StexFur

Project summary

The objective of the research is to carry out interdisciplinary non-economic industrial research that will combine the fields of chemical engineering, materials science, and industrial biotechnology, as well to promote knowledge transfer through the development of an innovative technological solution for furfural production that can be integrated into a modern biorefinery system.

The scientific goal of the project is to identify the best steam explosion process parameters that provide the best way to selectively separate C5 oligosaccharides from oat hulls to later hydrolyse them into furfural using functionalized lignin-based biochar, formed from the solid residue of the enzymatic hydrolysis through pyrolysis, as well as to ensure the highest conversion rate of C6 oligosaccharides into glucose for fatty acids production.

Call: Specific Objective 1.1.1 “Strengthening of Research and Innovation Capacities and Introduction of Advanced Technologies in the Common R&D System” of the European Union's Cohesion Policy Programme for 2021-2027.

Activity: 1.1.1.9 “Post-doctoral Research”.

Project duration:  36 months.

Total eligible costs of the project: 184 140 EUR, including funding from the European Regional Development Fund in amount of 85 % – 156 519 EUR.

Project partners:

• Leading partner/coordinator: Latvian State Institute of Wood Chemistry.
• Cooperation partner: Uppsala BioCenter of Swedish University of Agricultural Sciences, Department of Molecular Sciences.

Place of implementation: Latvian State Institute of Wood Chemistry

Project implementation

30.04.2026.

Project progress report for the period from 01.01.2026 to 30.04.2026.

• Investigation of the STEX process. Planned experiments were carried out using the steam explosion (STEX) equipment to determine the influence of catalyst presence and process parameters on the yield of xylooligosaccharides. Experiments were conducted at two temperatures (170 and 210°C) using two catalysts (NH₄H₂PO₄ and NH₄HSO₄), with catalyst amounts ranging from 1 to 5% based on the oven-dry mass of oat husks. To evaluate catalyst efficiency, experiments under the same conditions were also performed without catalyst. Two types of samples were obtained (a xylooligosaccharide-containing solution and a solid residue), which were undergo more detailed investigation.
• Enzymatic hydrolysis. Research on glucose production from the solid residue after the STEX process has been started. A cellulase enzyme complex from Novonesis is being used as a catalyst in the process.

• Characterization of the obtained products. The method for oligosaccharide (OS) identification and quantification using the HPLC-ELSD system was improved. This method includes the quantification of xylooligosaccharides (XOS-3 to XOS-6) and cellooligosaccharides (COS-2 to COS-5). In parallel, the method for determining degradation products using the HPLC-RID system was also improved. In addition to the quantification of organic acids (formic acid, acetic acid, levulinic acid) and furan-type compounds (5-hydroxymethylfurfural, furfural, and 5-methylfurfural), now this method also enables quantification of arabinose, glucose, xylose, COS-2, and XOS-2. Both methods were used for the analysis of the obtained liquid fraction in the STEX process. The solid residue after the STEX process was analysed according to the NREL/TP-510-42618 protocol.

   

30.12.2025.

Project progress report for the period from 01.07.2025 to 31.12.2025.

• Determination of the chemical composition of oat husks. During this phase of the research project, the chemical composition of the raw material was determined in order to enable evaluation of the efficiency of the processing methods used in the study with respect to the production of target products. The composition of the raw material was analysed according to the TAPPI 204, NREL/TP-510-42618, and NREL/TP-510-42622 protocols.
• Investigation of the STEX process. Operation of the steam explosion (STEX) unit was established. Initial experiments were carried out to determine the oat husk particle size and initial moisture content suitable for processing. The maximum allowable storage time of the prepared raw material prior to implementation of the STEX process was determined. The procedural steps required to avoid erroneous data acquisition were refined. Preliminary experiments were conducted to identify the operational boundaries of the STEX process, within which subsequent optimization of processing conditions will be performed. NH₄HSO₄ was used as a catalyst.
• Characterization of the obtained products. An HPLC-ELSD method was developed for the identification and quantification of xylooligosaccharides in condensates obtained from the STEX process. The obtained condensates were analysed using HPLC-ELSD and HPLC-RID methods. Initial data were obtained on the content of xylooligosaccharides and other biomass degradation products in the condensates. The chemical composition of the solid residue obtained after the STEX process was also determined.

01.07.2025.

The project was begun.