X-Gal (5-bromo-4-chloro-3-indolyl-β-D-galactoside) is a histochemical substrate for β-galactosidase. This substrate yields a blue precipitate upon hydrolysis, making it suitable for use in immunoblotting or immunocytochemical assays. Bacteria containing active β-galactosidase produce blue colonies when grown on plates containing X-Gal. X-Gal is supplied as white crystals and is soluble in dimethylformamide.

Primary applications
• Blue-white screening—detect functional β-galactosidase (reporter gene expression)
• Histochemical detection of β-galactosidase activity in fixed tissues
• X-gal overlay assay

Find the media format that fits your needs
We offer many ready-to-use media formulations, such as LB Broth, Terrific Broth or S.O.C recovery medium.
We also offer IPTG for blue-white screening.
Explore other media formats for bacterial growth.