克百威降解菌CYW-44的分离及其酶促降解研究

为了有效治理克百威农药污染,以克百威为唯一碳源,利用富集培养的方法从农药厂活性污泥中分离到一株克百威降解菌CYW-44,经生理生化、16S rDNA序列分析及API 50CHB鉴定试剂条分析,将菌株鉴定为枯草芽孢杆菌(Bacillus subtilis)。该菌在营养培养基中培养5 d时对100 mg.L-1的克百威降解率为97.72%,6 d能够完全降解克百威。通过液相色谱(HPLC)法检测,发现在降解过程中,克百威降解产物呋喃酚及其他代谢产物不产生累积;研究证实该菌株能分泌胞外降解酶和胞内降解酶高效降解克百威,对克百威的降解率分别达到99.1%和82.63%;通过SDS-PAGE验证了克百威对菌株降解酶活性的诱导作用。

Isolation of A Novel Carbofuran-degrading Bacterium and Its Enzymatic Degradation of Carbofuran

As a carbofuran-degrading bacterium, the strain CYW-44 was isolated from activated sludge samples of the agri-chemistry factory through the batch culture enrichment technique. It was selected due to its rapid growth on carbofuran medium. Based on morphological, physiological and biochemical tests, 16S rDNA analysis and API strip test, the strain was identified as Bacillus subtilis. Carbofuran of 100 mg·L~(-1) concentration was degraded by the bacterium up to 97.72% within five days, and no carbofuran was detected in the sixth day. HPLC analysis results demonstrated that there was no accumulation of carbofuran phenol and the other metabolic intermediate during the degradation of carbofuran. Preliminary mechanism of degradation was investigated. Both ectoenzyme and endoenzyme of strain CYW-44 played significant roles during carbofuran degradation. SDS-PAGE analysis showed that a new protein band was found when strain CYW-44 growed on the carbofuran medium. It indicated that degradation activities of some enzymes could be induced by carbofuran.