| 维生素B12对脱氯功能蓝藻降解2,4,4’-三氯联苯的促进作用研究 |
| 摘要点击 1810 全文点击 969 投稿时间：2013-11-27 修订日期：2014-02-18 |
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| 中文关键词 多氯联苯 脱氯 生物修复 维生素B12 NostocPD-2 |
| 英文关键词 polychlorinated biphenyls dechlorination bioremediation vitamin B12 Nostoc PD-2 |
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| 中文摘要 |
| 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1000 μg·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10 μg·L-1 和100 μg·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. |
| 英文摘要 |
| Polychlorinated biphenyls are typical persistent chlorinated organic compounds in the environment. Bioremediation of PCB-contaminated 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 PCB-biodegradation rates by Nostoc PD-2. Compared with the control group, the 7-day degradation rate in 10 μg·L-1, 100 μg·L-1, and 1000 μg·L-1 VB12-treated groups increased by 11.0%, 19.7%, and 21.9%, respectively. The degradation half-time decreased from 5.53 days (treated with 10 μg·L-1 VB12) to 3.08 days (treated with 100 μg·L-1 VB12). The expression of cytochrome b6f 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. |
