Enhanced removal of selected hydrocarbons from soil by Pseudomonas aeruginosa UG2 biosurfactants and some chemical surfactants

Abstract

Abstract:The ability of rhamnolipid biosurfactants produced by Pseudomonas aeruginosa UG2 to wash a model hydrocarbon mixture from unsaturated soil columns was studied. Both aliphatic and aromatic hydrocarbons were effectively removed without soil clogging with non-recirculating biosurfactant solutions. Recirculation of wash solutions did not substantially affect washing efficiency. Of the several chemical surfactants tested, only Triton X-100 provided comparable hydrocarbon washing efficiency without soil clogging. The results suggest that UG2 biosurfactants have the potential for remediation of hydrophobic pollutants in unsaturated soil.

Selection and identification of bacteria isolated from waste crude oil with polycyclic aromatic hydrocarbons removal capacities

“…Production of exopolymers with biosurfactant or bioemulsifier activities by the selected strains was studied according to methods previously reported by Quesada et al [21] and Scheibenbogen et al [25]. Erlenmeyer flasks of 500 ml containing 100 ml of NB medium were inoculated with 1 ml of a 24 h culture of microorganisms grown in the same medium.…”

“…After incubation at 32 1C for 8 days, the cultures were centrifuged at 36,000g in a Sorval RC-5B refrigerated centrifuge at 4 1C for 60 min. Supernatants obtained were precipitate either with cold ethanol for the isolation of exopolysaccharides [21] or with HCl at pH 2 for the isolation of rhamnolipids [25]. The biopolymers of the precipitated were dissolved in distilled water, dialysed…”

Degradation ofn-Hexadecane and Its Metabolites byPseudomonas aeruginosaunder Microaerobic and Anaerobic Denitrifying Conditions

“…Compared to other anaerobic respiration mechanisms, denitrification is more favorable energetically, and benign nitrogen (N 2 ) is the predominant product of this process (17,29). The rhamnolipids produced are also very beneficial to bioremediation, because they solubilize and mobilize hydrocarbons and other non-aqueous-phase liquids into the aqueous phase, where they can be biodegraded or removed by advective transport (2,37).…”

The Definition, Preparation and Application of Rhamnolipids as Biosurfactants

“…In another experiment, Shabtai and Gutnick demonstrated a 25-70% and 40-80% increase in the recovery of hydrocarbons from contaminated sandy-loam and silt-loam soil, respectively [75]. In another report, 56% and 73% of the aliphatic and aromatic hydrocarbons, respectively, were recovered from contaminated sandy-loam soil when treated with Rhamnolipids [76]. The ability of rhamnolipids biosurfactants to emulsify hydrocarbon-water mixtures, degrade hydrocarbons in oil spill management, and remediate metal contaminated soil has been well documented [77][78].…”