title: Application of PCR-DGGE to analyse the yeast population dynamics in slurry reactors during degradation of polycyclic aromatic hydrocarbons in weathered oil.
abstract: Slurry-phase reactors have been used to investigate the biodegradation feasibility of polycyclic aromatic hydrocarbons (PAHs) in weathered crude oil, by mixed culture containing five PAHs-degrading yeast strains. Yeasts were isolated from the oily soil by enrichment culture, using phenanthrene as a sole carbon source, and identified based on the 26S ribosomal DNA (rDNA) sequence. Yeast strains belonged to the genera Candida, Pichia, Rhodotorula and Sporidiobolus. The experiment was carried out for a period of 6 weeks at room temperature with a solid : liquid ratio of 50% w/w. The results showed that high removal efficiency was obtained for all PAHs, including low molecular weight (LMW) and high molecular weight (HMW) compounds (89.3-98.6% and 66.3-89.4% within 6 weeks, respectively). The higher removal efficiency for HMW-PAHs obtained in this work suggested that yeast strains mixture could play an important role to reclaim oil-contaminated sites. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified 26S rRNA genes was used to follow the changes of yeast populations during the slurry reactor process. The results of DGGE indicated that Candida maltosa-like and Pichia guilliermondii were the dominant species but Rhodotorula dairenensis appeared as a weak band and Sporidiobolus salmonicolor and Pichia anomala disappeared during the study. Moreover, the results showed that all of the five strains, including the two belonging to the same genus, could be differentiated from each other in the DGGE profile.
authors.affiliation: Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, PO Box 2871, Beijing 100085, People's Republic of China.
authors.forename: Abd
authors.initials: A
authors.lastname: El-Latif Hesham
authors.forename: Sardar
authors.initials: S
authors.lastname: Khan
authors.forename: XinChun
authors.initials: X
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D001483:Base Sequence; D001673:Biodegradation, Environmental; D019149:Bioreactors; D016172:DNA Fingerprinting; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D010578:Petroleum / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D015003:Yeasts / Q000235:genetics / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D012989:Soil Pollutants