Technologies - Natural Indigo Dye Extraction

   Natural Indigo Dye Extraction

Cultivation of Indigo for extraction of dye is an age old practice in India. It is cultivated both under irrigated and dry conditions, in different types of soils like red, black, sandy and clayey soils. The crop yield and dye content varies according to the soil type, irrigation and climatic conditions. The crop once sown will give one main crop and two ratoon crops. Both the main crop and the ratoon crops give the same yield. During winter when dew falls the dye content is very low and the extraction goes uneconomical. 

Seed germination studies were conducted with indigo seeds using different treatments such as CPP-82%, BD-74% etc. Seeds were sown in one acre area and repeated extractions carried out from 110 days-old plants treated with Pseudomonas and cellulase enzyme. An improved agitator was also being fabricated with modifications. For maximum extraction of pigments (dyes) different methods were tried such as treating the plants with Pseudomonas, Trichoderma and cellulose enzymes, modification of indigo agitator (plastic propeller) and soaking setup, pH adjustment (6.0 and 7.0), chapping and smashing of indigo plants (2cm) through briquetting machine, oxidation etc. The modified process involved overnight fermentation of harvested indigo plant biomass using bacteria in specially designed cement moulded ring tank after which the plant debris is removed and the ferment liquid oxidized using specially designed mechanical agitator. The precipitate d indigo settle down at the bottom of the tank as the slurry is collected, 
boiled, filtered and sun dried as indigo cake. This package of simplified technology also could be transferred to villages so as to benefit women and traditional farmers.

Organic Cultivation of Indigo - Field Trails at V.K. Badi

Indigo Tank Construction and fabrication new agitator setup