Laceyella sediminis

Abstract: The family Thermoactinomycetaceae comprises 43 validly published species, which were identified by a polyphasic taxonomic study based on molecular phylogenetics, physiological and biochemical characteristics. However, phylogenetic analysis merely based on 16S rRNA gene sequences cannot infer a robust and reliable phylogeny. For disentangling the phylogenetic relationships among members of this family, we used a large collection of genome data and the approach of phylogenomics, to re-examine their taxonomy. The topologies of phylogenomic trees are different from those of the 16S rRNA gene sequences. In addition, based on the average nucleotide identity, digital DNA–DNA hybridization, phenotypic and biochemical characteristics, we found that Laceyella sediminis should be reclassified as a later heterotypic synonym of Laceyella tengchongensis ; and reclassified Thermoactinomyces guangxiensis as Paenactinomyces guangxiensis gen. nov., comb. nov.; and establish Novibacillaceae fam. nov. to accommodate the genus Novibacillus as the type genus. In addition, compared to values calculated directly from genome sequences, the genomic DNA G+C contents mentioned in some species descriptions are too imprecise; and the corrected G+C content values have a significantly better fit to the phylogeny. Thus, the corresponding emendations of species descriptions are also proposed. In this paper, phylogenomics has been used to resolve the classification of the family Thermoactinomycetaceae .

Abstract: Moutai-flavour Daqu is an important starter to support growth of microorganisms in the fermented process of Moutai-flavour liquor. A novel thermophilic microorganism, designated strain FBKL4.011T, was isolated from Moutai-flavour Daqu samples collected from Guotai distillery in Renhuai, Guizhou province, south-west China. The strain could grow at 45–65 °C (optimum 45 °C). Based on polyphasic analysis, strain FBKL4.011T was affiliated to the genus Thermoflavimicrobium . It formed abundant pale-yellow aerial and substrate mycelium, bearing single endospores (7.0–10.0 µm diameter) on branched long sporophores (5.0 µm diameter). The cell-wall peptidoglycan contained meso-diaminopimelic acid; ribose, glucose and mannose were the primary whole-cell sugars. The major fatty acids were iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. The predominant menaquinone were MK-8 and MK-9. The polar phospholipids contained diphosphatidyl glycerol, phosphatidyl ethanolamine, one unidentified phospholipid and one unidentified lipid. The G+C content of the genome was 43.1 mol%. According to the 16S rRNA gene sequence analysis, strain FBKL4.011T was closely related to Thermoflavimicrobium dichotomicum JCM 9688T (95.3 % sequence similarity), and other members within the family Thermoactinomycetaceae (less than 93.0 % sequence similarity). The DNA–DNA hybridisation data showed low relatedness between strain FBKL4.011T and T. dichotomicum JCM 9688T, Laceyella sacchari KCTC 9790T, Laceyella tengchongensis YIM 10002T, Laceyella sediminis RHA1T(36.7±1.1 %, 30.0±1.2 %, 21.3±2.1 % % and 37.6±0.9 %, respectively). Based on data from the polyphasic analysis, strain FBKL4.011T is considered to represent a novel species of the genus Thermoflavimicrobium , for which the name Thermoflavimicrobium daqui sp. nov. is proposed. The type strain is FBKL4.011T(=KCTC 43036T=CICC 24504T).

Abstract: A thermophilic bacterium, designated strain RHA1T, was isolated from a sediment sample collected from a hot spring in Tengchong county, Yunnan province, south-west China, and was characterized by using a polyphasic approach. Based on its phenotypic and phylogenetic characteristics, strain RHA1T was affiliated to the genus Laceyella. The strain formed white aerial and yellow–white substrate mycelia, bearing single endospores on short sporophores. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Whole-cell hydrolysates contained ribose and glucose. The major fatty acids were iso-C15 : 0 (62.39 %) and anteiso-C15 : 0 (17.55 %). The predominant menaquinone was MK-9. The G+C content of the genomic DNA of strain RHA1T was 47.9 mol%. Based on DNA–DNA hybridization data, chemotaxonomic characteristics and differential physiological properties, strain RHA1T is considered to represent a novel species of the genus Laceyella, for which the name Laceyella sediminis sp. nov. is proposed; the type strain is RHA1T ( = DSM 45263T = CCTCC AA 208058T).