title: Biosurfactant from red ash trees enhances the bioremediation of PAH contaminated soil at a former gasworks site.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are persistent contaminants that accumulate in soil, sludge and on vegetation and are produced through activities such as coal burning, wood combustion and in the use of transport vehicles. Naturally occurring surfactants have been known to enhance PAH-removal from soil by improving PAH solubilization thereby increasing PAH-microbe interactions. The aim of this research was to determine if a biosurfactant derived from the leaves of the Australian red ash (Alphitonia excelsa) would enhance bioremediation of a heavily PAH-contaminated soil and to determine how the microbial community was affected. Results of GC-MS analysis show that the extracted biosurfactant was significantly more efficient than the control in regards to the degradation of total 16 US EPA priority PAHs (78.7% degradation compared to 62.0%) and total petroleum hydrocarbons (TPH) (92.9% degradation compared to 44.3%). Furthermore the quantification of bacterial genes by qPCR analysis showed that there was an increase in the number of gene copies associated with Gram positive PAH-degrading bacteria. The results suggest a commercial potential for the use of the Australian red ash tree as a source of biosurfactant for use in the accelerated degradation of hydrocarbons.
authors.affiliation: Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
authors.forename: Warren
authors.initials: W
authors.lastname: Blyth
authors.affiliation: Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia. Electronic address: esmaeil.shahsavari@rmit.edu.au.
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Shahsavari
authors.affiliation: Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Morrison
authors.affiliation: Centre for Environmental Sustainability and Remediation, School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Ball
mesh_terms: D001673:Biodegradation, Environmental; D008401:Gas Chromatography-Mass Spectrometry; D006094:Gram-Positive Bacteria / Q000235:genetics / Q000378:metabolism; D059013:Microbial Consortia / Q000235:genetics; D009517:New South Wales; D010578:Petroleum; D018515:Plant Leaves / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D027823:Rhamnaceae / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D013501:Surface-Active Agents / Q000032:analysis / Q000302:isolation & purification
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D013501:Surface-Active Agents
keywords: Bioremediation; Biosurfactant; DGGE; Polycyclic aromatic hydrocarbons; Red ash tree; qPCR