Perspective pretreatment method of beech and poplar wood and wheat straw in 2G biofuel production processing

Andrej Pažitný,Vladimír Ihnát,Štefan Šutý,Štefan Boháček,Albert Russ

doi:10.36547/nbc.v19i1.581

Abstract

Monosaccharides such as glucose, xylose and arabinose are the main monomer units of which cellulose and hemicelluloses are composed. The cellulose and hemicelluloses content in many biomass species makes them suitable for 2G bioethanol production. Today, when 1G bioethanol production is closely monitored due to its enormous consumption of food raw materials such as wheat or corn grains, larger companies are gradually moving to pilot operations of 2G bioethanol production. However, cellulose and hemicelluloses contained in biomass are only very slightly accessible to enzymes used in 2G bioethanol production. Therefore pretreatment methods such as steam explosion are very suitable to use for fractionation of cell structure. In this paper, we tested the cellulose accessibility. We compared the cellulose accessibility of wheat straw particles with wooden particles obtained from beech and poplar. Particle size was less than 0.7 mm. We identified the optimal conditions of steam explosion pretreatment at reaction temperature of 200 °C for wheat straw, poplar and beech wood particles. The main indicator of accessibility was concentration of monomers obtained from enzymatic hydrolysis. The concentration of monomer was determined by high performance liquid chromatography. The experimental results showed different accessibility measure for each type of biomass species.

Highlights

Hexose and pentose sugars are suitable for bioethanol production, they are predominantly chemical components of starch, cellulose and hemicelluloses
The aim of this work was to study the chemical compositions of hydrolysates obtained after enzymatic hydrolysis of NP and steam explosion pre-treated (STEXP) samples of wheat straw, poplar and beech wood particles
According to several scientific papers (Kačík et al 2012; Zhao et al 2012; Kidalová et al 2015; Demčák et al 2017; Demčák et al 2019; Ibrahim et al 2020) it can be predicted that chemical structure of wheat straw, poplar and beech wood particles is mainly composed from cellulose, hemicelluloses and lignin

Summary

Introduction

Hexose and pentose sugars are suitable for bioethanol production, they are predominantly chemical components of starch, cellulose and hemicelluloses. Various suitable thermo-mechanical or thermohydro-mechanical pretreatment methods were published by several authors while thermochemical pretreatments tend to generate soluble sugars, degradation products of sugars and lignin, various other soluble components, and organic acids (Larsson et al 1999; Weil et al 2002; Kumar and Wyman 2008, 2009; Stankovská et al 2018; Xiong et al 2020) These methods are physicochemical pretreatment methods and they include steam explosion (STEX), ammonia fiber explosion (AFEX) and liquid hot water (LHW) pretreatment. Menardo's research team found that the intensity of pretreatment strongly affects the reduction of hemicelluloses at the level by about 15 % – 98 % between temperature ranging from 180 °C and 200 °C, the cellulose degradation is not affected by steam explosion pretreatment Exotic grass species such as miscanthus are cultivated solely for experimental purposes in Slovakia but they may be a good starting point for experimental design of pretreatment processes

Objectives

Results

Conclusion