Natural pigment extraction from five filamentous fungi for industrial applications and dyeing of leather

The present study aimed to evaluate and optimize the dyeing potential of fungal pigments for pre tanned leather samples. Five different water-soluble pigments were extracted from Monascus purpureus, Isaria spp., Emericella spp., Fusarium spp. and Penicillium spp., purified and used for dyeing processes. The effect of process parameters of dyeing such as pH, temperature, time duration, exhaustion of colour, shade brightness, colour intensity and fastness properties have been studied and the conditions were optimized. The results showed that the optimum concentration of the pigments were 6% on weight of leather. However, the optimum condition for dyeing was 70°C, at a pH 5, and the time duration 120min. The maximum uptake of pigments in the leather samples varied from 40% to 70±0.2%. The changes in shades of the samples were high in M. purpureus – red pigment and it compared with visual assessment data. The fungal pigments did not significantly alter the organoleptic properties of the leather sample.