乙草胺降解菌Y-4的分离鉴定及降解特性研究

从长期经乙草胺污染的污泥中分离到一株能以乙草胺为唯一碳源和能源生长的菌株Y-4,通过生理生化实验和16S rDNA同源性序列分析,鉴定为申氏杆菌属（Shinella sp.）。采用室内培养方法,研究了Y-4对乙草胺的降解特性。结果表明,Y-4能有效地降解浓度为5～200 mg.L-1的乙草胺,在48 h内对50 mg.L-1乙草胺的降解率达到83.3%。菌株Y-4降解乙草胺的最适pH值为8.0,最适温度为30℃,其对丙草胺和丁草胺等农药也有良好的降解效果。

Isolation and Characterization of a Acetochlor-degrading Strain Y-4 and Its Degrading Characteristics

Acetochlor were widely used to weeding in agriculture and resulted in severely environmental pollution.Bioremediation is an effective and economic method to treat the environment that has been polluted by acetochlor.So researchers paid much attention in this area.In the present study,a bacterial strain Y-4 capable of utilizing acetochlor as sole carbon and energy sources was isolated from the sludge that have long been subjected to acetochlor pollution by enrichment method.The Y-4 cells were short rod,Gram nesative.The colonies on LB media were light yellow in color,circular,and smooth.Strain Y-4 was identified preliminarily as Shinella sp.based on its physiological and biochemical characters and the result of the 16S rDNA homologue sequence analysis.The Y-4 strain could effectively degrade acetochlor ranging of 5～200 mg·L-1.50 mg·L-1 acetochlor could be degraded at a rate of 83.3% by Y-4 strain in 48 h.The optimal initial pH value and temperature for acetochlor degradation by Y-4 was 8.0 and 30 ℃,respectively.Adding extra glucose or nitrogen source promoted the growth of strain Y-4,but influence the degradation of acetochlor slightly.The ion Mg2＋ could promote the strain to degrade acetochlor slightly,and Ni2＋,Co2＋,Hg2＋ could inhibit it when it was at low level.However,Zn2＋,Fe2＋ had no effect on the degradation of acetochlor.Strain Y-4 could also degrade some other pesticides such as pretilachlor and butachlor.