School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou, 510275, China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China.
Chemosphere. 2021 Jul;274:129929. doi: 10.1016/j.chemosphere.2021.129929. Epub 2021 Feb 15.
This research investigated the biodegradation kinetics, pathways and ecological risk of hexabromocyclododecane (HBCD) by a novel bacterium Citrobacter sp. Y3. Results showed the biodegradation followed a first-order model. The specific degradation rate constant of HBCD were obviously higher in batch experiments with combined carbon sources (k: 0.156-0.290 d) than those using HBCD as the sole carbon source (k: 0.055 d). Correspondingly, the degradation half-life became much shorter (T: 2.39-4.44 d vs T: 13.7 d). HBCD could be degraded through dehydrobromination and dehalohydroxylation, of which six possible degradation products were detected. To evaluate the ecological risk of HBCD biodegradation products, acute toxicity tests were assessed for the first time. The acute toxicity decreased slowly during treatment for 3-5 d and then decreased sharply. In general, treatment by Strain Y3 is not only a biodegradation process but also a detoxification process, thus it shows potential for bioremediation of HBCD contaminated sites.
本研究通过一株新型细菌柠檬酸杆菌（Citrobacter sp. Y3）对六溴环十二烷（HBCD）的生物降解动力学、途径和生态风险进行了研究。结果表明，HBCD 的生物降解符合一级模型。在使用复合碳源的批实验中（k：0.156-0.290 d），HBCD 的特定降解速率常数明显高于仅使用 HBCD 作为唯一碳源时（k：0.055 d）。相应地，降解半衰期变得更短（T：2.39-4.44 d 与 T：13.7 d）。HBCD 可以通过脱溴和脱卤羟基化进行降解，其中检测到六个可能的降解产物。为了评估 HBCD 生物降解产物的生态风险，首次进行了急性毒性测试。在 3-5 d 的处理过程中，急性毒性缓慢下降，然后急剧下降。总的来说，菌株 Y3 的处理不仅是一个生物降解过程，也是一个解毒过程，因此它显示出在 HBCD 污染场地进行生物修复的潜力。
