Synthesis of Indigo: Indigo the dye used to color the Jeans, and can be made enzymatic ally by removal of side chains of Tryptophan, to give Indole, which can be dehydroxylated enzymatically, and then oxidized with oxygen to give Indigo. The presently used commercial process starts with highly toxic aniline and produces considerable amount of waste salts leading to waste disposal problems. The conventional method involves caustic fusion at two stages leading to the formation of large quantities of salts. The catalytic route selectively oxidizes indole, which is environmentally benign. Newer enzymatic process of conversion of glucose seems to be more promising as it is eco-friendly.