Study On The Degradation Characeristics Of Strain N80to The Chlormuron-ethyl And Bioremediation Of Contaminated Soil

Chlorimuron-ethyl is an herbicide which can control broadleave weeds and some grassed in the soybean field effectively. However, it is reported that serious damage to ratation and substitution crops are coursed by the residual of chlorimuron-ethyl in soil. Therefore, removal of chlorine-ethyl residues in soil and elimination of residual effects on substitution crops has great significance. A strain N80(Serratia marcecens) screened out from laboratory was used to research its characterization of degradation, repair of contaminated soil.The main points of research were shown as follow:Strain N80(Serratia marcecens) is a degrading bacteria grows with Chlorimuron-ethyl as only nitrogen source. Its suitable temperature of degradation is30℃-35℃, and the suitable PH value is7. The best amount of bacteria is3%of seed liquor. Because of high concentration of Chlorimuron-ethyl has inhibitory action to strain N80, the optimal concentration of degradation is20mg/L. According to the single factor experiment, the better conditions were to design the L9(34) test, and screened best proportion for degradation is PH5.0, temperature35℃, amount Of bacteria is3%, the initial concentration of Chlorimuron-ethyl is50mg/L.On the other hand, this paper also research the influencing factors of strain N80repairing the contaminated soil by chlorimuron-ethyl under laboratory conditions. The verification conclusions were:Addition of strain N80in soil can promote the degradation of chlorimuron-ethyl, the highest degradation efficiency is94%for30d.The degradation rate in unsterilized soil is faster than in sterilized soil.The optimal amount of stain N80in soil is0.5×105CFU/g.Different original concentration of liquid medicine have impact on degradation:the degradation efficiency raises with increasing of liquid medicine concentration under low original concentration of liquid medicine, high concentration of Chlorimuron-ethyl has inhibitory action to strain N80.Different water content of soil also has a great effect,30%water content is the optimal condition that the degradation efficiency is87.5%. However, exorbitant and low water content will decrease the degradation efficiency. The stain N80works in different kind of soils has different degradation efficiency, the black soil is better than umber. Pot experiment showed that:N80strain could effectively increase degradation rate of Chlorimuron-ethyl in contaminated soil and remove phytoxicity.