Optimization of the Monascus purpureus Fermentation Process Based on Multiple Performance Characteristics

The fermentation process in general is a kind of non-linear and time-variant system. It is necessary to determine optimal conditions in the fermentation process with multiple performance characteristics In this study, a Grey-based Taguchi Method was applied to find the optimal conditions of medium composition to enhance the production of biomass, monacolin K, pigments synthesis, and to reduce the yield of citrinin, metabolites in the Monascus purpureus fermentation process. In particular, the amount of citrinin would cause potential adverse effects on human health and depends on the quality and control of the fermentation process. The results show that the optimal conditions under these multiple performance requirements for Monascus purpureus fermentation are: A4 (1% whole wheat flour), B3 (1% pepton), C1 (1% olive oil), D4 (0.01% KH2PO4), E1 (pH=3). That combination can yield iomass at 2.065 g/100mL, monacolin K at 150.052 ppm, yellow pigment (OD400) at 4.082 ppm, orange pigment (OD460) at 4.231 ppm, red pigment (OD400) at 8.105 ppm, respectively, with ctirinin yield reduced to 0.082 ppb. The optimal combination obtained from this study could be a reference for production line fermentation processing.