维生素B_(12)对脱氯功能蓝藻降解2,4,4'-三氯联苯的促进作用研究  

Promotion Effects of Vitamin B_(12) on the Degradation of 2,4,4'-Trichlorobiphenyl by Nostoc PD-2

作　　者：刘嘉裕[1] 肖文丰[1] 鲁莉萍[1] 张杭君[1] 

机构地区：[1]杭州师范大学生命与环境科学学院,杭州310036

出　　处：《环境科学》2014年第8期3162-3168,共7页Environmental Science

基　　金：国家自然科学基金项目(21077030);杭州师范大学优秀中青年教师支持计划项目(JTAS2011-01-012);杭州市"131"人才计划支持项目;杭州师范大学学生科研立项项目(1283XXM09);杭州师范大学本科生创新提升工程立项项目(CX2013078)

摘　　要：多氯联苯(polychlorinated biphenyls,PCBs)是环境中典型的持久性氯代有机污染物.PCBs污染的生物修复问题是当前环境科学领域的热点.以维生素B12(VB12)为实验材料,应用无氯培养体系,研究了VB12对脱氯功能蓝藻Nostoc PD-2脱氯降解2,4,4'-三氯联苯(PCB28)和降解过程基因表达的影响.结果表明,添加不同浓度的VB12能够促进Nostoc PD-2对PCB28的降解,添加浓度分别为10、100和1000μg·L-1的维生素B12时,与未添加VB12组相比,其7 d脱氯百分比分别提高了11.0%、19.7%和21.9%;添加10μg·L-1和100μg·L-1维生素B12条件下,PCB28的降解半衰期从5.53 d缩短至3.08 d.添加维生素B12后,细胞色素b6f复合体铁硫蛋白基因和双加氧酶基因的表达量均与PCB28的降解效果呈现显著相关性,铁硫蛋白基因表达量与PCB28降解效果的相关性更高.上述结果表明添加VB12能够有效促进脱氯功能藻种PD-2对PCB28的降解,并在基因水平上影响功能藻种的降解活性,这能够为开发高效生物降解PCBs的技术和脱氯功能藻种降解PCBs的机制提供科学依据.Polychlorinated biphenyls are typical persistent chlorinated organic compounds in the environment. Bioremediation of PCBcontaminated environment has become one of the hot issues. In this study,vitamin B12（VB12） and chlorine-free culture medium were applied to study the effects of VB12 on the degradation of 2,4,4＇-trichlorobiphenyl（PCB28） by Nostoc PD-2 and the gene expression during the PCB-degradation process. Results showed that addition of different concentrations of vitamin B12 could improve the PCBbiodegradation rates by Nostoc PD-2. Compared with the control group,the 7-day degradation rate in 10 μg·L^-1,100 μg·L^-1,and1 000 μg·L^-1 VB12-treated groups increased by 11. 0%,19. 7%,and 21. 9%,respectively. The degradation half-time decreased from5. 53 days（treated with 10 μg·L^-1 VB12） to 3.08 days（treated with 100 μg·L^-1 VB12）. The expression of cytochrome b6 f complex iron-sulfur protein gene and dioxygenase gene showed significant correlation with PCB28-degradation by Nostoc PD-2. While the expression of iron-sulfur protein gene showed more significant correlation with PCB28-degradation. Results in this study indicated that adding VB12 could promote PCB28-degradation by Nostoc PD-2. Moreover,VB12 addition improved the PCB-degradation activity of Nostoc PD-2 at the gene level. The above conclusions could provide a new choice for developing efficient bioremediation technology for PCB-contaminated environment and a new insight into the PCB-biodegradation mechanism by Nostoc PD-2.

关 键 词：多氯联苯 脱氯 生物修复 维生素B12 NOSTOC PD-2 

分 类 号：X131[环境科学与工程—环境科学] X171.5