methods 2.1. Microorganism and culture conditions
A strain of Aureobasidium pullulans MTCC 2670 was purchased from Microbial Type Culture Collection (MTCC), Chandigarh, India. Stock culture was sustained on potato dextrose agar (PDA) medium at 4◦C and was revived once in every three weeks.The growth medium comprising the following composition was prepared and sterilized (in g/l): glucose – 50, yeast extract – 2.5,K2HPO4– 5, (NH4)2SO4– 0.6, MgSO4·7H2O – 0.2 and NaCl – 1.Before sterilization, the pH of the medium was adjusted to 6.8 using 1 N NaOH or 1 N HCl. After cooling, two loops of micro organism were inoculated to 150 ml sterile growth medium. The fermenta-tion medium was then incubated at 30◦C in an orbital shaker for 48 h at 200 rpm.