PRELIMINARY STUDY OF THE NUTRITION OF THE CULTIVATED MUSHROOM

Abstract

Mushrooms are commercially grown uponl composts of horse manure. As the available supply of manure is becoming less, it is important to explain the wide difference between average and maximum yields. This requires a better knowledge of the nutrition of the cultivated mushroom than we now have. The first attempts to culture Agaricus campestris L. in media of known composition were made by Duggar (2), who made a series of cultures on gray filter paper to which were added various carbonaceous and nitrogenous cornpounds, along with a mineral nutrient solution. His successful cultures included those containing calcium hippurate, peptone, and casein; while the unsuccessful ones were upon the common sugars, starch, mannite, tartrates, lactates, urea, asparagine, ammonium salts, and nitrates. He concluded that the fungus could not utilize carbon in the form of sugars and organic acid salts, nor nitrogen in inorganic form. This conclusion is surprising in view of the general use of these compounds in culture media for fungi. Even the higher fungi have been grown upon such media, Lutz (6) having used a solution of xylose, maltose, ammonium salts, and minerals for hymenomycetes of several types. It is possible that Duggar's negative results were due in part to some adverse condition not easily observed rather than to the inability of the myceliun to develop upon simple nutrients. This possibility was considered in planning the present investigation. Hebert and Heim (4) asserted that calcium and potassium should be added to manures used in the commercial culture of mnushrooms, but supported the assertion only with analyses of mushrooms showing high contents of these elements. Later Hebert and Heim (5) reported that the composting of manure for mushroom culture was marked by losses in ammonia, organic acids, gums, cellulose, and xylan, and by increases in vasculose ( the black materials of the compost) and complex nitrogenous materials. They suggested that the nutrition of the mushroom was dependent upon a supply of the latter groups rather than of the former. Boyer (i), in a study of Agaricuts campestris, transferred his cultures from the original into manure, but said, Almost all organic materials and many inorganic substrata are good. He did not obtain growth upon blotting paper or cellulose; however, it was not stated what medium was used with these materials. Boyer did not mention the inorganic materials used, except to state that potassium nitrate did not improve the growth in