title: Bioremediation of Cd and carbendazim co-contaminated soil by Cd-hyperaccumulator Sedum alfredii associated with carbendazim-degrading bacterial strains.
abstract: The objective of this study was to develop a bioremediation strategy for cadmium (Cd) and carbendazim co-contaminated soil using a hyperaccumulator plant (Sedum alfredii) combined with carbendazim-degrading bacterial strains (Bacillus subtilis, Paracoccus sp., Flavobacterium and Pseudomonas sp.). A pot experiment was conducted under greenhouse conditions for 180 days with S. alfredii and/or carbendazim-degrading strains grown in soil artificially polluted with two levels of contaminants (low level, 1 mg kg(-1) Cd and 21 mg kg(-1) carbendazim; high level, 6 mg kg(-1) Cd and 117 mg kg(-1) carbendazim). Cd removal efficiencies were 32.3-35.1 % and 7.8-8.2 % for the low and high contaminant level, respectively. Inoculation with carbendazim-degrading bacterial strains significantly (P < 0.05) increased Cd removal efficiencies at the low level. The carbendazim removal efficiencies increased by 32.1-42.5 % by the association of S. alfredii with carbendazim-degrading bacterial strains, as compared to control, regardless of contaminant level. Cultivation with S. alfredii and inoculation of carbendazim-degrading bacterial strains increased soil microbial biomass, dehydrogenase activities and microbial diversities by 46.2-121.3 %, 64.2-143.4 %, and 2.4-24.7 %, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that S. alfredii stimulated the activities of Flavobacteria and Bradyrhizobiaceae. The association of S. alfredii with carbendazim-degrading bacterial strains enhanced the degradation of carbendazim by changing microbial activity and community structure in the soil. The results demonstrated that association of S. alfredii with carbendazim-degrading bacterial strains is promising for remediation of Cd and carbendazim co-contaminated soil.
authors.affiliation: Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Wendan
authors.initials: W
authors.lastname: Xiao
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Tingqiang
authors.initials: T
authors.lastname: Li
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhenli
authors.initials: Z
authors.lastname: He
authors.forename: Xiaoe
authors.initials: X
authors.lastname: Yang
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D001562:Benzimidazoles / Q000032:analysis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D002219:Carbamates / Q000032:analysis / Q000378:metabolism*; D031963:Sedum / Q000378:metabolism* / Q000382:microbiology; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; C006698:carbendazim