title: Bioremediation of petroleum-contaminated soil by a combined system of biostimulation-bioaugmentation with yeast.
abstract: This paper presents a study of the effect of a combined biostimulation-bioaugmentation treatment applied to a clay-loam soil contaminated with 16,300 mg/kg of total petroleum hydrocarbons (TPH), which comprised 51% saturated hydrocarbons and 31% aromatic hydrocarbons. The bioaugmentation was performed with yeast Candida tropicalis SK21 isolated from petroleum-contaminated soil. The strain was able to grow in a pH range of 3-9 in liquid culture, and the optimum pH was found to be 6 for both growth and biosurfactant production. At pH 6, 96% and 42% of TPH were degraded by the strain at the initial diesel oil concentrations of 0.5% and 5% (v/v), respectively. The remediation via inoculating the yeast removed 83% of TPH in 180 days while the experiment with the indigenous microorganisms alone removed 61%. Microbial enumeration showed that the yeast SK21 could grow good in the soil. It was also found that dehydrogenase and polyphenoloxidase activities in soil were remarkably enhanced by the inoculation of the yeast.
authors.affiliation: China University of Geosciences, Lumo Road, Wuhan 430074, People's Republic of China. meiying_fan@163.com
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Fan
authors.affiliation: School of Geophysics and Oil Resources, Yangtze University, Xueyuan Road, Jingzhou 434023, People's Republic of China.
authors.forename: Rui-Jie
authors.initials: RJ
authors.lastname: Xie
authors.affiliation: College of Engineering and Technology, Yangtze University, Xueyuan Road, Jingzhou 434020, People s Republic of China.
authors.forename: Gang
authors.initials: G
authors.lastname: Qin
mesh_terms: D001673:Biodegradation, Environmental; D041022:Candida tropicalis / Q000145:classification* / Q000502:physiology*; D049109:Cell Proliferation; D002470:Cell Survival; D010578:Petroleum / Q000032:analysis / Q000382:microbiology*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000302:isolation & purification / Q000378:metabolism*; D013045:Species Specificity; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D010578:Petroleum; D012989:Soil Pollutants