title: Genetically engineered Pseudomonas putida X3 strain and its potential ability to bioremediate soil microcosms contaminated with methyl parathion and cadmium.
abstract: A multifunctional Pseudomonas putida X3 strain was successfully engineered by introducing methyl parathion (MP)-degrading gene and enhanced green fluorescent protein (EGFP) gene in P. putida X4 (CCTCC: 209319). In liquid cultures, the engineered X3 strain utilized MP as sole carbon source for growth and degraded 100 mg L(-1) of MP within 24 h; however, this strain did not further metabolize p-nitrophenol (PNP), an intermediate metabolite of MP. No discrepancy in minimum inhibitory concentrations (MICs) to cadmium (Cd), copper (Cu), zinc (Zn), and cobalt (Co) was observed between the engineered X3 strain and its host strain. The inoculated X3 strain accelerated MP degradation in different polluted soil microcosms with 100 mg MP kg(-1) dry soil and/or 5 mg Cd kg(-1) dry soil; MP was completely eliminated within 40 h. However, the presence of Cd in the early stage of remediation slightly delayed MP degradation. The application of X3 strain in Cd-contaminated soil strongly affected the distribution of Cd fractions and immobilized Cd by reducing bioavailable Cd concentrations with lower soluble/exchangeable Cd and organic-bound Cd. The inoculated X3 strain also colonized and proliferated in various contaminated microcosms. Our results suggested that the engineered X3 strain is a potential bioremediation agent showing competitive advantage in complex contaminated environments.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.|Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, 4888 Shengbei Rd, Changchun, 130102, China.
authors.forename: Xingjian
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China. wlchen@mail.hzau.edu.cn.
authors.forename: Wenli
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China. qyhuang@mail.hzau.edu.cn.|Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China. qyhuang@mail.hzau.edu.cn.
authors.forename: Qiaoyun
authors.initials: Q
authors.lastname: Huang
mesh_terms: D001673:Biodegradation, Environmental; D001711:Biotransformation; D002104:Cadmium / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D003035:Cobalt / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D060847:Metabolic Engineering; D008743:Methyl Parathion / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D016958:Pseudomonas putida / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D012989:Soil Pollutants; D002104:Cadmium; D003035:Cobalt; D008743:Methyl Parathion; D002244:Carbon; D003300:Copper; D015032:Zinc
keywords: Bioremediation; Cadmium; Genetically engineered strain; Methyl parathion