Indigo is a natural dye, extracted from Indigofera tinctoria which can be used for dyeing cloths or preparing hair oil. The cultivation of indigo is not labour intensive and the crop doesn’t need much protection. Indigo can be also cultivated as inter crop. The leaves can be harvested three times within a period of 9 months (1 main crop and 2 ratoon). It was aimed to improve crop yield through sustainable practices and extraction process to enhance quantity and quality of dyes for income generation among the farmers/land owners. The yield of fresh leaves per acre is around 3000 kg and the dye extracted per acre of fresh biomass is 12 kg. The cost of 1 kg of indigo dye is Rs.2500/-. Seeds of indigo are relatively expensive (Rs.350/kg seed) and a farmer can even market the seeds and earn profit.
As the indigo dye extraction needs aeration and in traditional method, this was done using human labours for mixing the fermented liquid. MCRC has developed a cyclic pedal type agitator and later a simple impeller type aerator. Since the cyclic pedal agitator was operated manually it is very slow and doesn’t agitate uniformly. These problems are addressed with the modified impeller type agitator. Apart from uniform agitation the release of dye is also rapid. Also, to improve the dye extraction, few microbes such as Pseudomonas spp., Trichoderma spp., Pythium spp. and Rhodospirillum rubrum and enzymes like amylase and cellulase were used in the fermentation process.