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Studies on the enzymatic characteristics of methar monooxygenase and its trichloroethylene degrading activity

Methar单加氧酶的酶学特性及其三氯乙烯降解活性研究

基本信息

批准号：
04650497
负责人：
FURUKAWA Kenji
金额：
$ 1.28万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

We have showed that the methane utilizing bacteria widely inhabit the natural water and soil environments. There existed big differences in the trichloroethylene degrading activities of our prepared methane utilizing enrichment cultures. Among these enrichment cultures, the enrichment culture prepared from the ground water polluted with trichloroethylene showed the highest trichloroethylene degrading activity. Effective trichloroethylene degradation was obtained under the cultural condition with low methane partial pressure. Treatment temperature gave much influence on its degrading activity. Enrichment culture cultivated on methanolic medium showed a low trichloroethylene degrading activity. The responsible enzyme for trichloroethylene degradation was proved to be a methane monooxygenase from the inhibition experiments using acetylene. The enrichment culture degraded 30 mg/L of trichloroethylene effectively. The enrichment culture could not degrade tetrachloroethylene and 1,1,1-trichloroethane, but could degrade chloroform. Trichloroethylene degrading activity of the enrichment culture decreased during the repeated contacts with trichloroethylene.Isolation of methane utilizing bacterium which can degrade trichloroethylene was failed owing to its strict growth condition.Methane monooxygenase belonging to the enrichment culture was studied enzymatically. Methane monooxygenase activity was detected in the soluble (cytoplasmic) fraction, but was not detected in particulate (membrane) fraction.

研究表明，利用甲烷的细菌广泛存在于自然水体和土壤环境中。利用富集培养基制备的甲烷对三氯乙烯的降解活性存在较大差异。在这些富集培养物中，三氯乙烯污染地下水制备的富集培养物对三氯乙烯的降解活性最高。在甲烷分压较低的条件下，对三氯乙烯有较好的降解效果。处理温度对其降解活性影响较大。在甲醇培养基上培养的富集菌对三氯乙烯的降解活性较低。通过对乙炔的抑制实验，证实了三氯乙烯降解的主要酶是甲烷单加氧酶。富集培养物可有效降解30 mg/L的三氯乙烯。富集培养不能降解四氯乙烯和1,1,1-三氯乙烷，但能降解氯仿。在与三氯乙烯的反复接触过程中，富集培养物的三氯乙烯降解活性下降。利用能降解三氯乙烯的细菌分离甲烷由于其生长条件严格而失败。对富菌甲烷单加氧酶进行了酶学研究。在可溶性（细胞质）部分检测到甲烷单加氧酶活性，但在颗粒（膜）部分未检测到。