Used as a chromogenic substrate in molecular biology and microbiology for the detection of β-D-xylosidase enzyme activity. When the enzyme cleaves the glycosidic bond, it releases an insoluble blue-colored indigo dye, enabling visual identification of enzyme-producing microorganisms or gene expression in recombinant systems. Commonly applied in agar-based assays and histochemical staining to screen clones or identify specific bacterial species. Its specificity makes it valuable in diagnostic media and enzymatic studies where selective detection is required.