INTENSIFICATION OF THE FREEZE-THAW PRETREATMENT OF DISINTEGRATED POPLAR WOOD

This research was focused on the effect of water content in the cells of disintegrated Populus nigra L. on a freeze-thaw pretreatment method before an enzymatic hydrolysis. Two chipped and sieved fractions 2.5 mm and 0.7 mm and two milled fractions, characterized as 18 degrees SR (Shopper-Riegler index) and 37 degrees SR, of the disintegrated 5 years old poplar tree were used for our experiment. Glucose and xylose yields were measured after 24 and 48 hours of enzymatic hydrolysis with a 15% load of the enzyme measured to a total cellulose content. The influence of nine freeze-thaw cycles under - 20 degrees C and +20 degrees C was considered. The results showed that an increase in moisture content positively affects yields in all fractions but a desirable result was achieved mainly for the 0.7 mm fraction where the total yield increased by about 16%. More effective way is a finer wet beating of wood mass, while wood fibre receives moisture already in the technological process. The highest glucan conversion 51,74% and the total hemicelluloses conversion 47,72% was achieved for the finest fraction 37 degrees SR. The higher moisture content has a positive effect on the increase in the conversion of oligosaccharides, especially glucan, in chipped fractions.

Automated summary

This research focused on the effect of water content on the enzymatic hydrolysis of disintegrated Populus nigra L. The results showed that an increase in moisture content positively affects yields, particularly in the 0.7 mm fraction. Finer wet beating of the wood mass is a more effective method.