Lactobacillus suntoryeus sp. nov., isolated from malt whisky distilleries

Abstract

Eight strains of Lactobacillus with identical partial 16S rRNA gene sequences and similar randomly amplified polymorphic DNA patterns were isolated from fermentation samples from Japanese and Scottish malt whisky distilleries. Phylogenetic analysis of almost complete 16S rRNA gene sequences from three representative strains (two from Japan, one from Scotland) placed them in the genus Lactobacillus as members of the Lactobacillus acidophilus group. Lactobacillus helveticus and Lactobacillus gallinarum were the most closely related species, with 16S rRNA gene similarities of 99?3 and 98?1 %, respectively. A similar phylogeny was derived from partial sequences of elongation factor Tu (tuf ) genes in which the alleles from the three distillery isolates were identical and shared 99?0 % similarity with L. helveticus and L. gallinarum tuf genes. S-layer (slp) gene sequences suggested different relationships among the strains and the distillery isolates no longer formed a monophyletic group. The alleles from the Japanese and Scottish strains shared only 54 % similarity. Chromosomal DNA from the distillery strains gave DNA-DNA hybridization values between 79 and 100 % but showed less than 43 and 22 % reassociation with L. helveticus and L. gallinarum DNA, respectively. The name Lactobacillus suntoryeus sp. nov. is proposed for this novel taxon; the type strain is strain SA T (=LMG 22464 T =NCIMB 14005 T ).Lactic acid bacteria comprise a natural component of the microflora of malt whisky fermentation (Simpson et al., 2001;van Beek & Priest, 2002). In well-maintained distilleries their numbers are low at the beginning of the fermentation, but, once the yeast has completed the alcoholic fermentation, they grow prolifically during the 'late lactic fermentation' and are considered to confer positive flavour notes to the spirit (Takatani & Ikemoto, 2004). The most common species encountered are Lactobacillus brevis, Lactobacillus fermentum and Lactobacillus paracasei, but numerous other Lactobacillus species, lactococci, leuconostocs and weissellas have been detected, particularly in the early stages of the fermentation, when the alcohol concentration is relatively low (van Beek & Priest, 2003).Analysis of Scotch whisky fermentations using denaturing gradient gel electrophoresis revealed an uncultured bacterium in the late stages of fermentation that was closely related to a bacterium isolated from a Japanese malt whisky fermentation and referred to as strain Y10. Phylogenetic studies based on the 16S rRNA gene sequence of strain Y10 suggested that this bacterium was a member of the Lactobacillus acidophilus group (van Beek & Priest, 2002). This group comprises L. acidophilus sensu stricto, Lactobacillus amylovorus, Lactobacillus crispatus, Lactobacillus gallinarum, Lactobacillus gasseri, Lactobacillus helveticus and Lactobacillus johnsonii (Johnson et al., 1980;Fujisawa et al., 1992;Gancheva et al., 1999), with three relatively recent additions: Lactobacillus amylolyticus, isolated from malt and beer wort (Bohak et al., 1998)...

Application of molecular identification tools for Lactobacillus, with a focus on discrimination between closely related species: A review

“…However, the tuf gene sequence analysis was found inadequate for strain level typing. In another study conducted by Cachat and Priest (2005) the phylogenetic evaluation of three malt whisky distillery isolates belonging to the newly isolated Lactobacillus species L. syntoryeus, based on tuf gene sequence comparisons, was found highly in accordance with partial 16S rRNA profiles and RAPD patterns.…”

Lactobacillus surface layer proteins: structure, function and applications

“…However, when the phylogenetic trees constructed on the basis of the S-layer protein genes of a set of L. acidophilus -related organisms, including strains of the novel Lactobacillus suntoryeus species [later reclassified as L. helveticus (Naser et al 2006)], were compared with trees constructed on the basis of 16S rRNA or elongation factor Tu ( tuf ) gene sequences of the same species, the novel strains grouped together in the latter tree, but not in the former tree based on the S-layer protein genes. This indicates a strong selective pressure driving the diversification of S-layer protein genes within at least some L. acidophilus -related organisms as well (Cachat and Priest 2005). Nevertheless, the remarkable similarities on the amino acid level between the S-layer proteins of L. acidophilus -related organisms have led to the proposal of using LC-MS/MS analysis of S-layer proteins for typing strains within this group (Podlesny et al 2011).…”

Evaluation of the microbial community in industrial rye sourdough upon continuous back-slopping propagation revealed Lactobacillus helveticus as the dominant species

“…BLAST analysis of partial 16S rRNA gene sequences of isolates N92, E96 and N720 (GenBank ID: HM641233, HM623785 and HM641232, respectively) first determined Lactobacillus suntoryeus as the closest match (data not shown). Lactobacillus suntoryeus is a recently identified species (Cachat and Priest 2005), which afterwards was claimed to be a later synonym of Lact. helveticus (Naser et al 2006).…”