title: Descriptions of Roseiarcus fermentans gen. nov., sp. nov., a bacteriochlorophyll a-containing fermentative bacterium related phylogenetically to alphaproteobacterial methanotrophs, and of the family Roseiarcaceae fam. nov.
abstract: A light-pink-pigmented, microaerophilic bacterium was obtained from a methanotrophic consortium enriched from acidic Sphagnum peat and designated strain Pf56(T). Cells of this bacterium were Gram-negative, non-motile, thick curved rods that contained a vesicular intracytoplasmic membrane system characteristic of some purple non-sulfur alphaproteobacteria. The absorption spectrum of acetone/methanol extracts of cells grown in the light showed maxima at 363, 475, 505, 601 and 770 nm; the peaks at 363 and 770 nm are characteristic of bacteriochlorophyll a. However, in contrast to purple non-sulfur bacteria, strain Pf56(T) was unable to grow phototrophically under anoxic conditions in the light. Best growth occurred on some sugars and organic acids under micro-oxic conditions by means of fermentation. The fermentation products were propionate, acetate and hydrogen. Slow chemo-organotrophic growth was also observed under fully oxic conditions. Light stimulated growth. C1 substrates were not utilized. Strain Pf56(T) grew at pH 4.0-7.0 (optimum pH 5.5-6.5) and at 15-30 °C (optimum 22-28 °C). The major cellular fatty acids were 19 : 0 cyclo ω8c and 18 : 1ω7c; quinones were represented by ubiquinone Q-10. The G+C content of the DNA was 70.0 mol%. Strain Pf56 displays 93.6-94.7 and 92.7-93.7% 16S rRNA gene sequence similarity to members of the families Methylocystaceae and Beijerinckiaceae, respectively, and belongs to a large cluster of environmental sequences retrieved from various wetlands and forest soils in cultivation-independent studies. Phenotypic, genotypic and chemotaxonomic characteristics of strain Pf56(T) suggest that it represents a novel genus and species of bacteriochlorophyll a-containing fermentative bacteria, for which the name Roseiarcus fermentans gen. nov., sp. nov. is proposed. Strain Pf56(T) ( = DSM 24875(T) = VKM B-2876(T)) is the type strain of Roseiarcus fermentans, and is also the first characterized member of a novel family within the class Alphaproteobacteria, Roseiarcaceae fam. nov.
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Irina S
authors.initials: IS
authors.lastname: Kulichevskaya
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Danilova
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Vera M
authors.initials: VM
authors.lastname: Tereshina
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Kevbrin
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dedysh
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D025541:Bacteriochlorophyll A / Q000737:chemistry; D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry; D008969:Molecular Sequence Data; D010802:Phylogeny; D010858:Pigmentation; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D017422:Sequence Analysis, DNA; D044003:Sphagnopsida / Q000382:microbiology*; D014451:Ubiquinone / Q000737:chemistry; D053833:Wetlands
chemical_list: D025541:Bacteriochlorophyll A; D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D014451:Ubiquinone; C025204:Ubiquinone Q2