Isolation of the Alcohol-Tolerant Lactic Acid Bacteria Pediococcus acidilactici K3 and S1 and their Physiological Characterization.

摘要

Lactic acid bacteria (LAB) are a representative group of probiotics and used in many fermented foods and beverages. Several recent studies have shown that LAB are present in makgeolli which is a traditional Korean alcoholic beverage. However, most LABare intolerant of more than 6% (v/v) alcohol concentrations. For this reason, alcohol-tolerant LAB are isolated from kimchi, makgeolli and nuruk using alcohol containing selective media. After being cultured in MRS broth containing 13% (v/v) alcohol, the two strains which showed the highest increasing O.D values, were finally selected. As results of 16S rRNA gene sequencing and biochemical characterization using an API kit, the two species were identified as Pediococcus acidilactici K3 and S1. In addition, the identified two strains produced bacteriocins against Staphylococcus aureus. When compared with the P. acidilactici type strain, the two selected strains possessed two to three time higher growth on 12-13% (v/v) alcohol containing MRS broth. Theviability of P. acidilactici K3 and S1 when inoculated in makgeolli and stored at 10°C did not decrease through a period of one month indicating that the selected strains can be used for LAB containing makgeolli.