Bacillus fermenti sp. nov., an indigo-reducing obligate alkaliphile isolated from indigo fermentation liquor for dyeing

Int J Syst Evol Microbiol. 2018 Apr;68(4):1123-1129. doi: 10.1099/ijsem.0.002636. Epub 2018 Feb 16.


The indigo-reducing, facultatively anaerobic and obligately alkaliphilic strains Bf-1T, Bf-2 and Bf-4 were isolated from an indigo fermentation liquor used for dyeing, which uses sukumo [composted Polygonum indigo (Polygonum tinctorium Lour.) leaves] as a basic ingredient and was obtained from a craft centre in Date City, Hokkaido, Japan. The 16S rRNA gene sequence analyses indicated that the closest neighbours of strain Bf-1T are Bacillus maritimus DSM 100413T (98.3 % 16S rRNA gene sequence similarity), Bacillus persicus DSM 25386T (98.2 %) and Bacillus rigiliprofundi LMG 28275T (97.7 %). The 16S rRNA gene sequence of strain Bf-1T was almost identical to the sequences of strains Bf-2 and Bf-4 (99.9 %). Cells of strain Bf-1T stained Gram-positive and formed straight rods that achieved motility through a pair of subpolar flagella. Strain Bf-1T grew at temperatures of between 15 and 45 °C with optimum growth at 33‒40 °C. The strain grew in the pH range of pH 8‒12, with optimum growth at pH 10. The isoprenoid quinone detected was menaquinone-7 (MK-7), and the DNA G+C content was 41.7 %. The whole-cell fatty acid profile mainly (>10 %) consisted of iso-C15 : 0 and iso-C16 : 0. Phylogenetically related neighbours, although demonstrating high 16S rRNA gene sequence similarity (>97.6 %) with strain Bf-1T, exhibited less than 9 % relatedness in DNA-DNA hybridization experiments. Based on evidence from this polyphasic study, the isolates represent a novel species, for which the name Bacillus fermenti sp. nov. is proposed. The type strain of this species is Bf-1T (=JCM 31807T=NCIMB 15079T).

Keywords: Bacillus fermenti; alkaliphilic; indigo fermentation liquor; indigo reduction.

MeSH terms

  • Bacillus / classification*
  • Bacillus / genetics
  • Bacillus / isolation & purification
  • Bacterial Typing Techniques
  • Base Composition
  • Coloring Agents*
  • DNA, Bacterial / genetics
  • Fatty Acids / chemistry
  • Fermentation*
  • Indigo Carmine / analysis
  • Japan
  • Nucleic Acid Hybridization
  • Phylogeny*
  • Polygonum / microbiology*
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Vitamin K 2 / analogs & derivatives
  • Vitamin K 2 / chemistry


  • Coloring Agents
  • DNA, Bacterial
  • Fatty Acids
  • RNA, Ribosomal, 16S
  • Vitamin K 2
  • menaquinone 7
  • Indigo Carmine