Subsurface metagenomics, functional microbial diversity analysis and gene discovery in deep and hot petroleum reservoirs - Annual report 2009

Annual report VISTA 2009

Subsurface metagenomics, functional microbial diversity analysis
and gene discovery in deep and hot petroleum reservoirs

Project director:                                 Birkeland, Nils Kåre, Centre for Geobiology, UiB
Post-doc/ scholar:                              Keen, Jeffrey
Project duration:                                15.04.09 – 14.04.12
Technical contact person in Statoil:      Last name, First name
Division head:                                    Kotlar, Hans Kristian
Project number:                                 6504

Objectives
The principle objectives of this project are to obtain a better understanding of the diversity, genetics and physiology of the microorganisms indigenous to petroleum reservoirs and to explore their biotechnological potential.

Status:
Enrichment culture analysis has been carried out on produced water from the Valhall field. Samples were taken from the wellhead and from the primary oil separation tanks. These were incubated in a range of anaerobic media at 50, 60, 70 and 80°C. Growth was only observed at 50°C, in the samples from the separation tank.
The wellhead samples appear to contain few if any viable organisms. This is consistent with a reservoir temperature of ~100°C, given that it is currently accepted (though unexplained) that microorganisms are absent from oil formation waters at over 80°C. In contrast, water from the oil separation tanks (@38°C) contained ~107 cells/ml, however part of this may represent displaced biofilm material.

Taxonomic analysis of a 16S rRNA library derived from DNA isolated from the separator tank water suggests that the microbial population was dominated (>90% at the time of sampling) by an organism closely related to the iron and sulphur reducing bacteria Pelobacter carbinolicus. A range of fermentative and nitrate reducing organisms were identified in the enrichment cultures at 50°C. Several of these are related to Anaerophaga thermohalophila, which has been suggested as having potential in microbial enhanced oil recovery. Work is underway to isolate these organisms in pure culture as a prelude to genome sequencing.

A lack of recoverable DNA from the wellhead samples precluded the construction of a Fosmid library or stable isotope probing experiments.

Publications: