Copyright Interesting Engineering
The future of fashion may be brewing in a vat, thanks to researchers at the Korea Advanced Institute of Science and Technology (KAIST). Researchers have developed a sustainable method for creating and dyeing fabric using living bacteria. In this method, the living bacteria simultaneously grow fabric and dye it in every color of the rainbow. This approach offers an environmentally friendly alternative to the current textile industry’s chemical-heavy processes, which rely on polluting synthetic fibers and dyes. “The industry relies on petroleum-based synthetic fibers and chemicals for dyeing, which include carcinogens, heavy metals, and endocrine disruptors,” said San Yup Lee, senior author and biochemical engineer at KAIST. “These processes generate lots of greenhouse gas, degrade water quality, and contaminate the soil, so we want to find a better solution,” Lee added. Microbes as mini-factories Bacterial cellulose is a material emerging as a sustainable alternative to common petroleum-based textiles, such as polyester and nylon. It consists of pure, fibrous networks naturally produced by certain microorganisms during the fermentation process. Building upon the potential of bacterial cellulose, Lee’s team innovated by attempting to simultaneously create the fabric and dye it with vivid natural pigments. This was achieved by cultivating the cellulose-spinning bacteria (Komagataeibacter xylinus) alongside specialized color-producing microbes. The resulting microbial colors originated from two molecular families. First, the violaceins created cool tones, ranging from green to purple, while the carotenoids produced warm hues, from red to yellow. However, initial attempts to co-culture the cellulose-spinning bacterium (Komagataeibacter xylinus) and the color-producing bacterium (Escherichia coli) failed. This was because the species interfered with each other, resulting in poor cellulose production or a lack of color. Solving the microbial conflict To resolve this microbial conflict and achieve a full spectrum of colors, the researchers devised two strategies. For cool-toned violaceins, the color-producing bacteria were added only after the cellulose bacteria had already established growth, allowing both groups to perform their function successfully. In warm-toned carotenoids, cellulose was first produced, harvested, and purified, and then soaked in separate cultures that produced pigments. The implementation of these two specialized culturing methods resulted in bacterial cellulose sheets in colors ranging from purple to navy, blue, green, yellow, orange, and red. To assess the practical durability of the microbe-dyed fabric, the materials were subjected to washing, bleaching, heating, and exposure to strong acid and alkali solutions. The results were highly promising: most of the colors successfully retained their hues. Notably, the textile dyed with violacein-based pigments actually demonstrated better performance than synthetic dyes in washing tests. “Our work is not going to change the entire textile industry right now,” said Lee. “But at least we have proposed an environmentally friendly direction toward sustainable textile dyeing while producing cellulose at the same time.” Bringing these bacteria-based fabrics to market faces several challenges, which are estimated to take at least five years to overcome. The primary hurdles include scaling up production to industrial levels and competing economically with the low cost of existing petroleum-based textile products. Ultimately, the commercial success of this sustainable approach depends on a required shift in the consumer mindset to prioritize the environmental benefits and sustainability of the product over its potential higher price point. The study was published in the journal Trends in Biotechnology on November 12.
