title: Isolation and characterization of a hydrocarbonoclastic bacterial enrichment from total petroleum hydrocarbon contaminated sediments: potential candidates for bioaugmentation in bio-based processes.
abstract: Seven hydrocarbonoclastic new bacterial isolates were isolated from dredged sediments of a river estuary in Italy. The sediments were contaminated by shipyard activities since decades, mainly ascribable to the exploitation of diesel oil as the fuel for recreational and commercial navigation of watercrafts. The bacterial isolates were able to utilize diesel oil as sole carbon source. Their metabolic capacities were evaluated by GC-MS analysis, with reference to the depletion of both the normal and branched alkanes, the nC18 fatty acid methyl ester and the unresolved complex mixture of organic compounds. They were taxonomically identified as different species of Stenotrophomonas and Pseudomonas spp. by the combination of amplified ribosomal DNA restriction analysis (ARDRA) and repetitive sequence-based PCR (REP-PCR) analysis. The metabolic activities of interest were analyzed both in relation to the single bacterial strains and to the combination of the latter as a multibacterial species system. After 6 days of incubation in mineral medium with diesel oil as sole carbon source, the Stenotrophomonas sp. M1 strain depleted 43-46 % of Cn-alkane from C28 up to C30, 70 % of the nC18 fatty acid methyl ester and the 46 % of the unresolved complex mixture of organic compounds. On the other hand, the Pseudomonas sp. NM1 strain depleted the 76 % of the nC18 fatty acid methyl ester, the 50 % of the unresolved complex mixture of organic compounds. The bacterial multispecies system was able to completely deplete Cn-alkane from C28 up to C30 and to deplete the 95 % of the unresolved complex mixture of organic compounds. The isolates, either as single strains and as a bacterial multispecies system, were proposed as candidates for bioaugmentation in bio-based processes for the decontamination of dredged sediments.
authors.affiliation: Department of Biology, University of Pisa, 56126, Pisa, Italy. sdigregorio@biologia.unipi.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Di Gregorio
authors.affiliation: Department of Biology, University of Pisa, 56126, Pisa, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Siracusa
authors.affiliation: Department of Biology, University of Pisa, 56126, Pisa, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Becarelli
authors.affiliation: Department of Biology, University of Pisa, 56126, Pisa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Mariotti
authors.affiliation: Teseco Spa, Via Carlo Ludovico Ragghianti 12, 56121, Pisa, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gentini
authors.affiliation: Department of Biology, University of Pisa, 56126, Pisa, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Lorenzi
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology*; D006838:Hydrocarbons / Q000032:analysis*; D059013:Microbial Consortia / Q000235:genetics; D010578:Petroleum / Q000032:analysis*; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism; D012329:RNA, Bacterial / Q000235:genetics; D020588:Stenotrophomonas / Q000235:genetics / Q000378:metabolism
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D012329:RNA, Bacterial
keywords: Alkanes; Bacterial consortium; Diesel oil; Dredged sediment; Unresolved complex mixture; nC18 fatty acid methyl ester