Effect of arginine supplementation on Monacolin K yield of Monascus purpureus

Through a screening process, we previously revealed that the addition of arginine to Monascus fermentation broth significantly increased Monacolin K production, with 0.6 % arginine showing the best effects. Herein, we added 0.6 % arginine to further detect the effect of arginine on secondary metabolites and mycelium morphology of Monascus purpureus. When M. purpureus was grown in a medium supplemented with arginine, the Monacolin K yield increased from 94.6 to 228.4 mg/L, indicating an increase of approximately 2.4-fold. Further, there were significant increases in Monascus pigments. Scanning electron microscopy of Monascus mycelium morphology showed that arginine significantly altered the mycelial morphology and enhanced the extracellular secretion of Monacolin K. RT-qPCR showed that after the addition of arginine, expression of all the mokA-mokI genes were upregulated. These results indicate that arginine could increase the yield of Monacolin K, providing a basis for further analysis of Monacolin K biosynthesis.