Fermentibacillus polygoni gen. nov., sp. nov., an alkaliphile that reduces indigo dye

Abstract

Facultatively alkaliphilic strains, designated as strains IEB3 T and IEB14, were isolated as indigoreducing strains from a fermented Polygonum indigo (Polygonum tinctorium Lour) liquor sample prepared in our laboratory using a medium containing an indigo fermentation liquor as a sole substrate. The 16S rRNA gene sequence phylogeny and similarity suggested that strains IEB3 T and IEB14 exhibit distinctive positions among the members of the genus Bacillus, and their closest neighbour was Bacillus nanhaiisediminis NH3 T (similarity: 97.4 %) among the species with validly published names. The 16S rRNA sequence of strain IEB3 T was identical to that of strain IEB14. The cells of the isolates stained Gram-positive and were facultatively anaerobic, straight rods that were motile by a pair of subpolar flagella. Strains IEB3 T and IEB14 grew at temperatures between 12 and 40 C with optimum growth at 30--33 C and in the range of pH 7.5-12. Menaquinone-7 (MK-7) was detected as the major isoprenoid quinone. The DNA G +C contents of strains IEB3 T and IEB14 were 49.1 and 49.9 mol%, respectively. The whole-cell fatty acid profile mainly (>10 %) consisted of iso-C 14:0 , iso-C 15:0 and anteiso-C 15:0 . DNA-DNA hybridization revealed a low relatedness value between strain IEB3 T and the phylogenetically most closely related species, Bacillus nanhaiisediminis JCM 16507 T (<7 % ). On the basis of phenotypic and chemotaxonomic characteristics and phylogenetic data, the isolates represent a novel species within a novel genus, for which the name Fermentibacillus polygoni gen. nov., sp. nov. is proposed. The type strain is IEB3 T (=JCM 30817 T =NCIMB 14984 T ).Traditional indigo dyeing in Japan has been performed on the basis of the indigo-reducing ability of bacteria. Transitional changes in microbiota from the initiation of fermentation to the indigo-reducing state under alkaline conditions (higher than pH 10) have been observed (Aino et al., 2010). It has been considered that certain bacteria have the ability to reduce indigo and such bacteria contribute to the maintenance of the indigo-reducing state. We have isolated indigo-reducing bacteria, namely Alkalibacterium psychrotolerans, Alkalibacterium iburiense and Alkalibacterium indicireducens from indigo fermentation liquor obtained from Date City, Iburi, Hokkaido, and Tokushima City, Shikoku, in Japan (Nakajima et al., 2005; Yumoto et al., 2004Yumoto et al., , 2008. We have also isolated indigo-reducing bacteria belonging to the genus Amphibacillus, namely Amphibacillus indicireducens and Amphibacillus iburiensis (Hirota et al., 2013a, c). Furthermore, we have isolated Oceanobacillus indicireducens as an indigo-reducing bacterium (Hirota et al., 2013b). Surprisingly, although strains belonging to this genus possess isoprenoid quinone, this bacterium does not possess any isoprenoid quinone. The above reports suggest that numerous bacterial species contribute to indigo reduction in indigo fermentation liquor. There is a possibility that more diverse species are involved in indigo...

Microbial Communities Associated With Indigo Fermentation That Thrive in Anaerobic Alkaline Environments

“…Therefore, we considered these strains to represent a novel species within a novel genus, and the name Fermentibacillus polygoni gen. nov., sp. nov. was proposed for this species ( Hirota et al, 2016a ; Table 1 ). Although the isolates were obtained from IFLA medium, this species did not require indigo fermentation liquid for growth.…”

Mechanistic Insights into Indigo Reduction in Indigo Fermentation: A Voltammetric Study

“…A number of indigo-reducing microorganisms were isolated from fermentation vats [3][4][5][6][7][8][9][10][11][12][13][14][15] and several enzymes involved in indigo reduction, such as an azoreductase, were characterized. [16][17][18][19] However, little is known about the mechanism and the electron donor of the microbial indigo reduction as well as the significance of the alkali environment of the fermenting dye suspensions and the advantage of the addition of sake.…”

Characterization of the microbiota in long- and short-term natural indigo fermentation

“…There are ten named species within the genus Amphibacillus, and 2 of these species are indigo-reducing bacteria: Amphibacillus indicireducens [12] and Amphibacillus iburiensis [13]. In addition, some other species belonging to the class Bacilli, such as Oceanobacillus indicireducens [11], Fermentibacillus polygoni [14], Polygonibacillus indicireducens [17], Paralkalibacillus indicireducens [15], and Bacillus fermenti [16], have been shown to be indigoreducing bacteria in recent years.…”