The alc gene expression system is one of the most reliable chemically inducible gene switches for use in plants and fungus. This system relies on the ability of AlcR, a transcription factor, to bind to its target alcA promoter (alcA^P). Based on this, we have engineered Escherichia coli K-12 derivative DH5α and BL21 to induce expression of chromoproteins when AlcR binds to alcA^P in the presence of ethanol ^[1].