title: In situ biosurfactant production and hydrocarbon removal by Pseudomonas putida CB-100 in bioaugmented and biostimulated oil-contaminated soil.
abstract: In situ biosurfactant (rhamnolipid) production by Pseudomonas putida CB-100 was achieved during a bioaugmented and biostimulated treatment to remove hydrocarbons from aged contaminated soil from oil well drilling operations. Rhamnolipid production and contaminant removal were determined for several treatments of irradiated and non-irradiated soils: nutrient addition (nitrogen and phosphorus), P. putida addition, and addition of both (P. putida and nutrients). The results were compared against a control treatment that consisted of adding only sterilized water to the soils. In treatment with native microorganisms (non-irradiated soils) supplemented with P. putida, the removal of total petroleum hydrocarbons (TPH) was 40.6%, the rhamnolipid production was 1.54 mg/kg, and a surface tension of 64 mN/m was observed as well as a negative correlation (R = -0.54; p < 0.019) between TPH concentration (mg/kg) and surface tension (mN/m), When both bacteria and nutrients were involved, TPH levels were lowered to 33.7%, and biosurfactant production and surface tension were 2.03 mg/kg and 67.3 mN/m, respectively. In irradiated soil treated with P. putida, TPH removal was 24.5% with rhamnolipid generation of 1.79 mg/kg and 65.6 mN/m of surface tension, and a correlation between bacterial growth and biosurfactant production (R = -0.64; p < 0.009) was observed. When the nutrients and P. putida were added, TPH removal was 61.1%, 1.85 mg/kg of biosurfactants were produced, and the surface tension was 55.6 mN/m. In summary, in irradiated and non-irradiated soils, in situ rhamnolipid production by P. putida enhanced TPH decontamination of the soil.
authors.affiliation: Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico. ; Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, Col. San Pedro Zacatenco, Mexico, D.F., Mexico.
authors.forename: Martínez-Toledo
authors.initials: MT
authors.lastname: Ángeles
authors.forename: Rodríguez-Vázquez
authors.initials: RV
authors.lastname: Refugio
mesh_terms: D006017:Glycolipids / Q000378:metabolism*; D006838:Hydrocarbons / Q000378:metabolism*; D010578:Petroleum / Q000378:metabolism*; D016958:Pseudomonas putida / Q000254:growth & development / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D006017:Glycolipids; D006838:Hydrocarbons; D010578:Petroleum; D012989:Soil Pollutants; D013501:Surface-Active Agents; C418382:rhamnolipid
keywords: P. putida; bioremediation; irradiated soil; rhamnolipids; total petroleum hydrocarbons