Addition of Indigofera tinctoria leaf powder on indigo fermentation fluids prepared with sukumo (composted Polygonum tinctorium leaves)
Sukumo (composted leaves of Polygonum tinctorium) is a Japanese traditional method to concentrate natural indigo dye. It also possess substrate and a bacterial seed necessary for the next fermentation step, where the insoluble Indigo will be reduced into soluble leuco-indigo and used to dye fabrics. The reduction can take from a couple of days to weeks to start. Additives have shown to be efficient in improving the reduction conditions, therefore we used the powder of Indigofera tinctoria (another indigo bearing plant) to help decrease the initiation time of the reduction.