2.3 Conversion of indican to indoxyl
The indican solution was added to four times the volume of anhydrous
ethanol and stood overnight at room temperature for separation of
protein, starch and other macromolecules that are insoluble in ethanol.
The suspension was centrifuged at 11,510 × g for 5 min. The ethanol was
removed and the indican solution was concentrated using a rotary
evaporator. Cellulase was separated from Acremonium
cellulolyticus which has the activity of β-d-glucosidase was
added to concentrate for converse indican to indoxyl at 45 ℃ for 30 min.