Concurrent Production and Consumption of Ethanol by Cultures of Pachysolen tannophilus Growing on d -Xylose

Abstract

Growing cultures of Pachysolen tannophilus concurrently consumed and produced ethanol in the presence of substantial concentrations of d -xylose. Ethanol was also assimilated in the presence of other sugars, the amount depending on the sugar. Less ethanol assimilation occurred with d -glucose than with d -xylose. The rate of ethanol consumption decreased as the concentration of glucose was increased, but some consumption still occurred when 2% glucose was present. The rate increased with the amount of oxygen available to the culture when d -xylose or ethanol was the carbon source. In most instances, estimates of consumption were based on the extent of incorporation of 14 C from [1- 14 C]ethanol into trichloroacetic acid-insoluble material. The results are pertinent to the use of P. tannophilus for the production of ethanol from d -xylose.