壳聚糖固定化漆酶酶学性质及其催化氧化水中2，4-二氯酚的效能与途径  

Enzymatic properties and catalytic capacity of immobilized laccase on modified chitosan for 2,4-Dichlorophenol degradation

作　　者：王颖[1] 张笛[1] 茹加[2] 赵旭[3] 梁鹏[4] 

机构地区：[1]北京师范大学环境学院水环境模拟国家重点实验室,北京100875 [2]中国科学院计划财务局,北京100864 [3]中国科学院生态环境研究中心、环境水质学国家重点实验室,北京100085 [4]清华大学环境学院环境模拟与污染控制国家重点联合实验室,北京100083

出　　处：《环境化学》2013年第10期1901-1908,共8页Environmental Chemistry

基　　金：国家自然科学基金(21177013);国家重点基础研究计划(973)项目(2010CB429003);国家国际科技合作专项(2013DFR90290);环境模拟与污染控制国家重点联合实验室专项经费(13L03ESPC)资助

摘　　要：采用化学交联法制备了壳聚糖固定化漆酶,考察了固定化漆酶的酶学特性及其对2,4-二氯酚(2,4-DCP)的降解效能和降解途径.红外分析表明,壳聚糖表面的—NH2与戊二醛的—CHO反应发生交联,漆酶固定在了交联后的壳聚糖上.与游离漆酶相比,固定化漆酶对酸的适应能力、耐热性和贮存稳定性均有所提高,pH值在2.5—4.0范围内固定化漆酶活性较为稳定;最适温度从游离态的35℃上升至45℃;25℃下保存10 d,固定化漆酶活性仍为最初活性的88.70%.壳聚糖固定化漆酶可吸附-催化氧化水中的2,4-DCP,同时发生脱氯反应.利用8 g·L-1壳聚糖固定化漆酶降解2,4-DCP,反应16 h,50 mL初始浓度为32.83 mg·L-1的2,4-DCP去除率达54.80%.运用气相色谱-质谱联用技术分析了固定化漆酶催化氧化水中2,4-DCP的可溶性降解产物,在此基础上,提出了漆酶降解2,4-DCP的可能降解途径.Laccase was immobilized on chitosan by the chemical coupling method. The enzymatic properties of the immobilized laccase and its catalytic capacity for 2,4-dichlorophenol （2,4-DCP） degradation were systemically evaluated. The possible degradation pathway of 2,4-DCP was proposed. In comparison to free laccase, the immobilized enzyme had better acid adaptability, and thermal and storage stability. Higher activity was observed for immobilized laccase at a pH range of 2.5 to 4.0 and 45 ~C. After 10 days, 88.70% of the initial activity of immoblized laccase was retained. The immobilized lacease exhibited good catalytic capacity for removing 2,4-dichlorophnol from aqueous solutions. Simultaneously the concentration of chlorine ions in water increased. When the amount of immobilized laccase was 8 g. L- 1, removal efficiency of 2,4-DCP in water （solution volume： 50 mL, the initial concentration： 32.83 rag-L-1 ） reached 54.80% after 16 hours. A possible degradation pathway for 2,4-DCP in water was proposed based on the identification of major oxidation intermediates examined by Gas chromatogram-mass spectrum （GC-MS）. Random combination of phenoxy radical formed from the catalytic oxidation of 2,4-DCP by immobilized laccase formed some dimmers. These dimmers then form new radicals which could yield the trimer. Similarly, multimer was formed and then precipitate. On the other hand, dechlorination and ring-opening reaction during the catalytic oxidation of 2,4-DCP by immobilized laccase were found in our study. Because the main dissolved intermediates were hydroxy-malonic acid and 3-hydroxy cis, cis-Muconic acid, a possible catalytic degradation pathway for 2,4-DCP in water by immobilized laccase was proposed. That is, ortho-hydroxylation product of 2,4-DCP by catalytic oxidation of immobilized laccase was 4-Chloro catechol which can be further oxidized to have a ring- opening reaction to form 3-Chloro cis, cis-Muconic acid. Subsequently, 3-hydroxy cis, cis-Muconic acid was formed by the oxidative dechlorinat

关 键 词：固定化漆酶 酶学性质 2 4-二氯酚 降解途径 稳定性 

分 类 号：X13[环境科学与工程—环境科学]