Ethanol fermentation of enzymatically hydrolysed pretreated wood fractions using Trichoderma cellulases, Zymomonas mobilis, and Saccharomyces cerevisiae

Abstract

Several highly cellulolytic fungi were initially screened for their cellulase and β-glucosidase activities. Culture filtrates from Trichoderma E58 demonstrated the highest β-glucosidase activity, giving a value of 1.0 IU/mg protein. A variety of different cellulose and pretreated wood substrates were hydrolysed by various cellulase preparations. The importance of the pretreatment conditions and ensuing chemical extractions of the cellulosic substrates was demonstrated by the range of sugar and ethanol values obtained after saccharification and fermentation of the liberated sugars. The rate of hydrolysis of the cellulosic substrate by Trichoderma E58 culture filtrates, concentrated culture filtrates, and whole cell cultures was compared. An ethanol value of 2.2% (w/v) could be obtained after hydrolysis of 5% Solka floe by concentrated culture filtrates of Trichoderma E58 and fermentation of the liberated sugars by Zymomonas mobilis or Saccharomyces cerevisiae.