Isolation and characterization of actinomycetes from Brazilian tropical soils

Actinomycetes have been isolated from three Brazilian tropical soils. The dispersion and differential centrifugation procedure revealed count values 1.5 to 5.0 times greater than those obtained by the conventional dilution plate technique for all soils and media tested. Eighteen strains, promising for biotechnological applications, were submitted to chemotaxonomic procedures and numerical taxonomy for identification. Two were identified as Amycolatopsis orientalis, one as Streptomyces misakiensis, and two tentatively included or associated to S. chromofuscus and S. griseoruber. The others, all belonging to the Streptomyces genus, could not be fitted into any known species, and were arranged by the UPGMA analysis for classification, as an isolated group. This suggests that the actinomycetes in tropical soils may represent a vast unexplored resource for biotechnology.