Enhanced production of Monacolin K by addition of precursors and surfactants in submerged fermentation of Monascus purpureus 9901.

The main problem in Monacolin K (MK) production by submerged fermentation of Monascus purpureus is low productivity. In this study, on one hand, addition of precursors was used to activate the biosynthesis of MK. When 4.0 g/L of sodium citrate was supplemented at the 48th H of the fermentation, the final MK production reached to 1,658.9 ± 28.5 mg/L after 20 day of fermentation, which was improved by 52.6% compared with that of the control. On the other hand, addition of surfactants could increase the permeability of cell membrane, thus driving more intracellular metabolites secreted into the fermentation broth and alleviating the product inhibition. When 40.0 g/L of Triton X-100 was added at the beginning of the fermentation, the final MK production reached to 2,026.0 ± 30.4 mg/L after 20 day of fermentation, which was improved by 84.9% compared with that of the control. These results are helpful to provide some new insights into the biosynthetic regulation on MK production; the approach can be applied to other fungal fermentation processes for enhancing production of useful metabolites.