Isolation and Characteristics of Lactic Acid Bacteria in Japanese Spirit Awamori Mash

Lactic acid bacteria were isolated from commercial awamori mashes from Okinawa and small-scale brewing in a laboratory. The commercial awamori mash and the awamori mash from small-scale brewing in a laboratory were fermented completely. The alcohol concentration of commercial awamori mash was 19.5% (vol/vol), and its acidity was 9.8 mL. The alcohol concentration in the awamori mash from small-scale brewing in a laboratory was 18.3% (vol/vol); its titratable acidity was 14 mL. At the first stage of fermentation, 106 CFU of lactic acid bacteria per g of mash was detected; 102 CFU of lactic acid bacteria per g of mash was detected at the midstage. At the final stage, lactic acid bacteria were not detected. The bacteria were identified using morphological and molecular biological methods as Leuconostoc mesenteroides, Lactobacillus plantarum, and Lactobacillus casei. They did not require mevalonic acid, were alcohol and low-pH tolerant, and were able to grow in awamori mash with high alcohol and citric acid contents. It is thought that these lactic acid bacteria were not contaminant bacteria of awamori mash, but that they might affect yeast growth, flavor formation, and alcohol production during fermentation of awamori mash.