title: Mercury remediation potential of a mercury resistant strain Sphingopyxis sp. SE2 isolated from contaminated soil.
abstract: A mercury resistant bacterial strain SE2 was isolated from contaminated soil. The 16s rRNA gene sequencing confirms the strain as Sphingopyxis belongs to the Sphingomonadaceae family of the α-Proteobacteria group. The isolate showed high resistance to mercury with estimated concentrations of Hg that caused 50% reduction in growth (EC50) of 5.97 and 6.22mg/L and minimum inhibitory concentrations (MICs) of 32.19 and 34.95mg/L in minimal and rich media, respectively. The qualitative detection of volatilized mercury and the presence of mercuric reductase enzyme proved that the strain SE2 can potentially remediate mercury. ICP-QQQ-MS analysis of the remaining mercury in experimental broths indicated that a maximum of 44% mercury was volatilized within 6hr by live SE2 culture. Furthermore a small quantity (23%) of mercury was accumulated in live cell pellets. While no volatilization was caused by dead cells, sorption of mercury was confirmed. The mercuric reductase gene merA was amplified and sequenced. Homology was observed among the amino acid sequences of mercuric reductase enzyme of different organisms from α-Proteobacteria and ascomycota groups.
authors.affiliation: Global Centre for Environmental Remediation (GCER), Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: KhandakerRayhan.Mahbub@uon.edu.au.
authors.forename: Khandaker Rayhan
authors.initials: KR
authors.lastname: Mahbub
authors.affiliation: Global Centre for Environmental Remediation (GCER), Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Kannan
authors.initials: K
authors.lastname: Krishnan
authors.affiliation: Global Centre for Environmental Remediation (GCER), Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia.
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
authors.affiliation: Global Centre for Environmental Remediation (GCER), Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia. Electronic address: megh.mallavarapu@newcastle.edu.au.
authors.forename: Mallavarapu
authors.initials: M
authors.lastname: Megharaj
mesh_terms: D000222:Adaptation, Physiological; D020561:Alphaproteobacteria / Q000378:metabolism / Q000502:physiology*; D001673:Biodegradation, Environmental; D008628:Mercury / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D012336:RNA, Ribosomal, 16S; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D014835:Volatilization
chemical_list: D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D010088:Oxidoreductases; C021551:mercuric reductase; D008628:Mercury
keywords: Mercury reductase; Mercury remediation; Mercury resistance; Mercury volatilization; Sphingopyxis