The Role of Quorum Sensing in Enhancing Lovastatin and Pigment Production in Monascus purpureus C322

Monascus purpureus is a filamentous fungus known for producing pharmaceutically valuable secondary metabolites, including azaphilone pigments and lovastatin. Lovastatin is an HMG-CoA reductase inhibitor widely used to manage hypercholesterolaemia, while Monascus pigments serve as natural colourants with antioxidant and antimicrobial properties. This study evaluated the impact of quorum-sensing molecules (QSMs)—tyrosol (0.3 mM), farnesol (0.2 mM) and linoleic acid (0.4 mM)—on pigment and lovastatin yields in shake flasks and 2.5 L stirred-tank bioreactors. QSMs were introduced 48 h post-inoculation in shake flasks and 24 h in bioreactors. All QSMs increased yellow (OD400), orange (OD470), and red (OD510) pigments and lovastatin concentration relative to the control, with scale-up further enhancing yields. Farnesol produced the most pronounced effect: in flasks, OD400 7.10 (1.86-fold), OD470 8.00 (2.12-fold), OD510 7.80 (2.08-fold), and 74.6 mg/L lovastatin (2.05-fold); in bioreactors, OD400 11.9 (2.06-fold), OD470 15.1 (2.71-fold), OD510 13.7 (2.47-fold), and 97.2 mg/L lovastatin (2.48-fold). This was followed by tyrosol treatment and then linoleic acid. These findings demonstrate that QSMs—particularly farnesol—significantly (p < 0.01) stimulate pigment and lovastatin biosynthesis in M. purpureus. Quorum sensing modulation represents a promising, scalable strategy to optimise fungal fermentation for industrial metabolite production.