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BIODEGRADATION PROCESSES OF CHLORINATED ORGANICS UNDER ANAEROBIC ENVIRONMENTS

厌氧环境下氯化有机物的生物降解过程

基本信息

批准号：
08455242
负责人：
TANAKA Shuzo
金额：
$ 3.39万
依托单位：
MEISEI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08455242/
关键词：
reductive dechlorination methane producing bacteria sulfate reducing bacteria chlorophenol nitrate reduction electron donor 脱窒細菌真正細菌 pH 温度

项目摘要

Under anaerobic environments anaerobic bacteria reductively dechlorinated 2,4,6-trichlorophenol (2,4,6TCP) and decomposed it into 4-chlorophenol (4CP) and 2-chlorophenol (2CP) via 2,4-dichlorophenol (2,4DCP). About 95% of initial 2,4,6TCP were converted into 4CP and the remaining 5% were into 2CP. Although 2CP was further dechlorinated and converted into phenol, 4CP was not degraded and accumulated in the reactor.By investigating the involvement of methane producing bacteria (MPB) and sulfate reducing bacteria (SRB) in the reductive dechlorination of 2,4,6TCP, it was made clear that the dechlorination of 2,4,6TCP into 4CP and 2CP was conducted by SRB but the further dechlorination of 2CP was done by MPB. The dechlorination activity of MPB, however, was affected by the sulfate reduction by SRB, and it was greatly decreased when 50mg/L sulfate were reduced into hydrogen sulfide (HィイD22ィエD2S) and completely ceased at 100mg/L sulfate.Additionally, studied was the relation between 2CP dechlorination and nitrate reduction (denitrification) in the presence of nitrate under anaerobic condition. When acetate is available as electron donor, 2CP was reductively dechlorinated and converted into phenol independent of the presence of nitrate. Also, when the MPB activity was inhibited by chloroform or BESA in the presence of nitrate, nitrate was reduced into nitrogen gas but 2CP was not decomposed at all. This means that MPB are primary bacteria associated with the 2CP dechlorination. On the other hand, when no electron donor is present, 2CP was not decomposed without nitrate but oxidatively degraded by coupling with nitrate reduction in the presence of nitrate. It was shown that 2CP could be degraded reductively in the presence of electron donor or oxidatively by coupling with nitrate reduction without electron donor.

在厌氧条件下，厌氧细菌对2，4，6-三氯苯酚（2，4，6 TCP）进行还原脱氯，并通过2，4-二氯苯酚（2，4DCP）分解为4-氯苯酚（4CP）和2-氯苯酚（2CP）。约95%的初始2，4，6 TCP转化为4CP，其余5%转化为2CP。通过研究产甲烷菌（MPB）和硫酸盐还原菌（SRB）对2，4，6 TCP还原脱氯的影响，发现2，4，6 TCP的还原脱氯主要是由产甲烷菌（MPB）和硫酸盐还原菌（SRB）共同参与的。6 TCP在SRB作用下转化为4CP和2CP，而2CP的进一步脱氯作用由MPB完成。MPB的脱氯活性受硫酸盐还原菌还原硫酸盐的影响，当硫酸盐还原浓度为50 mg/L时，MPB的脱氯活性大大降低，当硫酸盐还原浓度为100 mg/L时，MPB的脱氯活性完全停止。当乙酸盐作为电子供体时，2CP被还原脱氯并转化为苯酚，而不依赖于硝酸盐的存在。此外，当MPB活性被氯仿或BESA抑制在硝酸盐的存在下，硝酸盐被还原成氮气，但2CP在所有不分解。这意味着MPB是与2CP脱氯相关的主要细菌。另一方面，当不存在电子供体时，2CP在没有硝酸盐的情况下不分解，而是在硝酸盐的存在下通过与硝酸盐还原偶联而氧化降解。结果表明，2CP在有电子供体存在下可被还原降解，而在无电子供体的情况下，2CP可与硝酸盐还原反应耦合而被氧化降解。