【摘要】 从长期受毒死蜱污染的污水处理池中分离到一株毒死蜱高效降解菌株,命名为Dsp-2。经生理生化和16S rDNA序列同源性分析,鉴定其为鞘胺醇单胞菌属(Sphingomonas sp.)细菌。该菌株能在24 h内完全降解100 mg L-1的毒死蜱,降解特性的研究表明:随着农药浓度的加大,绝对降解量也增大,但高浓度的毒死蜱会导致不能完全降解;起始接种量和降解毒死蜱的速率呈正相关;外加氮源营养能够明显促进降解;1 mmol L-1的Fe3+和Ni2+等对其降解性能有抑制作用。研究了Dsp-2在土壤中降解毒死蜱的效果。结果表明,Dsp-2在三种供试土壤中都能有效的降解毒死蜱,其中在潮土中降解的速率最快,且当毒死蜱的浓度范围在1~100 mg kg-1内Dsp-2都能有效的降解毒死蜱,7 d降解率达到85%~98%。更多还原

【Abstract】 A strain of bacterium designated as Strain Dsp-2,capable of degrading chlorpyrifos efficiently,was isolated from sludge in a wastewater treatment installation that has long been treating chlorpyrifos polluted water.Strain Dsp2 was identified preliminarily as Sphingomonas.sp based on its physiological and biochemical characters and the result of the 16 S rDNA homologue sequence analysis.Strain Dsp-2 can grow with chlorpyrifos as its sole carbon source,degrading 100 mg L-1of chlorpyrifos completely within 24 h.Results of its degradation characteristics show that the degradation rate of chlorpyrifos was increased considerably with the concentration.But when the chlprpyrifos concentration was higher than 200 mg L-1,the strain Dsp-2 stopped degrading.Effects of initial inoculum size,yeast extract,glucose,peptone and metal ion on degradation of chlorpyrifos by Dsp-2 were also studied.Results show that large initial inoculum size and a proper amount of peptone could promote its degradation of chlorpyrifos.1 mmol L-1of Fe3+and Ni2+could restrain its degradation rate of chlorpyrifos.Addition of strain Dsp-2 to three test soils treated with chlorpyrifos resulted in a higher degradation rate of chlorpyrifos than in the control,soils without inoculation.However,the highest rate was showed in brown soil,which indicated moderate pH,moisture and nutrients could promote the degradation.The degradation rate reached to 85%～98% at 7th day when the concentration of chlorpyrifos ranged in 1～100 mg kg-1.更多还原