CHARACTERIZATION AND IDENTIFICATION OF LACTOBACILLUS-PENTOSUS AND LACTOBACILLUS-PLANTARUM STRAINS FROM FERMENTED FOODS IN THAILAND

Fifty-seven strains of rod-shaped lactic acid bacteria were isolated from 16 kinds of fermented foods (meat products, fish products, pickles, and plant products) in Thailand. These isolates were included in the genus Lactobacillus based on phenotypic characteristics. They produced DL-lactic acid homofermentatively, and contained meso-diaminopimelic acid in the peptidoglycan. The isolates were separated into 3 groups by photobiotin labeling DNA-DNA homology. Forty isolates (Group I) showed high degrees of homology (over 71%) with the type strain of Lactobacillus pentosus and were identified as L. pentosus. Tested strains of this group contained straight chain fatty acids of C18:1 and C-16:0 as major components. Sixteen isolates (Group II) showed high degrees of homology (over 72%) with the type strain of Lactobacillus plantarum and were identified as L. plantarum. Tested strains in this group contained straight chain fatty acid of C-16:0 as a major component. The amount of cyclopropane acid of C19 was significant for differentiating L. pentosus and L. plantarum. One isolate (Group III) showed low degree of homology (3%) with the type strains of L. pentosus and L. plantarum, and was not identified as any known species. Detailed characterization and distribution of L. pentosus and L. plantarum in fermented foods in Thailand were discussed.