Biosynthesis and Applications of Monascus Pigments

Monascus pigments, a family of polyketide-derived compounds synthesised by Monascus spp., encompass yellow (ankaflavin, monascin), orange (rubropunctatin, monascorubrin) and red (monascorubramine, rubropunctamine) chromophores. Biosynthesis is orchestrated by a dedicated gene cluster encoding a non-reducing polyketide synthase, tailoring enzymes and regulatory factors. Primary metabolic flux through acetyl-CoA and malonyl-CoA pools, together with stress signals such as carbon limitation or pH shifts, directs pigment production and modulates co-metabolite formation. Citrinin, a nephrotoxic by-product, arises from an adjacent polyketide pathway and poses safety constraints. Advances in genomic and transcriptomic analyses have elucidated evolutionarily conserved regulatory nodes and uncovered mechanisms by which central carbon metabolism, NADPH availability and transcriptional networks converge to balance pigment yield and toxigenic risk. Applications of Monascus pigments span natural food colourants, functional additives with antioxidant and cholesterol-lowering properties, pharmaceutical precursors such as monacolin K, and dyeing agents in textiles. Innovative fermentation strategies—ranging from solid-state to high-cell-density submerged systems—combined with tailored substrates and bioprocess control, have improved pigment titres and stability. Engineering of low-citrinin strains and exploration of agro-industrial wastes as feedstocks underpin sustainable production and broaden market prospects. Ongoing efforts integrate systems biology, strain engineering and green process design to meet regulatory standards and consumer demand for safe, multifunctional natural colourants.

Research from Nature Portfolio

A complete genome sequence and comparative transcriptomic analysis of an industrial Monascus purpureus strain revealed a 24.1 Mb genome with a reduced gene repertoire adapted to starch-rich substrates. Annotation of the pigment biosynthetic gene cluster provided the first comprehensive map of enzymatic steps from polyketide backbone assembly to chromophore diversification. Transcriptome profiling under carbon-starvation stress demonstrated repression of central glycolysis and up-regulation of acetyl-CoA-generating pathways, thereby enhancing precursor supply for pigment synthesis. Key transcription factors and potential isoenzymes were identified that differentially regulate pigment versus citrinin clusters. These genomic insights now form the basis for targeted metabolic engineering to elevate pigment production while minimising mycotoxin formation.

Biosynthesis and Applications of Monascus Pigments publication trend

The graph below shows the total number of articles in biosynthesis and applications of monascus pigments across all publications each year (not limited to Nature Index journals).

Technical terms

Polyketide synthase (PKS): A multi-domain enzyme that assembles polyketide backbones from simple acyl-CoA precursors.

Acetyl-CoA pool: The intracellular reservoir of acetyl coenzyme A serving as a key precursor for polyketide biosynthesis.

Solid-state fermentation: Cultivation on moist solid substrates without free aqueous phase, often yielding high titres of fungal metabolites.

Dissolved oxygen (DO): The concentration of oxygen available in a submerged culture, influencing metabolic flux and secondary metabolite synthesis.

Citrinin: A mycotoxin produced by Monascus species via a separate polyketide pathway, with nephrotoxic and hepatotoxic effects.

References

1. Recent advances in monascus pigments produced by Monascus purpureus: Biosynthesis, fermentation, function, and application. LWT (2023).
2. Complete genome sequence and transcriptomics analyses reveal pigment biosynthesis and regulatory mechanisms in an industrial strain, Monascus purpureus YY-1. Scientific Reports (2015).
3. Production of the secondary metabolites γ-aminobutyric acid and monacolin K by Monascus. Journal of Industrial Microbiology & Biotechnology (2003).
4. Natural Red Pigment Production by Monascus Purpureus in Submerged Fermentation Systems Using a Food Industry Waste: Brewer’s Spent Grain. Foods (2019).
5. The pigment characteristics and productivity shifting in high cell density culture of Monascus anka mycelia. BMC Biotechnology (2015).
6. Effect of initial pH, different nitrogen sources, and cultivation time on the production of yellow or orange Monascus purpureus pigments and the mycotoxin citrinin. Food Science & Nutrition (2019).