The Extent of Acetate and Ethanol Oxidation by Euglena gracilis

Abstract

Euglena gracilis utilizes acetate and ethanol as energy and carbon sources. The O2 consumption due to acetate was equivalent to a 42% oxidation of the available acetate. CO2 production in the presence of acetate was consistent with the assumption that acetate is simultaneously oxidized and converted to carbohydrate. Addition of ethanol resulted in an O2 consumption equivalent to a 39% oxidation of this substrate. The CO2 production due to ethanol was 0.93 ([mu]mole per [mu]mole of ethanol, more than double the amount predicted if carbohydrate is the sole synthetic product of ethanol metabolism. Conditions known to change the rate of respiration, such as growth media, incubation pH, and the adaptation to acetate of ethanol grown cells, had no effect upon the extent of ethanol and acetate oxidation.