Methylicorpusculum Oleiharenae Gen. Nov., Sp. Nov., An Aerobic Methanotroph Isolated From An Oil Sands Tailings Pond

An aerobic methane oxidizing bacterium, designated XLMV4(T), was isolated from the oxic surface layer of an oil sands tailings pond in Alberta, Canada. Strain XLMV4(T) is capable of growth on methane and methanol as energy sources. NH4Cl and sodium nitrate are nitrogen sources. Cells are Gram-negative, beige to yellow-pigmented, motile (via a single polar flagellum), short rods 2.0-3.3 mu m in length and 1.0-1.6 mu m in width. A thick capsule is produced. Surface glycoprotein or cup shape proteins typical of the genera Methylococcus. Methylothermus and Methylomicrobium were not observed. Major isoprenoid quinones are 0-8 and Q-7 at an approximate molar ratio of 71:22. Major polar lipids are phosphoglycerol and ornithine lipids. Major fatty acids are C-1(6:)1 omega 8+C-1(6:)1 omega 7 (34%), C-1(6:)1 omega 5 (16%), and C-18(:)1 omega 7 (11%). Optimum growth is observed at pH 8.0 and 25 degrees C. The DNA G+C content based on a draft genome sequence is 46.7 mol%. Phylogenetic analysis of 16S rRNA genes and a larger set of conserved genes place strain XLMV4(T) within the class Gammaproteobacteria and family Methylococcaceae, most closely related to members of the genera Methylomicrobium and Methylobacter (95.0-97.1% 16S rRNA gene sequence identity). In silico genomic predictions of DNA-DNA hybridization values of strain XLMV4(T) to the nearest phylogenetic neighbours were all below 26%. On the basis of the data presented, strain XLMV4(T) is considered to represent a new genus and species for which the name Methylicorpusculum oleiharenae is proposed. Strain XLMV4(T) (=DSMZ DSM 27269=ATCC TSD-186) is the type strain.