Collective Effects of Stress on Optimization of Pigment Production by Monascus purpureus

Monascus sp. is well-known for pigment production and its application as food colorants. The aim of this study was to optimize the pigment yield and biomass produced from Monascus purpureus in submerged culture under the combined effect of various stress conditions. In this experiment, the thermal stress was induced by incubating the spores at various temperature ranges. For inducing osmotic stress, varied concentrations of NaCl, glycerol and peptone were used. Pigment and biomass was statistically optimized with response surface methodology (RSM). A 2(4) full factorial central composite design (CCD) was applied to elucidate the combined effects of above mentioned stress conditions. The results showed that the linear effect of glycerol on pigment yield was more significant. The optimum calculated values for the test variables in coded factors was estimated at 71.25 colour value units (CVU)/ml as against the experimented value of 68.67 CVU/ml at 70 degrees C for temperature, 1.087 mol/l (w/v) for glycerol, 1.25% (w/v) for peptone and 0.25% (w/v) for NaCl. Statistically optimized pigment yield was amazingly found to be almost two fold as compared to the control.