title: Biosurfactant technology for remediation of cadmium and lead contaminated soils.
abstract: This research focuses on column experiments conducted to evaluate the potential of environmentally compatible rhamnolipid biosurfactant produced by Pseudomonas aeruginosa strain BS2 to remove heavy metals (Cd and Pb) from artificially contaminated soil. Results have shown that di-rhamnolipid removes not only the leachable or available fraction of Cd and Pb but also the bound metals as compared to tap water which removed the mobile fraction only. Washing of contaminated soil with tap water revealed that approximately 2.7% of Cd and 9.8% of Pb in contaminated soil was in freely available or weakly bound forms whereas washing with rhamnolipid removed 92% of Cd and 88% of Pb after 36 h of leaching. This indicated that di-rhamnolipid selectively favours mobilization of metals in the order of Cd>Pb. Biosurfactant specificity observed towards specific metal will help in preferential elution of specific contaminant using di-rhamnolipid. It was further observed that pH of the leachates collected from heavy metal contaminated soil column treated with di-rhamnolipid solution was low (6.60-6.78) as compared to that of leachates from heavy metal contaminated soil column treated with tap water (pH 6.90-7.25), which showed high dissolution of metal species from the contaminated soil and effective leaching of metals with treatment with biosurfactant. The microbial population of the contaminated soil was increased after removal of metals by biosurfactant indicating the decrease of toxicity of metals to soil microflora. This study shows that biosurfactant technology can be an effective and nondestructive method for bioremediation of cadmium and lead contaminated soil.
authors.affiliation: Environmental Biotechnology Division, National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India. aa_juwarkar@neeri.res.in
authors.forename: Asha A
authors.initials: AA
authors.lastname: Juwarkar
authors.forename: Anupa
authors.initials: A
authors.lastname: Nair
authors.forename: Kirti V
authors.initials: KV
authors.lastname: Dubey
authors.forename: S K
authors.initials: SK
authors.lastname: Singh
authors.forename: Sukumar
authors.initials: S
authors.lastname: Devotta
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D006017:Glycolipids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry*; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors; D014867:Water
chemical_list: D006017:Glycolipids; D012987:Soil; D012989:Soil Pollutants; D013501:Surface-Active Agents; C051310:rhamnolipid hemolysin, Pseudomonas aeruginosa; D002104:Cadmium; D014867:Water; D007854:Lead