Growth Factors for Polyporus Schweinitzii. The Identification of Ferulic Acid as a New Cofactor

SUMMARY

The beneficial effect on the growth of Polyporus schweinitzii of natural materials such as yeast extract or distillers solubles in a basal medium of dextrose, mineral salts, “vitamin free” casein hydrolysate, vitamins and purine and pyrimidine bases, is mainly because of the presence in the natural materials of ferulic, linoleic, oleic, palmitic, and stearic acids. The growth-promoting activity of ferulic acid showed considerable structural specificity; isoeugenol was about as active as ferulic acid but was not identified in the natural materials. Of the fatty acids, linoleic was the most important. Growth in the basal medium supplemented with a combination of ferulic acid, isoeugenol and a mixture of the four fatty acids, approached that in the same medium supplemented with yeast extract. Exposure of cultures to laboratory light for 1–2 hr on the 3rd, 5th, and 7th day after inoculation affected growth as compared to growth in darkness; the effect varied with the supplements added to the basal medium. Chemical procedures in the isolation and identification of ferulic acid and the fatty acids from distillers solubles are briefly described.