Vulcaniibacterium gelatinicum sp. nov., a moderately thermophilic bacterium isolated from a hot spring

Int J Syst Evol Microbiol. 2020 Mar;70(3):1571-1577. doi: 10.1099/ijsem.0.003934.


The present study aimed to determine the taxonomic positions of strains designated R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 isolated from hot spring water samples. Cells of these strains were Gram-stain-negative, non-motile and rod-shaped. The strains shared highest 16S rRNA gene sequence similarity with Vulcaniibacterium thermophilum KCTC 32020T (95.1%). Growth occurred at 28-55 °C, at pH 6-8 and with up to 3 % (w/v) NaCl. DNA fingerprinting, biochemical, phylogenetic and 16S rRNA gene sequence analyses suggested that R-5-52-3T, R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were different strains but belonged to the same species. Hence, R-5-52-3T was chosen for further analysis and R-5-33-5-1-2, R-5-48-2 and R-5-51-4 were considered as additional strains of this species. R-5-52-3T possessed Q-8 as the only quinone and iso-C15:0, iso-C11:0, C16 : 0 and iso-C17 : 0 as major fatty acids. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified polar lipids and two unidentified phospholipids. The genomic G+C content was 71.6 mol%. Heat shock proteins (e.g. Hsp20, GroEL, DnaK and Clp ATPases) were noted in the R-5-52-3T genome, which could suggest its protection in the hot spring environment. Pan-genome analysis showed the number of singleton gene clusters among Vulcaniibacterium members varied. Average nucleotide identity (ANI) values between R-5-52-3T, Vulcaniibacterium tengchongense YIM 77520T and V. thermophilum KCTC 32020T were 80.1-85.8 %, which were below the cut-off level (95-96 %) recommended as the ANI criterion for interspecies identity. Thus, based on the above results, strain R-5-52-3T represents a novel species of the genus Vulcaniibacterium, for which the name Vulcaniibacterium gelatinicum sp. nov. is proposed. The type strain is R-5-52-3T (=KCTC 72061T=CGMCC 1.16678T).

Keywords: Proteobacteria; Vulcaniibacterium gelatinicum; gelatin degradation; hot spring; moderate thermophile.

MeSH terms

  • Bacterial Typing Techniques
  • Base Composition
  • DNA, Bacterial / genetics
  • Fatty Acids / chemistry
  • Genes, Bacterial
  • Hot Springs / microbiology*
  • Phospholipids / chemistry
  • Phylogeny*
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Ubiquinone / chemistry
  • Water Microbiology
  • Xanthomonadaceae / classification*
  • Xanthomonadaceae / isolation & purification


  • DNA, Bacterial
  • Fatty Acids
  • Phospholipids
  • RNA, Ribosomal, 16S
  • Ubiquinone
  • ubiquinone 8