Used as a chromogenic substrate in microbiological assays for the detection of esterase enzyme activity, particularly in bacterial identification systems. When cleaved by specific esterases, it releases a blue-green insoluble indigo-type dye, enabling visual identification of microbial colonies on agar plates. Commonly applied in rapid diagnostic tests for pathogenic bacteria, including in clinical and food safety laboratories. Its long alkyl chain enhances lipid solubility, improving cell membrane penetration and substrate localization within microbial cells.