OPTIMAL CONDITIONS, EXTRACTION, AND PARTIAL PURIFICATION OF A POTENTIAL NOVEL ANTIMICROBIAL COMPOUND PRODUCED BY STREPTOMYCES N-404 STRAINISMAIL SAADOUN, FOUAD AL-MOMANI AND MAHER OBEIDAT
In this study the optimal conditions in addition to extraction, partial purification and characterization of antimicrobial compound produced by Streptomyces N-404 strain were determined. Results showed that Streptomyces N-404 strain optimally produced the antimicrobial compound against the test organisms after 5 days of incubation in nutrient broth at 28 ÂºC and initial pH of 8.5. Analysis of the cell free broth revealed that it contains an antimicrobial compound which was stable over a wide range of pHs and temperatures, and retained inhibitory activity after heating and treatment with different enzymes. The minimum inhibitory concentration (MIC) of the water soluble of concentrated ethanolic crude extract against Staphylococcus aureus and Escherichia coli was 5 and 10 mg/mL, respectively. Purification experiments for the active compound out of permutite column by a gradient solution of KOH revealed the elution of one major peak and a 74% increase in activity against S. aureus with a maximum inhibition zone diameter of 33 mm. When Streptomyces N-404 strain was tested for its sensitivity to gentamycin and kanamycin and the partial purified active compound was compared to these antibiotics, data indicated that this strain is not producing these 2 antibiotics, and the active compound resemble them in their temperature and pH stability, but differs from these compounds in TLC pattern, adsorption to charcoal under basic and acidic conditions, and UV spectrum. These findings stress the novelty of the inhibitory compound produced by Streptomyces N-404 strain.