Carbon Source and Micronutrient Requirements of the Aquatic Phycomycete, Catenaria anguillulae Sorokin

The requirements of the aquatic Phycomycete, Catenaria anguillulaewere analysed in liquid, shake cultures using a standardizedzoospore inoculum. Growth was determined by measuring mycelialdry weight and rate of production of titratable acid. D-glucose was the best carbon source and had an optimum concentrationof 166 mM of carbon for the medium used. When other carbon sourceswere supplied, only those related to glucose (fructose and mannose)or composed of glucose units with an alpha-linkage (maltose,glycogen, and starch) were readily utilized. Lactic acid wasdetermined qualitatively as an end-product of carbon metabolism. The optimum level of phosphate was 1.0 mM. The optimum concentrationof EDTA was 0.032 mM. Of the chelated cations included in themedium only the omission of iron, zinc, calcium, or magnesiumreduced growth. Concentrations of calcium below 0.4 mM and ofmagnesium below 0.2 mM were limiting; whereas, concentrationsof both ions up to 1 mM were non-toxic.