Methylococcus geothermalis sp. nov., a methanotroph isolated from a geothermal field in the Republic of Korea

Abstract

A Gram-stain-negative, aerobic, non-motile and coccoid methanotroph, strain IM1T, was isolated from hot spring soil. Cells of strain IM1T were catalase-negative, oxidase-positive and displayed a characteristic intracytoplasmic membrane arrangement of type I methanotrophs. The strain possessed genes encoding both membrane-bound and soluble methane monooxygenases and grew only on methane or methanol. The strain was capable of growth at temperatures between 15 and 48 °C (optimum, 30–45 °C) and pH values between pH 4.8 and 8.2 (optimum, pH 6.2–7.0). Based on phylogenetic analysis of 16S rRNA gene and PmoA sequences, strain IM1T was demonstrated to be affiliated to the genus Methylococcus . The 16S rRNA gene sequence of this strain was most closely related to the sequences of an uncultured bacterium clone FD09 (100 %) and a partially described cultured Methylococcus sp. GDS2.4 (99.78 %). The most closely related taxonomically described strains were Methylococcus capsulatus TexasT (97.92 %), Methylococcus capsulatus Bath (97.86 %) and Methyloterricola oryzae 73aT (94.21 %). Strain IM1T shared average nucleotide identity values of 85.93 and 85.62 % with Methylococcus capsulatus strains TexasT and Bath, respectively. The digital DNA–DNA hybridization value with the closest type strain was 29.90 %. The DNA G+C content of strain IM1T was 63.3 mol% and the major cellular fatty acids were C16 : 0 (39.0 %), C16 : 1 ω7c (24.0 %), C16 : 1 ω6c (13.6 %) and C16 : 1 ω5c (12.0 %). The major ubiquinone was methylene-ubiquinone-8. On the basis of phenotypic, genetic and phylogenetic data, strain IM1T represents a novel species of the genus Methylococcus for which the name Methylococcus geothermalis sp. nov. is proposed, with strain IM1T (=JCM 33941T=KCTC 72677T) as the type strain.

Metabolism Interactions Promote the Overall Functioning of the Episymbiotic Chemosynthetic Community of Shinkaia crosnieri of Cold Seeps

“…These genes were colocalized, consistent with their presence in other Methylococcales genomes ( Fig. S5 ), while also exhibiting close identity to genes within other methylotrophic bacterial genomes ( 60 ). Consequently, the SOX complexes in the methylotrophic MAGs are not likely data analysis artifacts.…”

Expanding Characterized Diversity and the Pool of Complete Genome Sequences of Methylococcus Species, the Bacteria of High Environmental and Biotechnological Relevance

“…This is suggested by the results of phylogenomic analysis, comparative genome analysis as well as by the phenotypic difference of strain Mc7 and two previously described Methylococcus species. Thus, cells of strain Mc7 (~1.6 μm in diameter) were larger that cells of M. capsulatus (1.0-1.1 μm) or M. geothermalis (0.7-1.0 μm; Awala et al, 2020). The genome size of strain Mc7 (4.0 Mb) also exceeded that in other described Methylococcus species.…”

“…Apparently, all Methylococcus species are difficult to preserve (Bowman, 2015), which is the main reason behind poor availability of these bacteria from both public and laboratory culture collections. Recently described Methylococcus geothermalis (Awala et al, 2020) is the second described species of the genus, which is currently available in culture besides M. capsulatus.…”

Complete Genome Sequences of Two Gammaproteobacterial Methanotrophs Isolated from a Mercury-Contaminated Stream

“…LW13 ( 14 ), and Methylococcus sp. strain EFPC2 was most similar to Methylococcus geothermalis IM1 T ( 15 ). Average nucleotide identity (ANI) values between Methylomonas sp.…”