Biosynthetic indigo dye for denim is chemical and petroleum-free - Springwise

The dye has potential for further applications in food and cosmetics

Indigo synthetic, Dye content 95 482-89-3

Indigo synthetic, Dye content 95 482-89-3

Green-route-blue-dye

What are biosynthetic dyes & could they replace the toxic petroleum

Greener Jeans Chemistry Article for Students

Study on structure and properties of natural indigo spun-dyed

Full article: Identification of Indigo Dye (Indigofera tinctoria

Discharging of Indigo Dye Natural Dye: Experiments and Results

How bacteria can replace oil to make denim's indigo dye