Growth-coupled microbial biosynthesis of the animal pigment xanthommatin

Engineering heterologous natural product pathways in bacteria has achieved broad success but most approaches suffer from low initial production levels that require extensive, resource-heavy iterative strain optimization. Xanthommatin is a structurally complex, color-changing animal ommochrome with material and cosmetic applications, yet production in microbial cell factories has been difficult. Here, we introduce a growth-coupled biosynthetic strategy involving a feedback loop where an excised one-carbon (C1) moiety is used as a driver of bacterial growth, simultaneously boosting bioproduction of the target compound. This broadly applicable, plug-and-play strategy is illustrated by enabling xanthommatin biosynthesis in a 5,10-methylenetetrahydrofolate auxotroph of the platform soil bacterium Pseudomonas putida. In this design, formate released during xanthommatin production relieves the C1 deficiency, thereby effectively coupling bacterial growth to pigment synthesis. Adaptive laboratory evolution streamlined xanthommatin's gram-scale bioproduction from glucose, establishing C1 restoration as a general biosynthetic approach to accelerate the engineering of natural product biosynthesis in bacteria.