Abstract
Starmerella bombicola a teleomorph of Candida bombicola is capable of producing extracellular secondary metabolites known as sophorolipids. In the present work the performance of Starmerella in producing sophorolipids, with standard medium ingredients glucose, sunflower oil, yeast extract and urea was studied. The quantities of different medium ingredients were optimized to maximize the production of sophorolipids. Variation in tensiometric properties like surface tension and interfacial tension during the incubation period were also reported. The optimized mixed substrate composition was found to be 200 g/l, containing equal amounts of glucose and sunflower oil, 4 g/l of yeast extract and 0.6 g/l of urea. With the optimized substrate composition 38.6 g/l of sophorolipids was obtained. The minimum surface tension produced by the culture free cell broth was 36.2 mN/m. Increasing the temperature from 25°C to 35°C has shown adverse effects on sophorolipids production.