title: Application of aqueous saponin on the remediation of polycyclic aromatic hydrocarbons-contaminated soil.
abstract: The aim of this research was to evaluate the feasibility of aqueous saponin for the removal and biodegradation of polycyclic aromatic hydrocarbons (PAHs) from contaminated soil. Dissolution test confirmed the ability of saponin to increase the apparent solubility of the tested 3-5 rings PAH above the critical micelle concentration (approximately 1000 mg/L). Microbial test with pure culture of Sphingomonas sp. showed that saponin significantly enhanced the degradation of pyrene. For example, the percent degradation was 2.1 times higher in the presence of 2500 mg/L saponin than that of control without saponin after 60 hours incubation at around 10(8) CFU/mL initial cell loading. These results suggest that the binding of pyrene with saponin does not pose a serious constraint to bacterial uptake. Contrary to pyrene, saponin was chemically stable against the PAHs degrader. It is also not toxic to the cell at least up to 2500 mg/L. Finally, using a spiked soil sample, extraction tests with 10,000 mg/L of saponin showed that around 52.7% and 0.3% of pyrene was removed from low and high organic spiked soils, respectively. The results from this study indicate that aqueous saponin is appropriate as a washing agent as well as biodegradation enhancer for the detoxification of PAHs-contaminated low organic carbon soil.
authors.affiliation: Department of Chemistry and Material Engineering, Ibaraki National College of Technology, Hitachinaka, Ibaraki, Japan. kobayashi@chem.ibaraki-ct.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Kaminaga
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Navarro
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Iimura
mesh_terms: D001673:Biodegradation, Environmental; D052918:Environmental Restoration and Remediation / Q000379:methods*; D011083:Polycyclic Compounds / Q000302:isolation & purification*; D011721:Pyrenes / Q000737:chemistry / Q000378:metabolism; D012503:Saponins / Q000737:chemistry* / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000302:isolation & purification*; D012995:Solubility; D020578:Sphingomonas / Q000378:metabolism; D013500:Surface Tension; D014867:Water / Q000737:chemistry
chemical_list: D011083:Polycyclic Compounds; D011721:Pyrenes; D012503:Saponins; D012989:Soil Pollutants; D014867:Water; C030984:pyrene