Color Stains on Paper: Fungal Pigments, Synthetic Dyes and Their Hypothetical Removal by Enzymatic Approaches

Fungi are the main contaminants of books and archival documents. In addition to their degrading power, offered by various types of lignolytic and cellulolytic enzymes, they can also hue the surface of the paper through the production of pigments. The fungi on paper release various types of pigments belonging mostly to two chemical groups (polyketides and carotenoids), which cause unpleasant anaesthetic stains. The paper surface can also be hued with several synthetic colors, which are part, for example, of stamps and inks. These synthetic colors could be degraded by lignin-modifying enzymes (LMEs) and also by dye-decolorizing peroxidases (DyPs). Therefore, the mechanism of action of LEMs and DyPs is illustrated. Moreover, we have examined the potentiality of LEMs and DyPs to remove the synthetic stains and also their hypothetical application in order to clean the fungal hues from the paper surface. Our review article, using the enzymatic removal parallelism between fungal and synthetic pigments, would like to show prospective solutions to this arduous problem.