CAJ | 학술논문

从生产乙草胺的农药厂排污口污泥中分离到一株乙草胺降解菌，命名为DC-6。根据形态特征、生理生化特性以及16S rDNA系统发育分析，初步鉴定其为鞘氨醇单胞菌属（ Sphingomonas sp．）。该菌能够降解甲草胺、乙草胺和丁草胺，而对于异丙甲草胺、丙草胺和异丙草胺却没有任何降解效果，48 h对丁草胺、乙草胺和甲草胺的降解率分别为76．7％、93．6％和98．6％，对甲草胺的降解效率最高，而对丁草胺的降解效率最低，表明侧链烷基长短影响着该类除草剂的降解速率，随着侧链基团碳原子的增加以及支链的增多降解效率呈下降的趋势。通过气相色谱-质谱鉴定了该菌降解乙草胺的代谢产物并分析了乙草胺的代谢途径，发现乙草胺首先N-脱烷基形成2-氯-N-（2-乙基-6-甲基苯基）乙酰胺（CMEPA），然后水解生成苯胺衍生物2-乙基-6-甲基苯胺（ MEA），MEA能够进一步完全降解。但苯胺类化合物降解途径中的关键酶苯胺双加氧酶没有参与MEA降解代谢，表明菌株DC-6对MEA的降解不同于已报道苯胺降解途径。
종생산을초알적농약엄배오구오니중분리도일주을초알강해균，명명위DC-6。근거형태특정、생리생화특성이급16S rDNA계통발육분석，초보감정기위초안순단포균속（ Sphingomonas sp．）。해균능구강해갑초알、을초알화정초알，이대우이병갑초알、병초알화이병초알각몰유임하강해효과，48 h대정초알、을초알화갑초알적강해솔분별위76．7％、93．6％화98．6％，대갑초알적강해효솔최고，이대정초알적강해효솔최저，표명측련완기장단영향착해류제초제적강해속솔，수착측련기단탄원자적증가이급지련적증다강해효솔정하강적추세。통과기상색보-질보감정료해균강해을초알적대사산물병분석료을초알적대사도경，발현을초알수선N-탈완기형성2-록-N-（2-을기-6-갑기분기）을선알（CMEPA），연후수해생성분알연생물2-을기-6-갑기분알（ MEA），MEA능구진일보완전강해。단분알류화합물강해도경중적관건매분알쌍가양매몰유삼여MEA강해대사，표명균주DC-6대MEA적강해불동우이보도분알강해도경。
An acetochlor herbicides-degrading strain, designated as DC-6, was isolated from activated sludge of the wastewater outfall of a factory from Kunshan City. According to the morphological, physiological and biochemical characteristics and the phylogenetic analysis of 16S rDNA sequence, the strain was identified preliminarily as Sphingomonas sp.. Strain DC-6 could degrade alachlor,acetochlor and butachlor, but could not degrade metolachlor, pretilachlor and propisochlor. Within 48 hours of incubation, about 76. 7% of butachlor, 93. 6% of acetochlor and 98?6% of alachlor were degraded by strain DC-6, respectively. The degradation rates followed the order of alachlor >acetochlor > butachlor. These results indicated that the factors influencing the biodegradability of these herbicides were the length and complicated of amide nitrogen?s alkoxymethyl:the longer and more complicated the alkyl was, the slower the degradation efficiencies occurred. The pathway of acetochlor degradation was elucidated based on the results of metabolites identification by GC-MS. Acetochlor was firstly degraded to 2-chloro-N-( 2-methyl-6-ethyl ) phenyl-acetamide (CMEPA) by N-dealkylation, and then it subsequently transformed to 2-methyl-6-ethylaniline (MEA). MEA was further completely degraded via unknown metabolites. However, aniline dioxygenase, which was the key enzyme in the degradation of aniline and aniline derivatives, did not involve in the degradation of MEA. This indicated that the degradation of MEA by strain DC-6 was different from the reported aniline degradation pathway.