Will tomorrow’s pigments be bacterial?

Produced via fermentation, bacterial-derived pigments could offer a sustainable, biodegradable alternative to synthetic dyes, according to a study published in Frontiers in Bacteriology. Sourced from a vast array of microbial strains, they provide a broad chromatic palette, even if blue and green shades remain somewhat scarcer. Beyond their primary colouring function, compounds such as carotenoids or violacein exhibit antioxidant, photoprotective, or antimicrobial properties capable of delivering added functionality to formulations.

Pigment-producing bacteria of Trans-Himalayan origin (strains belonging to the genera Iodobacter,Streptomyces, Janthinobacterium, Kocuria, etc.). Reproduced from Kumar et al. (2022), under CC BY license.

For many of these microorganisms, synthesising these colourful secondary metabolites serves as a fundamental adaptation strategy. This is notably true in the high altitudes of the Himalayas, where unique microbial communities secrete these pigments to survive extreme environmental conditions.

Although a few molecules are already commercially available (riboflavin, alpha-carotene, astaxanthin), large-scale industrial adoption is still hindered by low yields, high production costs, and stringent regulatory safety requirements. However, optimisation levers are rapidly expanding: genetic and metabolic engineering (CRISPR/Cas), combined with artificial intelligence and machine learning, are accelerating yield rates. Concurrently, the screening of extremophile strains ensures exceptional stability, while upcycling agricultural by-products as fermentation substrates lowers overall expenditure.

Furthermore, advances in genetic engineering have enabled the synthesis of a spectrum of red, bright yellow, pale yellow, and orange hues from Streptomyces coelicolor, a natural producer of a blue pigment – opening fascinating prospects for the products of tomorrow.