title: Bioremediation of lead contaminated soil with Rhodobacter sphaeroides.
abstract: Bioremediation with microorganisms is a promising technique for heavy metal contaminated soil. Rhodobacter sphaeroides was previously isolated from oil field injection water and used for bioremediation of lead (Pb) contaminated soil in the present study. Based on the investigation of the optimum culturing conditions and the tolerance to Pb, we employed the microorganism for the remediation of Pb contaminated soil simulated at different contamination levels. It was found that the optimum temperature, pH, and inoculum size for R. sphaeroides is 30-35 °C, 7, and 2 × 10(8) mL(-1), respectively. Rhodobacter sphaeroides did not remove the Pb from soil but did change its speciation. During the bioremediation process, more available fractions were transformed to less accessible and inert fractions; in particular, the exchangeable phase was dramatically decreased while the residual phase was substantially increased. A wheat seedling growing experiment showed that Pb phytoavailability was reduced in amended soils. Results inferred that the main mechanism by which R. sphaeroides treats Pb contaminated soil is the precipitation formation of inert compounds, including lead sulfate and lead sulfide. Although the Pb bioremediation efficiency on wheat was not very high (14.78% root and 24.01% in leaf), R. sphaeroides remains a promising alternative for Pb remediation in contaminated soil.
authors.affiliation: School of Space and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, PR China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Space and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, PR China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Peng
authors.affiliation: School of Space and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, PR China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Jia
authors.affiliation: School of Space and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
authors.affiliation: School of Space and Environment, Beihang University, 37 Xueyuan Road, Haidian District, Beijing 100191, PR China. Electronic address: fanwh@buaa.edu.cn.
authors.forename: Wenhong
authors.initials: W
authors.lastname: Fan
mesh_terms: D001673:Biodegradation, Environmental; D007854:Lead / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity; D012242:Rhodobacter sphaeroides / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D014908:Triticum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D007854:Lead
keywords: Bioremediation; Contaminated soil; Lead; Phytoavailability; Rhodobacter sphaeroides