Screening of Natural Dyes from Filamentous Fungi and Leather Dyeing with Monascus purpureus Extract

Certain species of filamentous fungi produce coloured substances as secondary metabolites, which can be used as dyes for industrial applications. These natural dyes can be environmentally friendly alternatives to synthetic dyes, since they are extracted from sustainable sources with high yields, can be produced independently of seasonal effects, and no hazardous chemicals are used while they are produced. In this study, a screening of natural colourants from filamentous fungi was carried out by cultivation in liquid medium and further the Monascus purpureus extract was applied to leather dyeing. The efficiency of the dyeing was quantified through the remaining dye concentration in the wastewater by UV-vis spectroscopy, and the quality parameters of the leather samples were evaluated by the change of colour when they were exposed to light and heat. The absorption of Monascus dye into the leather was 70.6 +/- 2.7% when deacidification at pH5.0 was used. The dyed leather showed good penetration, colour homogeneity and heat fastness.