Team:Berkeley

The world consumes over 40 million kilograms of indigo annually, primarily for dyeing denim. Indigo is currently derived from petroleum using a high energy process, and commercial dyeing involves the use of reducing agents to solubilize the dye. The development of biosynthetic and bioprocessing methodologies for indigo dyeing could have environmental and economic advantages. By combining the biosynthesis of indigo and the use of the natural indigo precursor indican, we propose a more sustainable dyeing method as an alternative to chemically-reduced indigo in the large scale production of indigo textiles. We achieved in vivo indigo production in high titers, and efficient cleavage of indican using a non-native glucosidase. Inspired by natural systems, we isolated and characterized several plant and bacterial glucosyl transferases hypothesized to produce indican. Lastly, we compare the cost and environmental impact of our alternative with the present chemical process.

Many of the major advances in synthetic biology involve the ability to use microorganisms to synthesize compounds that are difficult or costly to produce chemically. Our team hopes to exploit this familiar application of synthetic biology for the production of indigo in E. coli.

Indigo, the dye used to make blue jeans around the world, is produced in quantities of tens of thousands of tons every year. The chemical process involves converting vast quantities of aniline into indigo. Because indigo is extremely insoluble in water, this product must be reduced to leuco-indigo, a white soluble substance, using sodium dithionite. By combining the biosynthesis of indigo and the use of the natural indigo precursor indican, we propose a more sustainable dyeing method as an alternative to chemically-reduced indigo in the large scale production of indigo textiles. We achieved in vivo indigo production in high titers, and efficient cleavage of indican using a non-native glucosidase. Inspired by natural systems, we isolated and characterized several plant and bacterial glucosyl transferases hypothesized to produce indican. Lastly, we compare the cost and environmental impact of our alternative with the present chemical process.