Yuki Asakawa (1),
Masayuki Aizawa (1), Kazumaru Iijima (1), Yasuo Motoyama (1), Satoshi
Shimotsu (1), Koji Suzuki (1); (1) Asahi Breweries, Ltd., Moriya-Shi,
Japan
Yeast, Fermentation, and Microbiology
Poster
Only a few microbial species can spoil beer because the growth of
microorganisms is inhibited by several factors in beer. The genus Lactobacillus is known as a predominant beer spoiler. In this study, Lactobacillus
sp. ABBC641, isolated from beer and originally deposited to VTT culture
collection, exhibited beer-spoilage ability by spoiling several
pilsner-type beers within the range of pH 4.1-4.6 and 10-20 bitterness
units. A PCR study also showed that the strain carries hop resistance
genes, horA and horC. Since these data indicate that
ABBC641 is a potential beer spoiler, further identification and
taxonomic studies were conducted. The complete 16S rRNA gene sequence
analysis showed that ABBC641 is closely related to Lactobacillus rossiae and Lactobacillus siliginis
with 97% similarity to each type strain, while it is generally
considered that over 98.7% similarity to the type strain is necessary to
be identified as the same species. In addition, the DNA–DNA
hybridization result indicated that the type strains of L. rossiae and L. siliginis exhibited 4% and 12% relatedness to ABBC641, respectively, suggesting that ABBC641 belongs to neither L. rossiae nor L. siliginis. Furthermore the carbohydrate fermentation profile of ABBC641 was slightly different from those of L. rossiae and L. siliginis. Taken collectively, these results revealed that ABBC641 belongs to a novel Lactobacillus species.
Yuki Asakawa received a master’s degree in engineering from the
Tokyo Institute of Technology, Japan, in March 2013 and joined Asahi
Breweries Ltd. She has been working on microbiological quality assurance
of alcohol beverages and developing microbiological quality control
test method for breweries in the Department of Fermentation and
Microbiology Technology of Research Laboratories for Alcoholic
Beverages.
