Integrated fermentation optimization and downstream purification strategies for enhanced monascin and ankaflavin production by Monascus purpureus TST

Monascin (MS) and ankaflavin (AK) are bioactive yellow pigments produced by Monascus species, known for their health benefits and safety profile compared to monacolin K. This study developed an integrated strategy combining Response Surface Methodology (RSM) for submerged fermentation optimization and a downstream purification process to maximize MS and AK production by Monascus purpureus TST. Although the results of this study demonstrate that RSM did not successfully predict the optimal production conditions, the RSM optimization revealed significant interactions between sucrose, ammonium sulfate, and magnesium sulfate heptahydrate. Verification experiments confirmed that the optimal culture conditions for M. purpureus TST were 200 g/L sucrose, 17.5 g/L (NH 4 ) 2 SO 4 , and 0.1 g/L MgSO 4 · 7H 2 O. Under these conditions, MS and AK yields reached 2987 ± 530 mg/L and 1678 ± 259 mg/L, representing 5.98-fold and 3.72-fold increases, respectively, while restricting CT production to 0.96 mg/L. Furthermore, a streamlined purification protocol involving an aminophilic reaction for orange pigment removal, followed by n -hexane extraction and column chromatography, was established. This method achieved purification factors of 7564 and 10,679 for MS and AK, respectively, with high purity (> 90%, determined by an HPLC calibration curve on a weight basis). These findings represent highly competitive MS and AK productivities in Monascus submerged fermentation using non-genetic engineering approaches. providing a potential basis for industrial-scale production. Although this study explored the optimization of MS and AK production through Monascus submerged fermentation, many critical influencing factors are difficult to adequately investigate in shake-flask cultures. Building upon the findings of this study, future research should employ bioreactors for more in-depth investigations into fermentation production.