Kinetics of Fermentation of Indigofera tinctoria

Abstract

The kinetics of fermentation of indigofera tinctoria was studied in order to synthesize indigo, a natural blue dye. At first, the mature leaves were frozen to preserve the precursor and then fermented with distilled water. The fermentation was conducted at 3 varied temperatures of 30 40 and 50ºC until the reaction was completed. During the fermentation, indicant in leaves was changed to indoxyl, which then was oxidized to indigo. Subsequently, the amount of obtained indigo was measured by using UV-visible spectrophotometer. The results show that the reaction of indoxyl formation is endothermic reaction and has the order of 0.37. The equation of rate constant is k( h^-1 ) = (3.42 x 10¹¹ h^-1 )e^{8840.5 T} and the activation energy ( E_a ) is 17.6 kcal/mol.