From rare pigment to industrial bioproduct: How engineered microbes are boosting violacein production

This review demonstrates that high-level violacein production is now achievable by combining optimized biosynthetic pathways, enhanced precursor supply, and finely tuned fermentation strategies, while also highlighting routes to reduce costs and environmental impact through low-value feedstocks.

Violacein is a naturally occurring purple secondary metabolite known for its broad biological activities, including antibacterial, anticancer, antioxidant, antiparasitic, and antiviral effects, as well as strong dyeing properties. Despite this versatility, commercial exploitation has long been constrained by low yields from natural producers and inefficiencies in chemical synthesis. Traditional extraction from native bacteria suffers from limited productivity, safety concerns, and poor genetic tractability, while chemical routes are prone to side reactions and costly purification steps. Against this backdrop, microbial fermentation has emerged as a promising solution, benefiting from advances in metabolic engineering, strain optimization, and process control. Over the past decade, researchers have increasingly focused on reconstructing violacein biosynthesis in well-characterized microbial hosts, improving precursor availability—especially L-tryptophan—and designing fermentation systems that balance growth, productivity, and product toxicity, thereby laying the foundation for scalable and sustainable production. 

A study (DOI: 10.1016/j.bidere.2025.100043) published in BioDesign Research on 21 August 2025 by Feng Guo’s & Fengxue Xin’s team, Nanjing Tech University, positions violacein as a realistic candidate for industrial deployment in medicine, agriculture, food systems, and bio-based materials, offering a sustainable alternative to chemical synthesis.

In detail, this review first outlines the violacein biosynthetic pathway encoded by the vioABCDE gene cluster, which converts L-tryptophan into violacein through a sequence of oxidative and coupling reactions. Because this pathway competes for cellular reducing power and is prone to byproduct formation, precise regulation is essential. The researchers overview how quorum sensing, transcriptional control, and translational tuning jointly regulate violacein synthesis in native producers such as Chromobacterium violaceum and Janthinobacterium species. While these organisms provide valuable biological insight, their pathogenicity or limited genetic tools restrict industrial use. Consequently, safer and more tractable hosts—including Escherichia coli, Corynebacterium glutamicum, and Yarrowia lipolytica—have been engineered to express the violacein pathway. In these systems, boosting L-tryptophan supply, relieving feedback inhibition, and optimizing promoter and ribosome-binding-site strength have proven critical. Fed-batch strategies, two-stage temperature control, and biosensor-guided regulation further enhance productivity. Beyond genetic approaches, the review highlights non-metabolic strategies—such as controlled abiotic stress, surfactant addition, and trace metal optimization—that stimulate secondary metabolism and improve product release. Importantly, the use of agro-industrial residues, including soybean meal and sugarcane bagasse, demonstrates that violacein production can be coupled with waste valorization, improving both economics and sustainability.

In summary, this review concludes that violacein has moved from an intriguing natural pigment to a viable bio-manufactured compound. By integrating synthetic biology, fermentation engineering, and sustainable feedstocks, microbial systems can now deliver high yields with improved safety and environmental performance. Continued progress in regulatory design, host optimization, and process integration is expected to accelerate commercialization, enabling violacein to meet growing demand across healthcare, agriculture, food, and bio-based materials as a flagship example of next-generation microbial production.

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References

DOI

10.1016/j.bidere.2025.100043

Original Source URL

https://doi.org/10.1016/j.bidere.2025.100043

Funding information

This work was supported by the National Key R&D Program of China (2022YFC3401301), Jiangsu Agriculture Science and Technology Independent Innovation Fund Project (CX(24)3085), National Natural Science Foundation of China (22408164), Shandong Taishan Industrial Experts Program (202306155), Jiangsu Natural Science Fund for Distinguished Young Scholars (BK20220052), the State Key Laboratory of Materials-Oriented Chemical Engineering (No. SKL-MCE-23A10), and the National Spanish project MICODE (PID2020-114210RB-I00 MCIN/AEI).

About BioDesign Research

BioDesign Research is dedicated to information exchange in the interdisciplinary field of biosystems design. Its unique mission is to pave the way towards the predictable de novo design and assessment of engineered or reengineered living organisms using rational or automated methods to address global challenges in health, agriculture, and the environment.