Isolation,Characterization And Degradation Study Of A Fluorene-degradating Strain FLU01

Polycyclic aromatic hydrocarbons(PAHs)are the persistent pollutants with two or more benzene rings,which are widely distributed in soil and other environments.Because of their chemical stability and hydrophobicity,they can be absorbed by organism,then transferred into humans.As the typical carcinogenic,teratogenic and mutagenic compounds,PAHs which are widely scattered and constantly accumulated,also bring human health and ecological safety a great challenge.In this study,a fluorene-degrading strain FLU01 was enriched and isolated from the petrochemical contaminated soil in Qianjiang City,Hubei Province,China.By 16SrDNA analysis,Gram staining and microscopic observation,it was identified as Paracoccus sp FLU01.Then its phospholipid fatty acid composition,carbon source metabolic properties and degradation abilities of PAHs were determined.The results are followed:First,analysis of phospholipid fatty acid composition showed that FLU01 's phospholipid fatty acid composition is similar to Paracoccus sp.,which possesses abundant C19:0 cyclo co8c and C18:l?7c.What's more,FLU01 have a higher abundance of C16:4 w3c and C17:1 w7c,which means that FLU01 we gained is a novel strain of Paracoccus sp.Secondly,FLU01 showed a strong carbon source degradation abilities and widely environmental suitability.The BIOLOG analysis of Carbon Source Microwell Plate indicated that FLU01 possessed a remarkable metabolic activity on many carbon sources,such as N-Acetyl-D-galactosamine,Tween 40,acetoacetic acid,propionic acid and acetic acid,etc FLU01 have a significant resistance to common inhibitors,such as rifamycin SV,incomycin,jiemycin,guanidine hydrochloride,Tetradecyl sodium sulfate,nalidixic acid,lithium chloride,potassium tellurite,sodium butyrate and so on.But it's sensitive to Troleandomycin,Minocycline,Vancomycin,Tetrazolium Violet and Ammonia QuNa sodium bromate.What's more FLU01 cannot grow when pH<6,or the concentration of NaCl>8.Thirdly,FLU01 showed a remarkable degradation activity on fluorene.Using 200 mg/L fluorene as sole carbon source and energy,FLU01 can degrade fluorene to only 17.39±5.82 mg/L in 18 days,with a degradation rate of 91.31%.FLU01 is one of the strains with the highest degradation activity up to now.Fourthly,is is indicated that FLU01 can also degrade other PAHs,biphenyl,phenanthrene,pyrene,fluoranthene.The initial concentration of PAHs,which are the sole carbon source and energy,are 200 mg/L,after 14 days,about 79.71%of phenanthrene,32.54%of pyrene,80.15%of fluorene and 76.94%of fluoranthene have been degraded.In a word,the fluorene-degrading strain FLU01,which belongs to Paracoccus sp.,exhibits the highest degradation activity up to now.Moreover,FLU01 possessed a higher degradation activity on naphthalene,phenanthrene,biphenyl,fluoranthene and pyrene.The use of this bacterium may be an attractive alternative for the bioremediation of polycyclic aromatic hydrocarbons in the environment.