyl radical;and after the addition of oxygen,the production of hydroxyl radical was promoted rapidly,as 4 times as that of the system in absence of oxygen.The addition of SOD（Zn-Cu）decreased the production of hydroxyl radical significantly,resulting from that SOD eli minated O2 reduction to O2-·by NADH and then inhibited·OH formation.The results showed that NADH could improve by about 20% enzyme activity of HRP for phenol removal.The removal of chlorobenzene with HRP-NADH-H2O2 and HRP-NADH-H2O2-O2 systems reached 24.6% and 48.2%,respectively,which was much higher than that with traditional enzymatic system（1.42%）,showing apromising prospect in proposal of other non-phenol POPs in wastewater.

关 键 词：羟基自由基 辣根过氧化物酶 辅酶 电子自旋共振 废水处理 

分 类 号：O433.3[机械工程—光学工程]