Studies on bioemulsifier production by Actinopolyspora sp. A18 isolated from garden soil

Out of the 13 species of actinomycetes isolated from garden soil, 10 tested positive for lipase and emulsification activity. Actinopolyspora sp. A18 exhibiting maximum activity was further studied and partially purified. Actinopolyspora sp. A18 exhibited maximum bioemulsifier production during stationary phase at 72 h. Maximum bioemulsifier production was obtained at 30 degree C, pH 8, 250 rpm and 2% (w/v) NaCl concentration. Emulsification activity was maximum (316 EU mL super(-1)) with sunflower oil as substrate. The yield of purified bioemulsifier was 1 g/L and reduced the surface tension of water slightly (7 mN/m). Partially purified bioemulsifier from Actinopolyspora sp. A18 was a glycolipopeptide comprising of 68% protein, 22.20% non-reducing sugars, 4.80% reducing sugars and 5% lipids. The bioemulsifier produced was stable at room temperature for 7 d.