| dc.description.abstract | The genus Streptomyces produced more than 70 % of known antibiotics widely used in medicine, veterinary and agriculture, thus it has been considered as one of the most important industrial microorganisms worldwide. Streptomyces spp. LTB08 was isolated from infested soil in Ho Chi Minh City. In our previous study, this bacterium has shown remarkably strong antimicrobial activity against S. aureus ATCC 29213. Therefore, with this study, we aimed to characterize properties of the antimicrobial compounds produced by the organism. To do this, the antimicrobial activity of the supernatant was evaluated upon heat treatment, protease treatment and SDS-PAGE analysis. Furthermore, TLC and column chromatography were applied to analyze which fraction of acetone crude extract from LTB08 would have antimicrobial activity. Results showed that antimicrobial compounds from LTB08 was heat-sensitive with no antimicrobial activity obtained after 100oC treatment for 30 minutes and 60 minutes; up to 31% reduction in activity after 75oC treatment for 60 minutes. No reduction in antimicrobial activity was observed after protease treatment (trypsin and chymotrypsin) even though proteins were still found in the extract indicated via SDS-PAGE result. This result indicated that the main antimicrobial compounds of LTB08 were not of protein nature. The separation of acetone crude extract with silica gel 60 column in methanol-acetone solvent provided total four fractions, among which only the fraction II (Rf = 0.75) showed inhibition activity against S. aureus ATCC 29213.
Keywords: Streptomyces spp. LTB08, antimicrobial activity, heat-treated, protease-treated, column chromatography, SDS-PAGE. | en_US |
