Abstract

In this work Talaromyces australis and Penicillium murcianum pigment production in liquid cultures and the cytotoxic effect of such pigments on skin model cells were studied. Response surface methodology (RSM) was used to optimize culture conditions aiming to increase pigment production in malt extract and peptone-glucose-yeast extract medium. Cytotoxicity of fungal pigments and also from lixiviates of wool fabrics dyed with T. australis and P. murcianum pigment was evaluated on mammalian cell lines HEK293 and NIH/3T3. Results showed that variations on initial pH, NaCl and peptone, resulted in increments up to 188.2% for red pigment of T. australis and 107.4% for yellow pigment of P. murcianum, regarding non-optimized conditions. Tested fungi also showed great differences in culture conditions for the maximum pigment production, with P. murcianum requiring an alkaline medium (initial pH 9) supplemented with NaCl and T. australis an acidic medium (initial pH 5) without addition of salt. The cytotoxicity assays provided evidences on the safe nature of these natural pigments when used for textile applications. The cytotoxicity assay showed that the threshold of toxicity, given by the lowest IC50 value (0.21 g L-1) was more than double of the concentration of pigment required to dye the wool samples. In addition, cytotoxicity of lixiviates depicted no toxic effect over tested cells.