Thermosporothrix hazakensis gen. nov., sp. nov., isolated from compost, description of Thermosporotrichaceae fam. nov. within the class Ktedonobacteria Cavaletti et al. 2007 and emended description of the class Ktedonobacteria

Abstract

We isolated from compost an aerobic, thermophilic, Gram-stain-positive, spore-forming bacterium that formed branched vegetative and aerial mycelia. This strain, designated SK20-1T, grew at 31–58 °C, with optimum growth at 50 °C, while no growth was observed below 28 or above 60 °C. The pH range for growth was 5.4–8.7, with optimum growth at pH 7.0, while no growth was observed below pH 5.0 or above pH 9.1. Strain SK20-1T was able to hydrolyse polysaccharides such as cellulose, xylan and chitin. The DNA G+C content was 54.0 mol%. The major fatty acid was iso-C17 : 0 and the major menaquinone was MK-9(H2). The cell wall contained glutamic acid, serine, alanine and ornithine in a molar ratio of 1.00 : 1.07 : 2.64 : 0.83. The polar lipids consisted of phosphatidylinositol, phosphatidylinositol mannosides, phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid. Cell-wall sugars were rhamnose and mannose. Detailed phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SK20-1T belongs to the class Ktedonobacteria, and that the strain is most closely related to Ktedonobacter racemifer SOSP1-21T (88.5 %). On the basis of its phenotypic features and phylogenetic position, we propose that SK20-1T represents a novel genus and species, Thermosporothrix hazakensis gen. nov., sp. nov., within the new family Thermosporotrichaceae fam. nov. The type strain of Thermosporothrix hazakensis is strain SK20-1T (=JCM 16142T =ATCC BAA-1881T). In addition, we propose an emended description of the class Ktedonobacteria to classify the class in the phylum Chloroflexi.

A life cycle of branched aerial mycelium- and multiple budding spore-forming bacterium Thermosporothrix hazakensis belonging to the phylum Chloroflexi

“…The aerial mycelia of strain SK20-1 T budded more spores after an incubation of over 7 days. The morphology of strain SK20-1 T at this stage was described previously (Yabe et al, 2009a). At this stage, there was infrequent spore germination or secondary sporulation from spores attached to aerial mycelia (Fig.…”

“…The closest relative of strain SK20-1 T with a validly published name is Ktedonobacter racemifer (Cavaletti et al, 2006) (88.5% sequence similarity). We have separately described the details of the taxonomic position of strain SK20-1 T (Yabe et al, 2009a). All species belonging to the phylum Chlorofl exi described so far do not form spores and branched mycelia, except K. racemifer described by Cavaletti et al (2006).…”

“…Thermosporothrix hazakensis strain SK20-1 T was isolated from compost by incubation at 50 C on plates (Yabe et al, 2009a). The compost was produced by a fi eld-scale composter, which had been used for treatment of livestock excrement.…”

Syntrophomonadaceae-Affiliated Species as Active Butyrate-Utilizing Syntrophs in Paddy Field Soil

“…S1 in the supplemental material) revealed that the 187-bp T-RF and the 394-bp T-RF significantly increased with the BD of DNA, reaching 59% and 28% of the community, respectively, at a BD of 1.590 g ml Ϫ1 . These T-RFs represented Methanosarcinaceae and Methanocellales, respectively, according to our previous studies in the same soil (19,25,26,29). Apparently, these organisms served as acetate and H 2 scavengers during the syntrophic oxidation of butyrate in the soil.…”

“…It has been shown, however, that some of the Anaerolineae within the Chloroflexi (Fig. S3) fermented various sugars and grew better in the presence of H 2 -consuming methanogens, hinting at a syntrophic metabolism (26,27). Alternatively, it is possible that Chloroflexi and Planctomycetes assimilated […”