PHYSIOLOGY OF WOOD-ROTTING BASIDIOMYCETES: IV. RESPIRATION OF NON-PROLIFERATING CELLS OF POLYPORUS PALUSTRIS

Abstract

For manometric studies of respiration, small, whole mycelial pellets of Polyporus palustris grown in submerged (shake) culture were much superior to fragmented mycelium. The rates of endogenous and of exogenous respiration were dependent, in part, upon age of culture, and were maximal at pH 5.5. The endogenous respiration was high but could be reduced by starvation (aeration in a non-nutrient medium), permitting measurement of exogenous respiration upon the addition of oxidizable substrate. Of the carbohydrates studied, xylose, glucose, galactose, and sucrose were the most stimulative to aerobic respiration; rhamnose, melezitose, and lactose either were not oxidized or showed only slight stimulation. The alcohols methanol, ethanol, glycerol, and propylene glycol were readily utilized; inositol was oxidized to a lesser degree. The sugar alcohols mannitol, sorbitol, and adonitol were mildly stimulative; the effect of dulcitol was dependent upon its concentration. The fatty acids acetate and caprylate were much more readily utilized than butyrate. Salts of other acids— oxalate, pyruvate, lactate, and fumarate—were oxidized to about the same extent as butyrate. Non-proliferating cells of P. palustris had a definite anaerobic metabolism and fermented glucose with production of carbon dioxide and small amounts of acid(s). In air, oxidative assimilation of glucose was high (79–91%); endogenous respiration apparently was not suppressed during assimilation.