GROWTH AND MYCELIAL STRAND PRODUCTION OF RIGIDOPORUS-LIGNOSUS WITH VARIOUS NITROGEN AND CARBON-SOURCES

Growth and differentiation of mycelial strands in Rigidoporus lignosus have been shown to depend on suitable combinations of the pH of the m edia and the nature of the nitrogen and carbon sources. Amino acids as sole nitrogen sources gave rise to vegetative mycelium. At pH 4.5, gr owth and mycelial strand differentiation required asparagine, as the f ungus failed to grow in the absence of this amino acid. However, at pH 6, differentiation of strands occurred appreciably in asparagine-defi cient media, suggesting a close balance between pH and amino acid requ irements. Ammonium was required for strand differentiation, while nitr ate, as a sole nitrogen source, maintained the fungus undifferentiated . Of the carbohydrates tested, only glucose, fructose and mannose supp orted strand differentiation. Starch was found to be particularly effe ctive in promoting growth of vegetative mycelium. Strand differentiati on required more specific conditions than growth of the vegetative myc elium.