Methanotrophic bacteria in oilsands tailings ponds of northern Alberta

• Published in: The ISME Journal Vol. 7; no. 5; pp. 908 - 921
• Main Authors: Saidi-Mehrabad, Alireza, He, Zhiguo, Tamas, Ivica, Sharp, Christine E, Brady, Allyson L, Rochman, Fauziah F, Bodrossy, Levente, Abell, Guy CJ, Penner, Tara, Dong, Xiaoli, Sensen, Christoph W, Dunfield, Peter F
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-05-2013; Nature Publishing Group
• Subjects: 631/158/2459; 631/158/47; 631/326/41/2142; Alberta; Bacteria - classification; Bacteria - genetics; Bacteria - metabolism; Biomedical and Life Sciences; Carbon fixation; Clay; Deoxyribonucleic acid; Detoxification; DNA; DNA, Bacterial - genetics; Ecology; Evolutionary Biology; Formaldehyde; Gammaproteobacteria - classification; Gammaproteobacteria - genetics; Gammaproteobacteria - isolation & purification; Gammaproteobacteria - metabolism; Geologic Sediments - microbiology; Hydrocarbons; Lakes; Life Sciences; Metagenome; Methane; Methane - metabolism; Methylocaldum; Methylococcaceae - classification; Methylococcaceae - genetics; Methylococcaceae - metabolism; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Mine tailings; Oil sands; Original; original-article; Oxidation; Petroleum - microbiology; Phylogeny; Polymerase Chain Reaction; Ponds; Ponds - microbiology; RNA, Ribosomal, 16S - genetics; Silt; Stable isotopes; Surface water; Alberta; methanotroph; methane; oilsands; tailings pond
• ISSN: 1751-7362; 1751-7370
• DOI: 10.1038/ismej.2012.163

We investigated methanotrophic bacteria in slightly alkaline surface water (pH 7.4–8.7) of oilsands tailings ponds in Fort McMurray, Canada. These large lakes (up to 10 km
2
) contain water, silt, clay and residual hydrocarbons that are not recovered in oilsands mining. They are primarily anoxic and produce methane but have an aerobic surface layer. Aerobic methane oxidation was measured in the surface water at rates up to 152 nmol CH
4
 ml
−1
water d
−1
. Microbial diversity was investigated via pyrotag sequencing of amplified 16S rRNA genes, as well as by analysis of methanotroph-specific
pmoA
genes using both pyrosequencing and microarray analysis. The predominantly detected methanotroph in surface waters at all sampling times was an uncultured species related to the gammaproteobacterial genus
Methylocaldum
, although a few other methanotrophs were also detected, including
Methylomonas
spp. Active species were identified via
13
CH
4
stable isotope probing (SIP) of DNA, combined with pyrotag sequencing and shotgun metagenomic sequencing of heavy
13
C-DNA. The SIP-PCR results demonstrated that the
Methylocaldum
and
Methylomonas
spp. actively consumed methane in fresh tailings pond water. Metagenomic analysis of DNA from the heavy SIP fraction verified the PCR-based results and identified additional
pmoA
genes not detected via PCR. The metagenome indicated that the overall methylotrophic community possessed known pathways for formaldehyde oxidation, carbon fixation and detoxification of nitrogenous compounds but appeared to possess only particulate methane monooxygenase not soluble methane monooxygenase.