Methylocystis suflitae sp. nov., a novel type II methanotrophic bacterium isolated from landfill cover soil

Abstract

A bacterial strain, designated NLS-7T, was isolated through enrichment of landfill cover soil in methane-oxidizing conditions. Strain NLS-7T is a Gram-stain negative, non-motile rod, approximately 0.8 µm wide by 1.3 µm long. Phylogenetic analysis based on 16S rRNA gene sequencing places it within the genus Methylocystis , with its closest relatives being M. hirsuta , M. silviterrae and M. rosea , with 99.9, 99.7 and 99.6 % sequence similarity respectively. However, average nucleotide identity and average amino acid identity values below the 95 % threshold compared to all the close relatives and digital DNA–DNA hybridization values between 20.9 and 54.1 % demonstrate that strain NLS-7T represents a novel species. Genome sequencing generated 4.31 million reads and genome assembly resulted in the generation of 244 contigs with a total assembly length of 3 820 957 bp (N50, 37 735 bp; L50, 34). Genome completeness is 99.5 % with 3.98 % contamination. It is capable of growth on methane and methanol. It grows optimally at 30 °C between pH 6.5 and 7.0. Strain NLS-7T is capable of atmospheric dinitrogen fixation and can use ammonium (as NH4Cl), l-aspartate, l-arginine, yeast extract, nitrate, l-leucine, l-proline, l-methionine, l-lysine and l-alanine as nitrogen sources. The major fatty acids are C18:1 ω8c and C18:1 ω7c. Based upon this polyphasic taxonomic study, strain NLS-7T represents a novel species of the genus Methylocystis , for which the name Methylocystis suflitae sp. nov. is proposed. The type strain is NLS-7T (=ATCC TSD-256T=DSM 112294T). The 16S rRNA gene and genome sequences of strain NLS-7T have been deposited in GenBank under accession numbers ON715489 and GCA_024448135.1, respectively.