Abstract:

The aim of this study is to improve the chromatic value of Monascus pigment, providing technical support for its widespread applications. To achieve the aim, the liquid medium for Monascus pigments production by Monascus purpureus fermentation was optimized using single-factor experiments and response surface methodology (RSM). Plackett-Burman design and steepest ascent experiments were employed to identify three key factors significantly affecting chromatic value of Monascus pigment including glucose, peptone, and KH₂PO_4, and the maximum response intervals of these factors were determined. Subsequently, a Box-Behnken design was used to optimize the medium composition, resulting in the following optimal medium formulation: glucose 59.3 g/L, peptone 30.5 g/L, KH₂PO₄ 0.8 g/L, MgSO₄ 1.0 g/L, ZnSO₄ 0.1 g/L. Under such optimized medium, the chromatic value of Monascus pigment reached 268.49 U/mL, which was 3.23 times higher than that achieved before optimization. The results demonstrate that response surface methodology is a highly efficient tool for optimizing culture media and this optimization significantly improves the yield of Monascus pigment.

Key words: Monascus purpureus, the chromatic value of Monascus pigment, single factor experiment, response surface experiment, medium optimization, Plackett-Burman test, steepest climb test, Box-Behnken test