Indigo reduction by using microorganism: Comparison of reducing power between Dietzia sp. KDB1 and yeast (Saccharomyces cerevisiae)

This study aims to develop microbial indigo reduction by comparing the reducing power between Dietzia sp. KDB1 and yeast (Saccharomyces cerevisiae) at some reduction conditions. Oxidation–reduction potential (ORP), colour strength (K/S), and fluorescence intensity (FI) were applied to evaluate the reduction level as a function of microorganism concentration, pH, and glucose addition at 30°C. For both of the microbial systems, ORP decreased further −20 mV and K/S increased more than two by adding glucose. The reduction level became higher slightly by adding glucose, which played a role of metabolite in both of the reduction systems. Overall, reduction level of the yeast system was about a half of KDB1 system at the same reduction condition of 45 mL volume, 15 g/L natural indigo, 6 g/L reducing agents, pH 10.0, 30°C and glucose added.