Isolation and Characterization of Antibiotic-producing Actinomycetes from hot spring sediment of Thailand

In the course of our investigation for the antibiotic-producing actinomycetes. Thirty-two actinomycete strains were isolated from Thai hot spring sediment. The generic identities of these isolates were determined by using a procedure that combined morphological, chemotaxonomic and 16S rDNA sequence-based phylogenetic analyses. Actinomycetes belonging to a total of 4 genera were identified. They were members of Streptomyces, Micromonospora, Microbispora and Planosporangium. The fermentation broths of these isolates were extracted with ethyl acetate and were tested for antimicrobial activity. The results showed that more than 50 % of the actinomycete strains inhibited at least one of the tested micro-organisms. Based on these results, we conclude that actinomycete diversity in the hot spring sediment is great and should represent an excellent source for discovery of the bioactive compounds.