Abstract

Fungal pigments are used in diverse industries such as food, pharmaceuticals, textile, among others. The need of new organic pigments involves the search for new microbial sources. In this study, three fungal strains isolated from Quercus sp andLarrea tridentata were morphological, physiological and molecularly characterized. Different temperatures (8, 16, 20, 24 and 32°C) and pH (4, 6, 7, 8 and 10) levels were tested to determine the best conditions to produce a fungal pigment under submerged and solid state fermentation. The three strains were genotyped by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), random amplified polymorphic DNA (RAPD), inter-transcript spaces (ITS) and intergenic spaces (IGS) with the object to eliminate duplications. The strains were identified according to their morphology as Penicillium purpurogenum (GH2) and Penicillium pinophilum (EH2 and EH3). It was found that at submerged state fermentation to 24°C and pH 10, the three strains produced pigments, but P. purpurogenum GH2 strain produced the highest amount of pigments (1.25 U). According to the molecular analysis, it was found that all strains were different. This is to our knowledge the first report on characterization of fungal strains isolated from the Mexican semi-desert which have potential for pigment production.

Key words: Penicillium purpurogenum, Penicillium pinophilum, intergenic spaces (IGS), inter-transcript spaces (ITS), pigments, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), submerged and solid state fermentation.

Abbreviation

PCR-RFLP, Polymerase chain reaction-restriction fragment length polymorphism; RAPD, random amplification of polymorphic DNA; ITS, internal transcribed spaces; IGS, inter-genetic spaces; PDA, potato-dextrose agar; MSA, malt extract agar; SmF, submerged fermentation; SSF, solid state fermentation; AME,agar-malt extract.