Scaffold-based Monascus cultivation: a controllable alternative to conventional red yeast rice for Hong Qu rice wine fermentation

Traditional Hong Qu rice wine fermentation relies on solid-state cultivation of red yeast rice, where Monascus grows primarily on the two-dimensional (2D) surface of rice, resulting in limited cultivation controllability. In this study, we developed a three-dimensional (3D) printing bio-ink system supporting Monascus mycelia growth, exhibiting pronounced shear thinning and rapid structural recovery after deformation. The resulting 3D-printed scaffolds featured an interconnected porous microstructure and suitable textural properties, achieving total pigment production by Monascus of up to approximately 215 U / g . Comparative transcriptomic analysis between 3D scaffold cultures and conventional 2D planar cultures revealed that 3D cultivation remarkably upregulated pathways associated with lipid metabolism, energy metabolism, and oxidation-reduction processes, indicating that the 3D cultivation mode enhances secondary metabolic activity. Subsequent wine fermentation using the 3D-cultivated scaffolds produced scaffold-based wine (SW) with physicochemical properties, secondary metabolite profiles, and flavor characteristics comparable to those of traditional Hong Qu rice wine (HQW), while exhibiting a distinctive flavor profile characterized by higher phenethyl alcohol content (247.24 μg/mL) and a more balanced organic acid composition. SW also showed enhanced antioxidant capacity, with ABTS radical scavenging activity approximately 1.3-fold higher than that of HQW. Meanwhile, SW achieved an approximately 28% higher total pigment content than wines obtained from 2D cultivation approaches. Overall, this work proposes a 3D scaffold-based Monascus cultivation and fermentation strategy for HQW production, enabling improved controllability of the fermentation environment while maintaining the characteristic quality of traditional products, and providing a practical alternative to conventional red yeast rice-based fermentation systems.