Effect of pH on the radial growth rate and pigment production of two strains of Pycnoporus.

The genus Pycnoporus includes saprophytes and basidiomycetes fungi common in tropical and subtropical areas of the world. These fungi have a great potential in the production of metabolites. In this study, two strains of Pycnoporus spp HEMIM-55 and 80 were investigated. The effect of pH culture media (4.5, 5.5, 6.5, 7.5 and 8.5) on radial growth rate and pigment production of two strains of Pycnoporus HEMIM-55 and 80 were evaluated. Optimal pH value for growth and pigmentation were 5.5 and 6.5. HEMIM-80 strain showed higher pigment coloration than HEMIM-55, but HEMIM-55 had a faster radial growth rate. In general, cells internal pH is neutral, but microorganisms have a mechanism for controlling inlet and outlet protons and cations flow, throughout the membrane, then they are capable to develop over different pH range. The culture media pH is an important factor for growth and pigment production in these fungi, however, the best pH conditions responsible for growth and pigment formation for Pycnoporus have been scarcely investigated.