Thermobifida halotolerans sp. nov., isolated from a salt mine sample, and emended description of the genus Thermobifida

Abstract

The actinomycete strain YIM 90462T was isolated from a salt mine sample collected from Yunnan province, south-west China. Comparative 16S rRNA gene sequence analysis demonstrated that the isolate, which had sequence similarities of more than 97 % to Thermobifida alba, Thermobifida fusca and Thermobifida cellulosilytica, was a candidate member of the genus Thermobifida. Subsequently, a polyphasic approach was used to clarify the taxonomic position of strain YIM 90462 T . Its diagnostic diamino acid was meso-diaminopimelic acid and whole-cell sugars contained galactose, xylose and glucose. The predominant menaquinones were MK-10(H 6 ) and MK-10(H 8 ). The major fatty acids were iso-C 16 : 0 and anteiso-C 17 : 0 . Results of DNA-DNA hybridizations and physiological and biochemical tests enabled genotypic and phenotypic differentiation of strain YIM 90462 T from the three Thermobifida species with validly published names. Consequently, it is proposed that strain YIM 90462 T should be recognized as a representative of a novel species of Thermobifida, Thermobifida halotolerans sp. nov. The type strain is YIM 90462 T (5KCTC 19123 T 5DSM 44931 T ). In addition, an emended description of the genus Thermobifida is presented.The establishment of the genus Thermobifida (Zhang et al., 1998) was based on the reclassification of Thermobifida alba and Thermobifida fusca, which were formerly classified as Thermomonospora species (Cross & Goodfellow, 1973;McCarthy & Cross, 1984). Later, Thermobifida cellulosilytica was described by Kukolya et al. (2002). All three Thermobifida species were isolated from manure heaps, composts or damp stored hay and present outstanding cellulose decomposition abilities. T. fusca YX is used as a model organism for studies of aerobic, thermophilic, cellulolytic bacteria and a complete genome is also available for this strain (Wilson, 2004;Lykidis et al., 2007).Strain YIM 90462 T was isolated from a salt mine sample, collected from Yunnan province, south-west China, after 3 weeks incubation at 45 u C on modified ISP medium 4 containing 10 % NaCl (w/v). In view of its thermotolerant and halotolerant capabilities, this strain was studied further and its phylogenetic position was elucidated. Extraction of genomic DNA and amplification of the 16S rRNA gene were done as described by Li et al. (2007). The nearly complete 16S rRNA gene sequence of strain YIM 90462 T was determined and BLAST (Altschul et al., 1997) searches revealed that it possessed significant sequence similarities to those of Thermobifida species. Sequence similarities were determined by using CLUSTAL_X (Thompson et al., 1997

Macroamphiphilic Components of Thermophilic Actinomycetes: Identification of Lipoteichoic Acid in Thermobifida fusca

“…As expected, significant amounts of glycerol were detected, along with minor amounts of glucose (data not shown). The fatty acid composition of the whole bacterial cells was consistent with that reported previously for T. fusca (20,60); it was dominated by branched-chain saturated fatty acids, notably 14-methylpentadecanoate (iso- Cumulatively, these data suggested the presence of a PGP-LTA with a fatty acylated lipid anchor unit containing glucose (and possibly glucosyl substitution on the PGP polymer backbone). This material is referred to below as LTA Tf .…”

Taxonomy, Physiology, and Natural Products of Actinobacteria

“…More recently, Thermobifida halotolerans sp. nov. was proposed as representative of a novel species of Thermobifida (172). Members of the genus Thermobifida are Gram-positive, non-acid-fast, chemo-organotrophic aerobic organisms that form an extensively branched substrate mycelium.…”

A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET) and Polylactic Acid (PLA)

“…However, for industrial processes, more efficient enzymes are still needed while their potential to surface hydrophylize PLA has been largely neglected. In 2008, Thermobifida halotolerans has been isolated from a salt mine sample collected from Yunnan province (Southwest China, [43]) and classified as a novel species of Thermobifida. In order to identify homologous cutinases from this novel species, primers were designed, based on the genome sequences of cutinases from T. fusca YX.…”