WOOD RESEARCH Volume 69, Number 2, 2024
ŠTEFAN BOHÁČEK, VLADIMÍR KUŇA, JOZEF BALBERČÁK, and ALENA JANDOVÁ

INCREASING THE EFFICIENCY OF ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSIC MATERIALS BY FREEZING PRETREATMENT

This paper describes the differences between the efficiency of enzymatic hydrolysis of selected lignocellulosic materials after pretreatment by cyclic freezing and thawing. It also discusses the analysis of the positive effect of alkaline conditions on pretreatment. The selected materials were Populus alba L., wheat straw from Triticum aestivum L. and Cannabis sativa. Three pretreatment methods were used to compare the efficiency of enzymatic decomposition of cellulose and cellulose accessibility. The best results show the wheat straw pre-treated at -20°C in the freezer with NaOH addition with a concentration of monosaccharides of 56.6 g.l-1 compared to initial hydrolysed material with a concentration of monosaccharides of 24.4 g.l-1. The results show better digestibility of grass compared to wood dendromass

WOOD RESEARCH Volume 65, Number 4, 2020
Pažitný Andrej, ALBERT RUSS, Boháček Štefan, MONIKA STANKOVSKÁ, VLADIMÍR IHNÁT, and Štefan Šutý

Effect of steam explosion on enzymatic hydrolysis of various parts of poplar tree

The effect of steam explosion on enzymatic hydrolysis of various parts of poplar tree (heartwood, sapwood and 1-year coppice) was investigated. These parts were milled, the obtained sawdust was chemically analysed and then steam explosion of 0.7 mm poplar particles at temperature of 205°C was performed. Concentration of monomers obtained after enzymatic hydrolysis was considered as the main indicator for cellulose accessibility. Analysis of high performance liquid chromatography showed that non-treated poplar sawdust does not enable sufficient cellulose accessibility, while excessively high temperature and rapid pressure release resulted in substantial breakdown of polysaccharides and lignin and formation of inhibitors. The concentration of monomers increased gradually in the order of coppice, sapwood and heartwood. Steam exploded heartwood gave the maximum monosaccharides concentration of 90.0 g.L-1 after 72 hours of enzymatic hydrolysis. However, glucose concentration culminated after 48 hours of this hydrolysis. This corresponds to the best holocellulose accessibility for enzymes. The maximum concentration of inhibitors (9.3 g.L-1) was determined for poplar coppice after 24 hours of enzymatic hydrolysis.