factorial study of the interaction of nitrogen and carbon sources, pH and temperature with time regarding antibiotic production by streptomyces parvulus using three test bacteria

ABSTRACT

Interaction of nitrogen and carbon sources, pH and temperature [NaNO3, starch, pH and temperature, respectively] with incubation time regarding antibiotic production by Streptomyces parvulus isolated from Burg El-Arab, East Alexandria City, Egypt was performed. Antibiotic production was evaluated against Staphylococcus aureus, Sarcina lutea and Escherichia coli strains. Experiments were carried out using a factorial interaction design consisting of sixteen trials at five different incubation times. Responses of the three test bacteria to the antibiotic components produced by Streptomyces parvulus were found to differ with differences in the level of each of the four studied factors [variables] in addition to differences in the incubation period of time. Anti-Staphylococcus aureus of the culture filtrates of the producer was found to be highly sensitive to variations in trials constructions in case of incubation for only 3 days followed by 6 then 9 days less in 12 days period and finally it showed no significant responses after 15 days incubation. Anti-Sarcina lutea responses to differences in different trials were recorded to show two maxima at 9 and 15 days of incubation. Anti-E. coli responses were considerable after 3 days of incubation followed by 15 days. The most effective combination suitable for production of the antibiotic component whatever the incubation period and the test bacteria was the factor of temperature [T] at its raised level which is [30C]. Other combinations exhibited variable effects depending on time and test organism