STUDIES REGARDING THE PRETREATMENT WITH DILUTE ACID AND ENZYMATIC HYDROLYSIS OF WHEAT STRAWS FOR BIOETHANOL PRODUCTION

Abstract

In this paper there has been studied the influence of dilute acid pretreatment upon the production of reducing sugars from wheat straws during the enzymatic hydrolysis. The acid pretreatment was led at different temperatures of 120 °C, 130 °C, 160 °C and  170 °C and at different acid concentrations (4%, 1%, 0.5% and without acid) before the enzymatic hydrolysis stage. There have been selected an optimal period of time for the pretreatment of 40 minutes and a temperature of 160 °C, combined with a temperature of  48 °C for the enzymatic hydrolysis. In optimal conditions it was achieved an increasement of the reducing sugars content of 63.37% in comparison with the control sample to which no preliminary pretreatment was applied. The results obtained indicate the fact that the dilute acid pretreatment could increase the ethanol concentration at the end of the fermentation stage. In this case the maximum ethanol concentration of 1.118% vol. was obtained in 72 hours of fermentation with S. cerevisiae.