Geobacillus gargensis sp. nov., a novel thermophile from a hot spring, and the reclassification of Bacillus vulcani as Geobacillus vulcani comb. nov.

Abstract

A novel thermophilic spore-forming strain, GaT, was isolated from the Garga hot spring located in the northern part of the Transbaikal region (Russia). Strain GaT was found to be an aerobic, Gram-positive, rod-shaped, thermophilic (optimum growth temperature is 60–65 °C), chemo-organotrophic bacterium that grows on various sugars, carboxylic acids and hydrocarbons. The G+C content of its DNA is 52·9 mol%. The 16S rRNA gene sequence similarity data show that strain GaT is closely related to members of the genus Geobacillus. Relevant chemotaxonomic data (in particular, the major fatty acid profile of strain GaT, which includes iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0 acids) support the assignment of this strain to the genus Geobacillus. The physiological, biochemical and DNA–DNA hybridization studies of strain GaT showed that it differs both genotypically and phenotypically from the recognized Geobacillus species. Based on these data, strain GaT belongs to a novel species, Geobacillus gargensis sp. nov. (type strain, GaT=VKM B-2300T=DSM 15378T). The analysis of the phenotypic characteristics (additional to those given in the original description) of the type strain of Bacillus vulcani (DSM 13174T) showed that they are very similar to the major phenotypic characteristics of the genus Geobacillus. The low DNA–DNA reassociation values of strain DSM 13174T with various species of this genus (from 38 to 54 %) clearly demonstrate a sufficient genomic distinction of this strain and its taxonomic status as a species. The physiological characteristics, phylogenetic position and DNA–DNA reassociation values of B. vulcani allow this species to be reclassified as Geobacillus vulcani comb. nov. The main properties that differentiate G. vulcani from the other species of the genus are its ability to produce acids from glycerol, lactose and ribose.

Application of a recN sequence similarity analysis to the identification of species within the bacterial genus Geobacillus

“…On the other hand, Geobacillus discovery programmes are uncovering novel isolates and spawning novel species proposals at a rapid rate Kuisiene et al, 2004;Nazina et al, 2004;Schäffer et al, 2004). Analysis of recN gene sequences, in combination with 16S rRNA sequence analysis, could provide a powerful, high-throughput tool for validating and maintaining the taxonomy of this genus.…”

Taxonomic revision of the genus Geobacillus : emendation of Geobacillus , G. stearothermophilus , G. jurassicus , G. toebii , G. thermodenitrificans

“…Nazina et al (2001) proposed that the six species of that lineage, namely B. stearothermophilus, B. kaustophilus, B. thermoglucosidasius, B. thermocatenulatus, B. thermoleovorans and B. thermodenitrificans, should be accommodated in a new genus, Geobacillus, along with two novel species, Geobacillus subterraneus and Geobacillus uzenensis. Subsequently, Bacillus pallidus (Scholz et al, 1987), Saccharococcus caldoxylosilyticus (Ahmad et al, 2000) and Bacillus vulcani (Caccamo et al, 2000) were transferred to Geobacillus (Fortina et al, 2001;Banat et al, 2004;Nazina et al, 2004) and then Miñana-Galbis et al (2010) proposed the further transfer of Geobacillus pallidus to the new genus Aeribacillus. Subsequently, six further species, Geobacillus toebii (Sung et al, 2002), G. gargensis (Nazina et al, 2004), G. debilis , G. lituanicus (Kuisiene et al, 2004), G. tepidamans (Schäffer et al, 2004) and G. jurassicus (Nazina et al, 2005) have been proposed and the names 'Geobacillus caldoproteolyticus' (Chen et al, 2004) and the subspecies 'G.…”

Physio-Biochemical Characterization and 16S rRNA Sequencing of Thermophilic Geobacillus sp. stain DB2 from Dibekli Hot Spring, Turkey

“…(-) (Nazina et al, 2001), 9: G. caldoxylosilyticus DSM 12041T (Fortina et al, 2001), 10: G. toebii DSM 13551 (Sung et al, 2002), 11: G. gargensis DSM 15378 ve 12: G. vulcani DSM 13174 (Nazina et al, 2004), 13: G. jurassicus DSM 15726T (Nazina et al, 2005), 14: G. debilis DSM 16016T ve 15: G. palidus (Banat et al, 2004), 16: G. lituanicus DSM 15325T (Kuisiene et al, 2004), 17: G. tepidamans (Schaffer et al, 2004), 18: G. thermoantarcticus DSM 9572T (Coorevits et al, 2012), 19: G. galactosidasius DSM 18751 (Poli et al, 2011), 20: G. icigianus (Bryanskaya et al, 2015) Türkiye'deki Dibekli Sıcak Su Kaynağından Termofilik Geobacillus sp. DB2 Suşunun Fizyo-Biyokimyasal Karakterizasyonu ve 16S rRNA Sekanslaması DB2 suşunun yapılan kısmi 16S rRNA sekans analizlerine göre Geobacillus türleri içinde %98.97 benzerlik oranıyla G. subterraneus subsp.…”

“…Ancak ilerleyen teknoloji ve moleküler düzeydeki gelişmiş teknikler sayesinde yeni tanımlamalar yapılmaktadır. Nazina et al, (2001) (Fortina et al, 2001), Geobacillus toebii DSM 13551 (Sung et al, 2002), Geobacillus gargensis DSM 15378 ve Geobacillus vulcani DSM 13174 (Nazina et al, 2004), Geobacillus debilis DSM 16016…”