Methylomonas montana sp. nov., the First Nonpigmented Methanotroph of the Genus Methylomonas, Isolated from Mountain River Sediments

• Published in: Microbiology (New York) 2023-12, Vol.92 (6), p.766-774
• Main Authors: Suleimanov, R. Z., Tikhonova, E. N., Oshkin, I. Y., Danilova, O. V., Dedysh, S. N.
• Format: Article
• Language: English
• Subjects: Bacteria; Biomedical and Life Sciences; Experimental Articles; Genomes; Leukocytes (neutrophilic); Life Sciences; Medical Microbiology; Methane monooxygenase; Methanotrophic bacteria; Microbiology; New species; Nucleotide sequence; Operons; Phylogeny; Pigmentation; Rivers; rRNA 16S; Sediments; Soluble methane monooxygenase
• ISSN: 0026-2617; 1608-3237
• DOI: 10.1134/S0026261723602324

— Aerobic methanotrophic bacteria of the genus Methylomonas inhabit a wide spectrum of habitats, including freshwater bodies, river sediments, wetlands, rice paddies, landfill cover soils, and hydromorphic soils. Majority of the currently described species of this genus are represented by neutrophilic, motile, growing on methane rod-shaped bacteria, whose pigmentation varies from yellow to pink and red. This study reports characterization of a novel, nonpigmented isolate of these bacteria, strain MW1 T , which was obtained from sediments of the mountain river Khosta, Krasnodar krai, Russia. Strain MW1 T grew on methane and methanol within a temperature range of 8–37°C (optimum at 25–30°C) and at рH 5.5–7.5 (optimum at 6.3–7.0). The 16S rRNA gene sequence of strain MW1 T displayed 95.48–98.47% similarity to those in earlier described Methylomonas species. The closest taxonomically characterized phylogenetic relative of strain MW1 T was M. fluvii EbB T , isolated from the river Elbe sediments. Complete genome sequence of strain MW1 T was 4.6 Mb in size and contained three rRNA operons and about 4200 protein-encoding genes, including the gene cluster pmoCAB coding for particulate methane monooxygenase. Soluble methane monooxygenase was not encoded in the genome. The G+C DNA content was 52.4%. The average nucleotide identity of the genome of strain MW1 T and the genomes of earlier described representatives of the genus Methylomonas was 79.4–82.1%. We propose to classify this isolate as representing a novel species of the genus Methylomonas , M. montana sp. nov. Strain MW1 T (=VKM 3737 T = UQM 41536 T ) is the type strain of the newly proposed species.