Candida tropicalis BPU1, a novel isolate from the rumen of the Malabari goat, is a dual producer of biosurfactant and polyhydroxybutyrate.

This unique study reports a new strain (BPU1) of Candida tropicalis isolated from the rumen of the Malabari goat, showing dual production of biosurfactant and polyhydroxybutyrate. C. tropicalis strain BPU1, a facultative anaerobe, was tuned to become an aerobe in specially designed flask, the Benjamin flask. The puffy circular colonies were smooth, white-to-cream in colour, with pseudo-filaments. The strain fermented glucose, sucrose, maltose and dextrose, but not lactose and cellulose. It assimilated (NH4 )2 SO4 , peptone, glycine and arginine, but not NaNO3 , as the nitrogen source. Interestingly, it utilized groundnut oil (up to 0.3%) in a specially designed basal mineral salt medium (BSM). Its capability for dual production of a biosurfactant and a polyhydroxybutyarate (PHB) was explored by various methods from the BSM-oil medium. Extracted biosurfactant from 6 day-old culture was biochemically characterized as a complex of lipid and carbohydrate with an Rf value of 0.88 by thin layer chromatography. Its PHB production was confirmed by specific staining methods with Nile blue sulphate, Sudan black B and Sudan 3. Briefly, this first-ever report gives ample physical evidence for the dual production of a glycolipid (biosurfactant) and PHB by C. tropicalis strain BPU1 on a specially designed medium, which would open up elaborate research on this yeast.