title: High coverage sequencing of DNA from microorganisms living in an oil reservoir 2.5 kilometres subsurface.
abstract: Microorganisms colonize a variety of extreme environments, and based on cultivation studies and analyses of PCR-amplified 16S rDNA sequences, microbial life appears to extend deep into the earth crust. However, none of these studies involved comprehensive characterizations of total DNA. Here we report results of a high-coverage DNA pyrosequencing of an apparently representative and uncontaminated sample from a deep sea oil reservoir located 2.5 km subsurface, attributing a pressure and temperature of 250 bars and 85°C respectively. Bioinformatic analyses of the DNA sequences indicate that the reservoir harbours a rich microbial community dominated by a smaller number of taxa. Comparison of the metagenome with sequences in databases indicated that there may have been contact between the oil reservoir and surface communities late in the sequence of geological events leading to oil reservoir formation. One specific gene, encoding a putative enolase, was synthesized and expressed in Escherichia coli. Enolase activity was confirmed and was found to be much more thermotolerant than for a corresponding E. coli enzyme, consistent with the conditions in the oil reservoir.
authors.affiliation: Statoil ASA, 7053 Ranheim, Norway Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway SINTEF Materials and Chemistry, Department of Biotechnology, 7465 Trondheim, Norway CEES and MERG, Department of Biology, University of Oslo, 0316 Oslo, Norway.
authors.forename: Hans K
authors.initials: HK
authors.lastname: Kotlar
authors.forename: Anna
authors.initials: A
authors.lastname: Lewin
authors.forename: Jostein
authors.initials: J
authors.lastname: Johansen
authors.forename: Mimmi
authors.initials: M
authors.lastname: Throne-Holst
authors.forename: Thomas
authors.initials: T
authors.lastname: Haverkamp
authors.forename: Sidsel
authors.initials: S
authors.lastname: Markussen
authors.forename: Asgeir
authors.initials: A
authors.lastname: Winnberg
authors.forename: Philip
authors.initials: P
authors.lastname: Ringrose
authors.forename: Trine
authors.initials: T
authors.lastname: Aakvik
authors.forename: Einar
authors.initials: E
authors.lastname: Ryeng
authors.forename: Kjetill
authors.initials: K
authors.lastname: Jakobsen
authors.forename: Finn
authors.initials: F
authors.lastname: Drabløs
authors.forename: Svein
authors.initials: S
authors.lastname: Valla