The Phycomycete Catenaria anguillulae: Growth Requirements

SUMMARY: The physical factors and nitrogen requirements for the growth of the aquatic phycomycete Catenaria anguillulae in liquid shaken cultures from measured zoospore inocula were examined. Growth was determined by measuring mycelial dry weight and rate of titratable acid production. The optimum pH range for growth was pH 8.2 to 8.7. The toxicity of the pH indicators used was assessed. The optimum temperature for growth was 25°. The organism was highly aerobic. Inorganic nitrogen sources were not utilized. When organic nitrogen sources were supplied individually, L-aspartic acid, L-asparagine, L-glutamic acid, L-arginine, DL-citrulline and L-ornithine were utilized. Asparagine was the best single source. When the N sources were supplied as Difco vitamin-free Casamino acids, only lysine, methionine and arginine were utilized during the lag phase. During the more rapid phase of growth, all of the amino acids detected in the Casamino acids were utilized. When the vitamin-free Casamino acids were replaced by an equivalent amino acid mixture, the subsequent decrease in yield was not corrected by adding NaCl, oleic acid or stearic acid. The optimum concentrations of various N sources were determined. The medium finally evolved contained L-asparagine + L-lysine as N sources.