Indigo Dye: From Ancient Extraction to Green Biomanufacturing

Indigo, a historically significant blue dye widely used in textiles such as denim, was originally derived from plants. However, traditional extraction faced issues like low yield and high land use, while later chemical synthesis relied on toxic compounds, creating environmental and health concerns. Recently, microbial synthesis has emerged as a sustainable alternative, requiring only 10% of the time of plant-based methods and 80% less water than chemical production. Besides textiles, indigo is also applied in medicine, food, cosmetics, and semiconductors. This review covers the history, biosynthesis, detection, and diverse applications of indigo, addressing current challenges and highlighting its potential for eco-friendly dye manufacturing.