Prodigiosin is a tripyrrole-based microbial pigment that exhibits diverse biological activities, including antioxidant, antimicrobial, and anticancer properties. Moreover, it possesses excellent color fastness and dye uptake, making it a promising candidate in medicine, cosmetics and dye industries. In this study, the high-prodigiosin-producing mutant Serratia marcescens strain GEN-M54 was obtained through sequential physical and chemical mutagenesis. The effect of light on the prodigiosin production was investigated, and a two-step sequential light fermentation strategy was developed to promote the prodigiosin accumulation. Additionally, gene transcription analysis was conducted to elucidate changes in the metabolic flux of prodigiosin precursor synthesis under red-light stress conditions. Finally, a prodigiosin production of 6623.1 mg/L and a content of 471.4 mg/g were achieved through the two-step fermentation strategy, representing an increase of 77.1% and 46.8%, respectively. Overall, this study provides an efficient microbial platform and an efficient fermentation strategy for future prodigiosin production.

Violacein is a natural purple secondary metabolite with a wide range of biological activities including antibacterial, anticancer, antioxidant, and antiparasitic properties, rendering it a highly promising candidate for applications in medicine, agriculture, and food industries. Despite its availability from natural sources, a profound understanding of its production mechanisms has long been lacking. High-level production of violacein has been achieved through integrated strategies, including heterologous expression of its biosynthetic pathway in recombinant strains, enhancement of tryptophan precursor supply, and optimization of fermentation conditions. These approaches offer a flexible and scalable platform for violacein biosynthesis. Furthermore, recent efforts have focused on utilizing agro-industrial waste as a cost-effective and sustainable feedstock to further improve production efficiency and environmental compatibility. This review provides a comprehensive overview of the latest advancements in violacein production, examines the challenges associated with its application, and proposes strategies for optimizing gene expression, refining fermentation protocols, and utilizing low-cost raw materials to facilitate the efficient and sustainable violacein production.