A strain of Polyporus sulfureus from the collection at the University of Missouri at Rolla was used in this investigation. Organisms of this genus have been reported to produce eburicoic acid in good yield and this was confirmed for the organism used in this study by the isolation and identification of eburicoic acid from the mycelium. Growth studies of this organism showed that 4% malt extract is a better medium than synthetic media containing asparagine, nitrate or nitrate plus 0.5% yeast extract as nitrogen sources. An examination of the pH of the culture medium led to the conclusion that regardless of whether or not the medium was buffered good growth of the organism caused a decrease in the pH of the medium. Eburicoic acid present in the mycelium of this organism did not account for this decrease in the pH of the medium. Conventional manometric techniques were used for the respiratory studies. Substrates labeled with ¹⁴C were used as a supplement to this technique. Results from these experiments indicated that this organism cannot utilize glucose directly as an energy source. Acetate and succinate stimulated oxygen uptake of the mycelium of this organism whereas pyruvate inhibited it. The reason for pyruvate inhibition of respiration in this organism is not known but certain possible causes are discussed. The R.Q. value for P. sulfureus was about 0.8. This suggested that an endogenous storage material of the oxidation state of lipid was bing utilized rather than carbohydrates. Results from work with ¹⁴C labeled glucose indicated that the pentose cycle in this organism had preference over the glycolytic pathway --Abstract, page ii-iii
