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Optimization of divalent metal cations for maximal concentration of Monacolin K in Monascus M1 by response surface methodology

Inorganic salts are important factors in the growth and secondary metabolites production of microorganisms. This study investigated the influences of divalent metal cations, Mn2+, Zn2+, and Mg2+ on the cell growth and Monacolin K production in Monascus M1. Then the concentration of the three kinds of divalent metal cations was optimized by response surface methodology, and the optimum conditions for the highest production of Monacolin K were determined. The optimum concentrations of the three divalent metal ions were selected as follow: Mn2+ 0.33%, Zn2+ 0.16%, and Mg2+ 1%. In this condition the concentration of Monacolin K reached 9.57mg/g which was close to the predicted values, indicating that the model was adequate for the Monacolin K production. The yield of Monacolin K in Monascus can be increased by adding metal ions during industrial production.