Extraction of antibacterial compounds Selected antagonistic actinobacterial isolates (Streptomyces sp. NIOT-VKKMA02, Streptomyces

sp. NIOT-VKKMA26 and Saccharopolyspora sp. NIOT-VKKMA22) were inoculated into starch casein broth, and incubated on a shaker at 28°C for 7 days. After incubation, find more culture broths were filtered through Whatman No.1 filter paper to separate cell mass from the medium. The cell filtrate was mixed separately in ethyl acetate, ethyl alcohol, methanol and concentrated under pressure in a Buchi Rotavapor R-205 (Buchi Labortechnik AG, Switzerland) at 30°C. Further, the crude solvent extracts were screened for antibacterial activity EPZ004777 ic50 against 12 clinical pathogens by well diffusion assay. A known quantity of 50 μg/well was loaded in Muller Hinton agar plates seeded with test organisms. Negative controls with solvents were also

maintained. After overnight incubation at 37°C, the zone of inhibition was documented in millimeter. To authenticate the antibacterial property of crude extracts, screening assay was carried out in triplicates. Screening of marine actinobacteria for surfactant production Hemolytic activity Screening of isolates GSK1838705A for hemolytic activity were performed in blood agar medium containing 5% (w/v) peptone, 3% (w/v) yeast extract, 5% (w/v) NaCl and 5% (v/v) human blood [24]. Plates were examined for hemolysis after incubation at 37°C for 5 days. Presence of clear zone around colonies signifies the potential of isolates for surfactant production. Screening for lipase production Aptitude of the isolates to synthesize extracellular lipase was monitored using ISP 2 medium with 1% (w/v) tributyrin with MycoClean Mycoplasma Removal Kit pH 7.4. A loopful of inoculum was streaked on to test agar plates and incubated at 30°C for 7 days. After

incubation, the plates were examined for potential lipase producers by recording clear zone around colonies. Production medium Potential isolates (Streptomyces sp. NIOT-VKKMA02, Streptomyces sp. NIOT-VKKMA26 and Saccharopolyspora sp. NIOT-VKKMA22) for surfactant biosynthesis was further cultivated in production medium with 5% (w/v) peptone, 1% (w/v) yeast extract, 10% (w/v) glucose, 1% (w/v) NaCl, 0.5% (w/v) K2HPO4, 0.1% (w/v) FeSO4, 0.2% (w/v) Na2CO3 and 0.1% (w/v) MgSO4, with pH 7 and incubated at 28°C for 7 days on a shaker incubator at 200 rpm. Drop collapsing test Quantitative drop-collapse test to confirm surfactant production by potential isolates was performed as described by Youssef et al. [25]. Briefly, 0.02% (v/v) mineral oil was stacked on to 96 well microtitre plates and equilibrated for 1 h at 37°C. Subsequently, 5 μl of culture supernatant was added to the surface of oil and the shape of supernatant on oil surface was observed after 1 min.