2.3. Pretreatment of samples
The samples were subjected to various physical and chemical pretreatment methods in order to facilitate isolation of actinomycetes[25]. The sediment samples were air dried; heated aseptically, which stimulates the isolation of actinomycetes by eliminating most unwanted Gram negative bacteria. Appropriate selective media such as starch casein agar, glycerol yeast extract agar and antifungal antibiotics (amphotericin B) at 25 µg/mL were used for actinomycetes growth promotion and also for prevention of fungal contamination[26],[27]