Selección de cepas de Bacillus spp. productoras de antiobióticos aisladas de frutos tropicales

the aim of this work was to isolate and select bacillus strains according to their ability to produce antibiotic substances useful in the control of postharvest diseases of tropical fruits. fifty strains were isolated from the surface of tropical fruits and from soil samples. eight strains showed better in vitro inhibition rates versus postharvest fungi of tropical fruits. lipopeptidic antibiotics were extracted with 1-butanol and analyzed by high-pressure liquid chromatography (hplc) with a c18 column varian？. the mobile phase was acetonitrile (0-80 % v/v). the isolated strains produced antibiotics from the family iturin a and surfactin. the strain pla10 produced the highest concentrations of iturin a and surfactin. iturin a fractions had fungicidal activity, but the surfactin fractions did not show any activity. however, when both fractions were applied together, a synergistic effect was obtained during the inhibition of colletotrichum sp. from mango. the strain pla10 was identified as bacillus subtilis.