Orange G is a monoazo dye that combines with proteins to produce Rayleigh scattering spectrum. It is used as stain in microscopy and as a pH indicator.

Orange G dye was incorporated in white rot fungal culture media to study the decolorization of azo dyes by the fungi.

The susceptibility of individual bacterial cells to the antibiotic was assessed by differential staining using the metachromatic dye, acridine orange. Exponential phase cultures were exposed to the minimum bactericidal concentration of gentamicin and analysed at regular intervals over 90 min. Within 60 min of exposure to the drug, two sub-populations of organisms could be distinguished in cultures by their different acridine orange-associated fluorescence emissions of 550 nm and >550 nm. 

ORANGE G Indicator For microscopy