The Optimization of Monascus Fermentation Process for Pigments Increment and Citrinin Reduction

The species of the fungus (Monascus purpureus, NPUST, Taiwan) used to produce the high pigment was isolated from rice waste. Its genomic DNA was confirmed by examining the NCBI database to check this species is M. purpureus strain ATCC 36114 (Identity 100%, Gap 0%). In this study, Taguchi Method was applied to find the optimal conditions of medium composition to enhance the production of pigments synthesis, and to reduce the yield of citrinin, metabolites in the M. purpureus fermentation process. In the production of the yellow pigment (OD₄₀₀) and the red pigment (OD₅₀₀), the result showed that their optimal conditions were A₂B₃C₃D₄E₄ (1% Japonica-type rice, 1% peptone, 0.01% glycerol, 0.01% potassium phosphate and pH 9). In the production of the orange pigment (OD₄₆₀), the result showed that the optimal conditions were A₂B₃C₃D₁E₄ (1% Japonica-type rice, 1% peptone, 0.01% glycerol, 0.01% magnesium sulfate and pH 9). Under the optimal conditions for the best yield of pigment synthesis, the result showed that yellow pigment was 4.132 ppm, red pigment was 8.480 ppm and the orange pigment was 4.573 ppm. In the reduction of the citrinin yield, the result showed that A₄B₁C₁D₃E₁ (1% whole wheat flour, 1% gelatin, 0.01% olive oil, 0.01% sodium choride and pH 3) were optimal conditions inhibit citrinin metabolism. Citrinin was reduced to 0.055 ppb. The optimal combination obtained from this study could be a reference for production line Monascus fermentation processing.