1. Chemical and bioactivity profiling of extractives from tropical wood residues : Ipe, Merbau, and JatobaAmina Selmanović, Wojciech Pajerski, Kamil Drożdż, Monika Brzychczy-Wloch, Andreja Kutnar, Rene Alexander Herrera Diaz, 2026, original scientific article Abstract: Wood residues and by-products from the furniture industry represent an underutilized resource with strong potential for integration into circular economy strategies. Extractives derived from these materials are rich in bioactive compounds, making them attractive candidates for bio-based product development. Although the functional properties of wood extractives are well recognized, their systematic recovery and characterization remain insufficiently explored in the context of green chemistry and sustainability. This study investigated the chemical composition and bioactivity of extractives obtained from industrial residues of three tropical hardwoods: Ipe (Handroanthus spp.), Merbau (Intsia spp.), and Jatoba (Hymenaea courbaril). Extractives were obtained via Pressurized Solvent Extraction (PSE) and characterized using gas chromatography (GC-FID and GC-MS). Ultrasound-assisted extraction (UAE) was subsequently applied for bioactivity evaluation. Green metrics, including the simple E-factor (sEF) and unit energy (UEC), were calculated to assess basic environmental efficiency. Gravimetric results showed a predominance of hydrophilic fractions (up to 97 % in Merbau), with major constituents including phenolics, fatty acids, flavonoids, and resin acids. Merbau and Jatoba extracts exhibited strong antioxidant capacity (IC50 < 75 μg/mL), while preliminary antimicrobial screening indicated selective activity of Merbau and Ipe against Staphylococcus aureus and Staphylococcus epidermidis, with Ipe also inhibiting Streptococcus pyogenes. These findings highlight tropical wood residues as renewable sources of bioactive compounds and support their valorisation in sustainable bio-based applications.
Keywords: tropical wood valorisation, green extraction, antioxidant capacity, bioactivity
Published in RUP: 26.01.2026; Views: 413; Downloads: 2
 Full text (1,84 MB)
This document has more files! More... |
2. Photochemical behavior of colloidal lignin particles under controlled UV exposure : balancing self-stabilization and degradationJulia Tomasich, Rene Alexander Herrera Diaz, Anna Malgorzata Sandak, Michael Harasek, Stefan Beisl, Oihana Gordobil, 2025, original scientific article Abstract: Colloidal Lignin Particles (CLPs), with their polyphenolic structure, are promising sustainable alternatives to chemical UV filters. This study investigates the photochemical behavior of CLPs under ultraviolet irradiation synthetized from five different technical raw lignins (Alkali, Organosolv, two Enzymatic Hydrolyzed and Softwood Kraft Lignin) via solvent-shift procedure. The suspensions were irradiated using a self-developed UV-pen set-up and a commercially available UV chamber, enabling controlled UV exposure over time. Variations in the physicochemical properties of irradiated colloidal lignin particles were characterized by Multi-Angle Dynamic Light Scattering (MADLS), Fourier Transform Infrared Spectroscopy (FTIR) coupled with chemometrics, UV–Vis spectroscopy, and High-Performance Size Exclusion Chromatography (HP-SEC). CLPs exhibited comparable responses after 14 days of UV exposure, with alterations in particle chemistry, particularly in the formation of new functional groups and molecular rearrangement. Moreover, the photochemical stability of CLPs was found to be highly dependent on both their concentration and the nature of the dispersion medium (aqueous, hexane-based, and solid-state). At higher concentrations (1.8 mg/mL), CLPs demonstrated effective self-stabilization, while lower concentrations led to rapid degradation, resulting in the disappearance of particles and the formation of low-molecular-weight fragments. Additionally, Minimal photochemical changes were observed in non-aqueous or solid-state environments due to restricted molecular mobility. These findings provide valuable insights into the degradation pathways and stability across different environmental contexts, which can contribute to understanding the potential environmental impact of CLPs in aquatic ecosystems.
Keywords: biobased materials, lignin colloidal particles, photodegradation, UV-irradiation, spectroscopy
Published in RUP: 09.09.2025; Views: 658; Downloads: 6
Full text (4,47 MB)
This document has more files! More... |
3. Hybrid approach for wood modification : characterization and evaluation of weathering resistance of coatings on acetylated woodAnna Malgorzata Sandak, Edit Földvári-Nagy, Faksawat Poohphajai, Rene Alexander Herrera Diaz, Oihana Gordobil, Nežka Sajinčič, Veerapandian Ponnuchamy, Jakub Michal Sandak, 2021, original scientific article Keywords: wood modification, natural weathering, acetylation, coatings, service life performance, aesthetic
Published in RUP: 04.06.2021; Views: 3823; Downloads: 32
 Link to full text |
4. Characterization of heritage objects with NIR hyperspectral imagingJakub Michal Sandak, Anna Malgorzata Sandak, Lea Legan, Klara Retko, Maša Kavčič, Janez Kosel, Faksawat Poohphajai, Rene Alexander Herrera Diaz, Veerapandian Ponnuchamy, Nežka Sajinčič, Črtomir Tavzes, Polonca Ropret, 2021, published scientific conference contribution abstract Keywords: hyperspectral imaging, cultural heritage, painted beehive panels
Published in RUP: 06.05.2021; Views: 4164; Downloads: 12
Link to full text |
5. |
6. Impact of drying process on kraft lignin : ligninwater interaction mechanism study by 2D NIR correlation spectroscopyOihana Gordobil, Rene Alexander Herrera Diaz, Faksawat Poohphajai, Jakub Michal Sandak, Anna Malgorzata Sandak, 2021, original scientific article Keywords: hardwood kraft lignin, drying temperature, DVS, NIR spectroscopy, 2D-COS
Published in RUP: 06.05.2021; Views: 3868; Downloads: 11
Link to full text |
7. Nondestructive evaluation of heritage object coatings with four hyperspectral imaging systemsJakub Michal Sandak, Anna Malgorzata Sandak, Lea Legan, Klara Retko, Maša Kavčič, Janez Kosel, Faksawat Poohphajai, Rene Alexander Herrera Diaz, Veerapandian Ponnuchamy, Nežka Sajinčič, Oihana Gordobil, Črtomir Tavzes, Polonca Ropret, 2021, original scientific article Keywords: hyperspectral imaging, cultural heritage, nondestructive testing, surface characterisation, painted beehive panels
Published in RUP: 06.05.2021; Views: 2770; Downloads: 49
Link to full text |
8. Fractionation of lignin using organic solvents : a combined experimental and theoretical studyVeerapandian Ponnuchamy, Oihana Gordobil, Rene Alexander Herrera Diaz, Anna Malgorzata Sandak, Jakub Michal Sandak, 2020, original scientific article Keywords: hardwood kraft lignin, fractionation, chemometrics, density functional theory, hydrogen bonds, noncovalent interactions
Published in RUP: 02.12.2020; Views: 3405; Downloads: 36
Link to full text |
9. Hydrophobization and photo-stabilization of radiata pinewood : the effect of the esterification on thermal and mechanical propertiesRene Alexander Herrera Diaz, Oihana Gordobil, Pedro L. Hoyos-Martinez, Anna Malgorzata Sandak, Jalel Labidi, 2020, original scientific article Keywords: wood esterification, fatty acids, hydrophobicity, photo-stability, mechanical properties, thermal oxidation
Published in RUP: 02.12.2020; Views: 4057; Downloads: 36
Link to full text |
10. |
