Production and preliminary characterisation of antibiotics produced by an Actinomycetale strain isolated from Ain Mlila Saltpans(Algeria)

摘要

In search for new antibiotics from actinomycetes,investigating extreme habitats enhances the probability for isolating novel producers.In this context,the antibacterial activity of an actino-mycete strain isolated from saltpans's water(Ain Mlila)was studied.According to morphological and macromorphological characters,this strain could be assigned to one of the genera Streptomyces,Kitasatosporia,Saccharopolyspora or Streptoalloteichus.Antibacterial substances were extracted from mycelium with methanol and from the fermentation medium with three different solvents.The kinetics of growth and antibacterial activity on ISP 2+0.5% NaCl(220 r/ min,28 deg C)showed that the activity of mycelium and that of butanolic extract of the culture medium reached their maximal values in the fourth and fifth days of fermentation,respectively.The chromatographic technique of Betina, revealed that the culture supernatant contained three types of antibacterial molecules,two of them were extracted with butanol,and a third one, which appeared to be a new molecule,was extracted with benzene.The two activities present in the butanolic extract and that extracted from mycelium were related molecules.According to Betina classification, they possessed the basic structure of"related macrolides".These molecules resisted in the supernatant to different pH(3 to 9),were stable at 70 deg C and even after freezing(-20 deg C).