Tikhonova Ekaterina N, Suleimanov Ruslan Z, Miroshnikov Kirill K, Oshkin Igor Y, Belova Svetlana E, Danilova Olga V, Ashikhmin Aleksandr A, Konopkin Aleksey A, But Sergey Y, Khmelenina Valentina N, Pimenov Nikolai V, Dedysh Svetlana N
Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia.
Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Syst Appl Microbiol. 2023 Apr;46(2):126398. doi: 10.1016/j.syapm.2023.126398. Epub 2023 Jan 24.
The genus Methylomonas accommodates strictly aerobic, obligate methanotrophs, with their sole carbon and energy sources restricted to methane and methanol. These bacteria inhabit oxic-anoxic interfaces of various freshwater habitats and have attracted considerable attention as potential producers of a single-cell protein. Here, we characterize two fast-growing representatives of this genus, strains 12 and MP1, which are phylogenetically distinct from the currently described Methylomonas species (94.0-97.3 % 16S rRNA gene sequence similarity). Strains 12 and MP1 were isolated from freshwater sediments collected in Moscow and Krasnodar regions, respectively. Cells of these strains are Gram-negative, red-pigmented, highly motile thick rods that contain a type I intracytoplasmic membrane system and possess a particulate methane monooxygenase (pMMO) enzyme. These bacteria grow between 8 and 45 °C (optimum 35 °C) in a relatively narrow pH range of 5.5-7.3 (optimum pH 6.6-7.2). Major carotenoids synthesized by these methanotrophs are 4,4'-diaplycopene-4,4'-dioic acid, 1,1'-dihydroxy-3,4-didehydrolycopene and 4,4'-diaplycopenoic acid. High biomass yield, of up to 3.26 g CDW/l, is obtained during continuous cultivation of MP1 on natural gas in a bioreactor at a dilution rate of 0.22 h. The complete genome sequence of strain MP1 is 4.59 Mb in size; the DNA G + C content is 52.8 mol%. The genome encodes four rRNA operons, one pMMO operon and 4,216 proteins. The genome sequence displays 82-85 % average nucleotide identity to those of earlier described Methylomonas species. We propose to classify these bacteria as representing a novel species of the genus Methylomonas, M. rapida sp. nov., with the type strain MP1 (=KCTC 92586 = VKM B-3663).
甲基单胞菌属包含严格需氧的专性甲烷氧化菌，其唯一的碳源和能源仅限于甲烷和甲醇。这些细菌栖息于各种淡水生境的有氧 - 缺氧界面，作为单细胞蛋白的潜在生产者已引起了相当大的关注。在此，我们对该属的两个快速生长代表菌株12和MP1进行了表征，它们在系统发育上与目前已描述的甲基单胞菌属物种不同（16S rRNA基因序列相似性为94.0 - 97.3%）。菌株12和MP1分别从莫斯科和克拉斯诺达尔地区采集的淡水沉积物中分离得到。这些菌株的细胞为革兰氏阴性、红色色素沉着、高度运动的粗杆状，含有I型胞内膜系统，并拥有颗粒状甲烷单加氧酶（pMMO）。这些细菌在8至45°C（最适温度35°C）、相对较窄的pH范围5.5 - 7.3（最适pH 6.6 - 7.2）内生长。这些甲烷氧化菌合成的主要类胡萝卜素为4,4'-二脱水番茄红素-4,4'-二酸、1,1'-二羟基-3,4-二脱氢番茄红素和4,4'-二脱水番茄红素酸。在生物反应器中以0.22 h的稀释率用天然气对MP1进行连续培养时，可获得高达3.26 g CDW/l的高生物量产量。菌株MP1的完整基因组序列大小为4.59 Mb；DNA的G + C含量为52.8 mol%。该基因组编码四个rRNA操纵子、一个pMMO操纵子和4216种蛋白质。该基因组序列与早期描述的甲基单胞菌属物种的基因组序列平均核苷酸同一性为82 - 85%。我们提议将这些细菌分类为代表甲基单胞菌属的一个新物种，即快速甲基单胞菌（Methylomonas rapida sp. nov.），模式菌株为MP1（=KCTC 92586 = VKM B - 3663）。
