The microorganism used in this study was M. purpureus
NRRL1992. Stock cultures were maintained on Sabouraud
dextrose agar plates and subcultured periodically. Cultures
reactivated by transferring onto fresh Sabouraud plates
and cultured at 30 1C for 8–12 days were used for inoculum
preparation. The submerged culture media contained the
carbon and nitrogen sources (as specified below) and in g/l:
K2HPO4 (5.0), KH2PO4 (5.0), MgSO4 7H2O (0.01), CaCl2
(0.01) and ZnSO4 7H2O (0.01). The initial pH of the
medium was adjusted to 6.0. Erlenmeyer flasks (125ml)
containing 25ml of medium were inoculated with 250 mlof
a mycelium/spores suspension (in a 0.85% NaCl sterile
solution) with an O.D.620 of approximately 0.4. The flasks
were incubated at 2573 1C for 9 days in a rotatory shaker
at 100 rpm. The concentration of extracellular red pigment
was estimated by measuring the absorbance of filtrates at
500 nm, taking the dilution factor into consideration.