title: Sphingomonas from petroleum-contaminated soils in Shenfu, China and their PAHs degradation abilities.
abstract: Members of the Sphingomonas genus are often isolated from petroleum-contaminated soils due to their unique abilities to degrade polycyclic aromatic hydrocarbons (PAHs), which are important for in situ bioremediation. In this study, a combined phenotypic and genotypic approach using streptomycin-containing medium and Sphingomonas-specific PCR was developed to isolate and identify culturable Sphingomonas strains present in petroleum-contaminated soils in the Shenfu wastewater irrigation zone. Of the 15 soil samples examined, 12 soils yielded yellow streptomycin-resistant colonies. The largest number of yellow colony-forming units (CFUs) could reach 10(5)CFUsg(-1)soil. The number of yellow CFUs had a significant positive correlation (p<0.05) with the ratio of PAHs to total petroleum hydrocarbons (TPH), indicating that Sphingomonas may play a key role in degrading the PAH fraction of the petroleum contaminants at this site. Sixty yellow colonies were selected randomly and analyzed by colony PCR using Sphingomonas-specific primers, out of which 48 isolates had PCR-positive signals. The 48 positive amplicons generated 8 distinct restriction fragment length polymorphism (RFLP) patterns, and 7 out of 8 phylotypes were identified as Sphingomonas by 16S rRNA gene sequencing of the representative strains. Within these 7 Sphingomonas strains, 6 strains were capable of using fluorene as the sole carbon source, while 2 strains were phenanthrene-degrading Sphingomonas. To the best of our knowledge, this is the first report to evaluate the relationship between PAHs contamination levels and culturable Sphingomonas in environmental samples.
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Lisha
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China; State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China. Electronic address: huili@iae.ac.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Siqin
authors.initials: S
authors.lastname: Han
authors.affiliation: Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
mesh_terms: D001673:Biodegradation, Environmental; D002681:China; D010578:Petroleum / Q000032:analysis; D010802:Phylogeny; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D020578:Sphingomonas / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants
keywords: Degradation; Genus; Polycyclic aromatic hydrocarbons (PAHs); Sphingomonas