title: Novel Chryseobacterium sp. PYR2 degrades various organochlorine pesticides (OCPs) and achieves enhancing removal and complete degradation of DDT in highly contaminated soil.
abstract: Long term residues of organochlorine pesticides (OCPs) in soils are of great concerning because they seriously threaten food security and human health. This article focuses on isolation of OCP-degrading strains and their performance in bioremediation of contaminated soil under ex situ conditions. A bacterium, Chryseobacterium sp. PYR2, capable of degrading various OCPs and utilizing them as a sole carbon and energy source for growth, was isolated from OCP-contaminated soil. In culture experiments, PYR2 degraded 80-98% of hexachlorocyclohexane (HCH) or 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) isomers (50 mg L(-1)) in 30 days. A pilot-scale ex situ bioremediation study of highly OCP-contaminated soil augmented with PYR2 was performed. During the 45-day experimental period, DDT concentration was reduced by 80.3% in PYR2-augmented soils (35.37 mg kg(-1) to 6.97 mg kg(-1)) but by only 57.6% in control soils. Seven DDT degradation intermediates (metabolites) were detected and identified in PYR2-augmented soils: five by GC/MS: 1,1-dichloro-2,2-bis (4-chlorophenyl) ethane (DDD), 1,1-dichloro-2,2-bis (4-chlorophenyl) ethylene (DDE), 1-chloro-2,2-bis (4-chlorophenyl) ethylene (DDMU), 1-chloro-2,2-bis (4-chlorophenyl) ethane (DDMS), and dichlorobenzophenone (DBP); and two by LC/MS: 4-chlorobenzoic acid (PCBA) and 4-chlorophenylacetic acid (PCPA). Levels of metabolites were fairly stable in control soils but varied greatly with time in PYR2-augmented soils. Levels of DDD, DDMU, and DDE in PYR2-augmented soils increased from day 0 to day 30 and then decreased by day 45. A DDT biodegradation pathway is proposed based on our identification of DDT metabolites in PYR2-augmented systems. PYR2 will be useful in future studies of OCP biodegradation and in bioremediation of OCP-contaminated soils.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
authors.forename: Guo-Min
authors.initials: GM
authors.lastname: Ai
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China. Electronic address: liuzhp@sun.im.ac.cn.
authors.forename: Zhi-Pei
authors.initials: ZP
authors.lastname: Liu
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D002723:Chlorobenzoates / Q000032:analysis / Q000378:metabolism; D045247:Chryseobacterium / Q000378:metabolism*; D003634:DDT / Q000378:metabolism*; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism; D007536:Isomerism; D010575:Pesticides / Q000032:analysis / Q000378:metabolism*; D010648:Phenylacetates / Q000032:analysis / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D002723:Chlorobenzoates; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D010648:Phenylacetates; D012989:Soil Pollutants; C029716:4-chlorophenylacetic acid; D003634:DDT; C040768:4-chlorobenzoic acid
keywords: Biodegradation; Bioremediation; Chryseobacterium sp. PYR2; DDT; HCH; Organochlorine pesticides