STUDIES REGARDING THE ALKALINE AND ALKALINE- PEROXIDIC PRETREATMENT INFLUENCE UPON THE REDUCING SUGARS QUANTITY OBTAINED FROM THE WHEAT STRAWS

Abstract

The main goal of this study was the evaluation of the reducing sugars quantity obtained from the wheat straws using the enzymatic complex Accellerase 1500 from Genencor in different conditions of alkaline and alkaline-peroxidic pretreatment. In the first phase we observed the induced modifications for the lignocellulosic materials at the cellulasic attack by the application of some alkaline treatments upon them. At the same time, we also observed the way in which the concentration of the alkaline solution influences the results of the enzymatic attack applied afterwards to the lignocellulosic materials. We used NaOH solutions at concentrations of 0,5 %, 1,0 %, 2,0 % and 4 %. From the data obtained we can conclude that the best results have been seen in the case of high concentration NaOH solutions. In the second phase we tried to obtain some results with the same efficiency as in the previous phase but by applying an alkaline pretreatment coupled with a peroxidic pretreatment. For this purpose we tested several hydrogen peroxide concentrations (of 0,5 %, 1,0 %, 1,5 % and 2 %) , keeping constant the concentration of the NaOH solution. The reducing sugars production was evaluated at the enzymatic hydrolysis periods of 24 and 48 h by the DNS method. The maximum content of reducing sugars from the analyzed raw material was obtained in the case of the combined alkaline-peroxidic pretreatment at 100^°C for 2h using  NaOH of 4 % concentration and H₂O₂  of  2,0 % concentration.