Efficient Biosynthesis of Natural Yellow Pigments by Monascus purpureus in a Novel Integrated Fermentation System

Because of the increasing demand for healthy and safe food, Monascus spp. have gained much attention as a sustainable source of natural food colorant. In this study, a novel integrated fermentation system consisting of surfactant and in situ extractant was established for efficiently producing yellow pigments by M. purpureus sjs-6. The maximum production of Monascus yellow pigment (669.2 U/mL) was obtained when 40% soybean oil (as extractant) was supplied at the beginning and 5 g/L Span-80 (as surfactant) was supplied at the 72nd h, which resulted in production 27.8-times of that of the control. Critical factors such as alleviating the product inhibition, increasing the membrane permeability, changing the hyphal morphology, and influencing the cell activity have been suggested as the underlying mechanisms. This system is of great significance for the bioprocess, which suffers product inhibition, and it can serve as a promising step for enhancing the yield of hydrophobic metabolites.