Study On The Effect Of The Addition Of Corn Stover And Cellulolytic Bacteria On The Microbial Remediation Of Fluoranthene Contaminated Soil

Polycyclic aromatic hydrocarbons(PAHs)are a kind of persistent organic pollutants,which are ubiquitous in agricultural soils in China.Fluoranthene is a typical high molecular weight polycyclic aromatic hydrocarbon with high detection frequency and abundance in soil.In this paper,corn stover and cellulolytic bacteria MYB3 were added to the experiment of microbial degradation of fluoranthene in different environments(minimal salt medium,soil slurry),and their promoting effect and degradation characteristics on the microbial degradation of fluoranthene were analyzed First of all,the promoting effect of corn stover and cellulolytic bacteria MYB3 on the microbial degradation of fluoranthene was verified in liquid environment.After that,the best inoculation number of the complex microorganism of different fluoranthene degrading bacteria YN420,YN1,E420 was determined by orthogonal experiment,and applied to the microbial remediation experiment of fluoranthene contaminated soil.The effects of corn stover with different particle sizes(?0.355mm,0.355?2mm,2?5mm and 5?10mm)on the microbial degradation of fluoranthene of the complex microorganism were investigated.Finally,the effects of corn stover and cellulolytic bacteria MYB3 on the microbial remediation of fluoranthene in fluoranthene contaminated dark brown soil,fluoranthene contaminated aeolian sandy soil and fluoranthene contaminated black soil were studied,and the correlation between the concentration of organic acids in soil and the degradation rate of fluoranthene in soil was analyzed.The results showed that:In the experiment of fluoranthene microbial degradation in liquid environment,the fluoranthene degradation rate of treatment 4(bacteria YN420+corn stover+bacteria MYB3)was the highest,reaching 87.98%after 10 days.The addition of corn stover and cellulolytic bacteria MYB3 increased the degradation of fluoranthene by fluoranthene degrading bacteria YN420 in liquid environment.By using the method of orthogonal experiment,it was determined that the best inoculation number of the complex microorganism was YN420:YN1:E420=2:1:1 When the complex microorganism and corn stover with different particle sizes were added to the fluoranthene contaminated soil for fluoranthene microbial degradation experiment,the fluoranthene degradation rate of combination 5(complex microorganism+bacteria MYB3+particle size 2?5mm corn stover)was the highest,reaching 16.27%after 10 days.Particle size will affect the degradation of corn stover,thus affecting the concentration of organic acids in soil.The results of correlation analysis showed that there was a very significant positive correlation between the degradation rate of fluoranthene and the total concentration of organic acids(p<0.01).In the microbial degradation experiments of fluoranthene contaminated soil slurry with three different textures,experiment 5(unsterilized soil+ complex microorganism+corn stover+bacteria MYB3)had the highest degradation rate of fluoranthene in the three kinds of soil,the degradation rates of fluoranthene in dark brown soil,aeolian sandy soil and black soil were 35.95%,39.1 8%and 24.26%after 20 days,respectively.The addition of corn stover increased the concentration of organic acids in soil,which enhanced the bioavailability of fluoranthene in contaminated soil and promoted the microbial degradation of fluoranthene.Soil texture can affect the release of bound fluoranthene by organic acids.The higher the content of soil organic matter and soil clay,the lower the correlation between the degradation rate of fluoranthene and the total concentration of organic acids,and the lower the degradation rate of fluoranthene in contaminated soil.In three kinds of fluoranthene contaminated soil,the combined treatment of corn stover,cellulolytic bacteria MYB3 and complex microorganism with different inoculation number promoted the microbial remediation of fluoranthene in fluoranthene contaminated soil.