Twelve actinomycete strains were isolated from lichens collected in Thailand. On the basis of their phenotypic and chemotaxonomic characteristics including 16S rRNA gene sequences analysis, they were divided into 2 genera, Streptomyces (Group 1, 9 isolates) and Actinoplanes (Group 2, 3 isolates). Isolates LDG1-03 and LDG1-15; LDG1-05 and LDG2-02; LDG1-08; LDG1-16; LDG2-09; LLG1-01; and LLG1-03 were closely related to S. malaysiensis NBRC 16446T (98.95-99.85%); S. lomondensis NBRCT (99.77-99.78%); S. graminearus NBRC 15420T (98.72 %); S. parvulus NBRC 13193T (100%); S. cinereoruber subsp. cinereoruber NBRC 12756T(99.11%); S. seoulensis NBRC 16668T (100%); and S. cinerochromogenes NBRC 13822 T (99.17%) based on 16S rRNA gene sequences analysis, respectively. The isolates LDG1-06, LDG1-22A and LDG1-22B are closely related to A. deccanensis IFO 13994T and A. nipponensis FH 2241 T (97.97-98.93 %), respectively. The isolates in Group 1 contained LL-diaminopimelic acid in cell wall and had MK-9(H6), MK-9(H8) and MK-9(H4) as the major menaquinones. The isolates in Group 2 contained meso-diaminopimelic acid and had MK-9(H6) and MK-9(H4) as the major menaquinones. Four Streptomyces isolates exhibited antimicrobial activity against Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Kocuria rhizophila ATCC 9341 and Candida albicans ATCC 27853 while Actinoplanes isolate LDG1-06 exhibited against C. albicans ATCC 27853.
Key words: Actinomycetes, Streptomyces, Actinoplanes, antimicrobial activity, lichens
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