*3.3. Isolation of Microorganisms*

The secreted mucous net of polychaete were pre-rinsed in sterilized sea water. Pieces of tissue (about 1 g) were aseptically removed and homogenized in 5 mL sterilized sea water. Bacterial strains were isolated by plating samples of tissue homogenate (0.1 mL) onto Petri dishes with the modified MN medium containing 75% natural sea water, 25% distilled water, 0.12 mM CaCl2, 0.15 mM MgSO4 × 7H2O, 0.09 mM K2HPO4 × 3H2O, 8.8 mM NaNO3, 0.19 mM Na2CO3, 0.0013 mM disodium EDTA, 0.014 mM Citric acid × H2O, 0.015 mM Ferric ammonium citrate, 1% Bacto agar at pH 8.5. These dishes were incubated aerobically at 20 ◦C for 10 days. The bacterial colonies that grew on the modified MN medium were picked up and then pure bacterial cultures were grown on DifcoTMMarine Agar 2216

(BD) and classified morphologically and biochemically. Bacterial strains were stored in 30% glycerol solution at −80 ◦C.
