title: Enhancement of biodegradation of oil adsorbed on fine soils in a bioslurry reactor.
abstract: Techniques for enhancing the biodegradation of oil-contaminated fine soils in a slurry-phase bioreactor were investigated. Using a model system consisting of kaolin particles containing adsorbed n-dodecane as a diesel fuel surrogate, we investigated how increasing the temperature and adding a surfactant and various hydrophobic support media affected the biodegradation rate of n-dodecane. Increasing the temperature from 25 to 35 degrees C decreased the time required for complete degradation of n-dodecane by 30%, from 110h to 80h. Addition of the surfactant polyethylene glycol p-1,1,3,3-tetramethylbutylphenyl ether decreased the degradation time to less than 48h at 35 degrees C, although a high concentration of the surfactant (3000mgl(-1)) was required. We suspect that the surfactant increased the degradation rate by solubilizing the n-dodecane into the solution phase in which the microorganisms were suspended. We tested five types of organic polymers as support media for the microorganisms and found that the biodegradation time could be reduced by approximately 50% with a support medium made from polyurethane; in the presence of this medium, only 36h was required for complete decomposition at 35 degrees C. The reduction in the degradation time was probably due to transfer of the n-dodecane from the soil to the support medium, which improved contact between the n-dodecane and the microorganisms. The polyurethane support medium bearing the microorganisms was stable and could be reused.
authors.affiliation: Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513, Japan. aqua@hiroshima-u.ac.jp
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Okuda
authors.forename: Martha E
authors.initials: ME
authors.lastname: Alcántara-Garduño
authors.forename: Masahiro
authors.initials: M
authors.lastname: Suzuki
authors.forename: Chikara
authors.initials: C
authors.lastname: Matsui
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kose
authors.forename: Wataru
authors.initials: W
authors.lastname: Nishijima
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Okada
mesh_terms: D000327:Adsorption; D000473:Alkanes / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors; D010578:Petroleum / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D000473:Alkanes; D010578:Petroleum; D012989:Soil Pollutants; D013501:Surface-Active Agents; C007548:n-dodecane