Cd(Ⅱ)对多环芳烃降解菌Bacillus sp.P1产酶及酶促降解过程影响研究

Effects of Cd(Ⅱ) on Enzyme Productions of PAHs-biodegrading Bacillus sp.P1 and the Characteristics of Enzymatic Degradation

为研究重金属对多环芳烃降解过程中降解菌产酶及酶促降解过程的影响,本实验以菲和Cd(II)为代表物质,探究了多环芳烃降解菌Bacillus sp.P1降解菲的过程中,不同浓度Cd(II)对Bacillus sp.P1产生的蛋白浓度、组成及降解菲程中的关键开环酶邻苯二酚2,3-双加氧酶酶活以及其对菲酶促降解率的影响.结果表明,Cd(II)对Bacillus sp.P1的产酶过程和酶促降解过程均有抑制作用:当Cd(II)浓度由0mg/L增加到150mg/L时,蛋白分子条带的表达量明显减少,胞外蛋白及胞内蛋白条带总浓度分别由8.37×106,1.54×107降至5.49×106,6.01×106(Gelpro软件分析值);且当体系中Cd(II)浓度由0mg/L增加到300mg/L时,胞外和胞内酶中的邻苯二酚2,3-双加氧酶酶活分别由266.96,886.30U/mg下降至38.93,290.26U/mg;且胞外酶和胞内酶对菲的酶促降解率分别由79.86%,87.96%下降至64.59%,74.83%.以上实验结果共同表明Cd(II)对降解菌Bacillus sp.P1的产酶过程及酶促降解过程的影响是其影响多环芳烃降解菌降解能力的重要机制.

To elucidate the effect of heavy metals on enzymes production and the characteristics of enzymatic degradation in the process of biodegradation of polycyclic aromatic hydrocarbons （PAHs） by Bacillus sp.P1,enzyme variations （the content and composition of proteinase,the activities of catechol 2,3-dioxygenase in crude enzymes and enzymatic degradation ability） in the process of phenanthrene degradation were investigated in the presence of Cd（Ⅱ）.The results showed that Cd （Ⅱ） would inhibit enzyme productions and enzymatic degradation.As Cd（Ⅱ） increased from 0 to 150 mg/L,the amount of extracellular and intracellular proteinase （absolute integrated optical density analyzed by Gelpro） decreased from 8.37 × 106,1.54× 107 to 5.49× 106,6.01 × 106,respectively.As Cd（Ⅱ） increased from 0 to 300 mg/L,the activities of catechol 2,3-dioxygenase in extracellular enzymes （EE） and intracellular enzymes （IE） decreased from 266.96 to 38.93 U/mg,886.30 to 290.26 U/mg,respectively.The degradation rates of Phenanthrene （PHE） byEE and IE decreased from 79.86％ to 64.59％,87.96％ to 74.83％,respectively.These results suggest that Cd （Ⅱ） can cause enzyme variation,thus affecting the phenanthrene biodegradation by Bacillus sp.P1.