Mural Pigment Biodeterioration by Streptomyces Through Metabolic Pathway

Streptomyces are involved in the chromatic alteration of mural paintings due to the metabolic production of acids, in particular oxalic acid which reacts with the blue azurite pigment (basic copper carbonate) to form the green color of copper oxalate and acetic acid which turns the green mala-chite pigment and blue azurite pigment colors into green verdigris (basic copper acetate).This can result in a misleading interpretation about the original pigments used historically in mural paintings.

Automated summary

Streptomyces contribute to the color alteration of mural paintings by producing acids that react with certain pigments, resulting in green hues.