Synthetic Biology–Driven Melanin Deposition for Wood Coating

Wood, a lightweight, strong and versatile biopolymeric material, is widely used in construction, packaging and emerging functional applications. Beyond its structural and functional roles, wood is often modified with colored coatings to enhance its visual appeal and expand its design versatility. Conventional dyeing and painting methods rely on the use of synthetic chemicals, which consume large volumes of freshwater for their production. Bio-based pigments have been explored as sustainable alternatives, yet their extraction competes with agricultural resources and often results in limited scalability. Here, we report a bioinspired approach for wood coloration via in situ melanin biosynthesis. Escherichia coli engineered to express tyrosinase catalyzed the conversion of tyrosine into melanin directly on wood substrates, yielding a uniform black coating. The coated wood substrates were evaluated for the morphological characteristics through scanning electron microscopy, while FTIR, XRD, and XPS analyses revealed their chemical modifications. The melanin layer conferred moisture retention and photothermal responsiveness without compromising compressive strength, establishing a sustainable strategy for eco-friendly and functional wood coloration. By bridging synthetic biology with materials, this approach paves the way for next-generation wood-based materials in sustainable architecture, decorative design, and thermal management.