The Physiology of a Blue Stain Mold with Special Reference to Production of Ethyl Acetate

Abstract

SUMMARY A mold causing a blue stain of pine wood, identified as Endo-conidiophora moniliformis (Hedge.) Davidson, grows well in a solution of mineral salts, dextrose, and asparagin, when supplied with thiamin. It has a wide range of pH tolerance on this and other media, and an optimum temperature for mycelial growth of approximately 25° C. Considerable quantities of ethyl acetate as well as some ethyl alcohol are produced in the above solution, and the ester is formed also in malt extract solution, but no higher acetates were detected in cultures on either medium. The production of esters on the dextrose-asparagin medium is correlated closely with gain in dry weight by the fungus, a maximum for both being attained in about 12 days at a temperature of 20° C., following which the esters are gradually decomposed. E. moniliformis produces good growth, accompanied by varying amounts of ester, on the above medium when asparagin is replaced by any of several organic nitrogen compounds, notably urea, but in general neither growth nor ester production is pronounced when inorganic nitrogen sources are used. The dextrose-urea medium yields relatively large quantities of ethyl acetate. When urea is employed as the nitrogen source and other carbon compounds substituted for dextrose in the medium, it is found that soluble starch, mannose, cellobiose, and galactose permit good growth and good to poor ester production, and 2 pentoses good growth but no ester odor. Various 3-carbon intermediates in the usual chain of alcoholic fermentation support little or no growth and yield no detectable ester odor. Acetic acid in relatively low concentrations inhibits germination and growth of the organism, but ethyl acetate is utilized for the production of mycelium. Ethyl alcohol serves as an excellent carbon source for E. moniliformis with respect to both growth and production of ethyl acetate. The significance of these findings for the elucidation of the phase-sequence of ethyl acetate synthesis by E. moniliformis is discussed.