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Enhancing Sustainability and Antifungal Properties of Biodegradable Composites: Caffeine-Treated Wood as a Filler for Polylactide
This study investigates the suitability of using caffeine-treated and untreated black cherry (Prunus serotina Ehrh.) wood as a polylactide filler. Composites containing 10%, 20%, and 30% filler were investigated in terms of increasing the nucleating ability of polylactide, as well as enhancing its resistance to microorganisms. Differential scanning calorimetry studies showed that the addition of caffeine-treated wood significantly altered the crystallization behavior of the polymer matrix, increasing its crystallization temperature and degree of crystallinity. Polarized light microscopic observations revealed that only the caffeine-treated wood induced the formation of transcrystalline structures in the polylactide. Incorporation of the modified filler into the matrix was also responsible for changes in the thermal stability and decreased hydrophilicity of the material. Most importantly, the use of black cherry wood treated with caffeine imparted antifungal properties to the polylactide-based composite, effectively reducing growth of Fusarium oxysporum, Fusarium culmorum, Alternaria alternata, and Trichoderma viride. For the first time, it was reported that treatment of wood with a caffeine compound of natural origin alters the supermolecular structure, nucleating abilities, and imparts antifungal properties of polylactide/wood composites, providing promising insights into the structure-properties relationship of such composites.
Fruit Vinegars as Natural and Bioactive Chitosan Solvents in the Production of Chitosan-Based Films
Natural fruit vinegars, derived from various fruits, enhance culinary experience and offer potential health benefits due to their bioactive compounds. In this study, fruit vinegars (apple, blackcurrant, and cherry) were used as natural solvents for producing chitosan films, introducing an environmentally friendly approach. Fruit vinegars and chitosan-based solutions were examined for their antioxidant and antimicrobial properties. In turn, the obtained chitosan films were characterized by their antimicrobial, mechanical, and structural properties. Both fruit vinegars and film-forming chitosan solutions showed antioxidant activity, and chitosan–cherry vinegar solutions exhibited the highest antiradical and ferrous ion-chelating effect. All solvents and chitosan-based solutions were characterized by antimicrobial properties, especially against Pseudomonas aeruginosa (inhibition zone > 28 mm). Antimicrobial activity was also preserved in the case of chitosan-based film, especially when produced with cherry vinegar, which showed activity against the broadest spectrum of bacteria. The largest zone of inhibition for all samples was observed for P. aeruginosa in the range of 19 mm from the inhibition zone to >28 mm, depending on the type of vinegar used as a solvent. The conducted tests showed that the type of vinegar used also affects the mechanical parameters of the films obtained, such as elongation at break, for which values were recorded from 3.97 to 4.93 MPa, or tensile strength, for which the values were recorded from 48.48 to 70.58 MPa. The results obtained demonstrate that natural fruit vinegars, serving as chitosan solvents, can be an alternative to traditionally used acidic solvents, yielding films with favorable properties.
Activity of Viscum album L. extract against wood-rot fungi and its potential application in wood preservation
Valorization of Forest Biomass Through Pyrolysis: A Study on the Energy Potential of Wood Tars
Forest biomass is a renewable source of environmentally friendly material—wood. However, wood processing generates large amounts of by-products, including branches. These byproducts are often used as firewood; however, they can be used much more effectively. In this study, the pyrolysis of two woods, namely birch and pine, was proposed. The liquid products of pyrolysis were studied by FTIR spectroscopy, and the heating value of these products was evaluated. In order to find the optimal pyrolysis temperature from the point of view of the calorific value of the product, the process was carried out at four temperatures: 450, 500, 550, and 600 °C. The liquid product yielded three fractions, from which two were analyzed, namely the dense tar fraction and light liquid fraction. FTIR analysis results clearly demonstrated that samples from different fractions differ from one another, yet the results within the same fraction are remarkably similar. The tar fraction was characterized with a higher gross calorific value between 42 to 50 MJ/kg, while the liquid fraction gross calorific value was between 29 and 39 MJ/kg; in general, pine wood yielded products with higher calorific values. The pyrolysis of small wood industry by-products is an interesting method of utilization, yielding not only a liquid product with good calorific properties, but also a solid product, namely biochar, which may be used in carbon storage or used as a soil amendment.
The Effect of Salinity on Heavy Metal Tolerance in Two Energy Willow Varieties
This study evaluated the response of two willow varieties, Salix × smithiana Willd. and Salix viminalis L. var. Gigantea, to selected heavy metals and elevated soil salinity, simulating complex environmental conditions during phytoremediation. Plants propagated from stem cuttings were cultivated in pots under field conditions in soil artificially contaminated with a mixture of Cd, Ni, Cu, Zn, and Pb salts at two concentration levels representing lower and higher guideline thresholds. Sodium chloride was added to induce salinity stress. S. × smithiana exhibited enhanced growth under combined metal and salinity stress, suggesting efficient tolerance mechanisms. This was reflected in elevated relative water content (RWC) and increased accumulation of Zn and Cd in shoots. In contrast, Gigantea showed growth inhibition and primarily sequestered metals in roots, indicating a stress-avoidance strategy and reduced metal translocation. While salinity alone negatively affected both varieties, its combination with metals mitigated growth reduction in S. × smithiana, possibly due to improved ion homeostasis or cross-tolerance. Zn and Cd displayed the highest bioconcentration and mobility. Based on bioconcentration factor (BCF) and translocation factor (TF), S. × smithiana appears suitable for phytoextraction, whereas S. viminalis var. Gigantea appears suitable for phytostabilization. These results support species-specific approaches to phytoremediation in multi-contaminant environments.
The effect of urea-formaldehyde adhesive modification with diisocyanate-functionalized nanocellulose on the properties of particleboard
Kombucha as a Solvent for Chitosan Coatings: A New Strategy to Extend Shelf Life of Red Peppers
Plastic pollution and environmental degradation necessitate the development of natural, biodegradable food preservation materials. This study examined chitosan-based film-forming solutions using kombucha derived from black tea, lemon balm, and chamomile as natural solvents rich in bioactive compounds. Lemon balm kombucha solutions were used to create chitosan films and coat red peppers. The study assessed the mechanical properties of the films and the effects of chitosan coating on peppers, including texture, ascorbic acid content, sensory attributes, and antioxidant activity. Microbiological tests showed that a chitosan–lemon balm kombucha solution acted against Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Lemon balm kombucha had high total phenolic (381.67 µg GAeq/mL) and flavonoid (21.05 µg Qeq/mL) contents. The chitosan film exhibited a tensile strength of 11.08 MPa and an elongation at break of 53.45%. The water vapor transmission rate of the obtained chitosan film was 131.84 g/m2·24 h. Coated peppers showed a 32% increase in skin strength and retained 11% more ascorbic acid after 15 days. Sensory evaluation revealed no significant differences from controls. These results highlight lemon balm kombucha as a promising natural solvent for chitosan coatings, which have the potential to extend red pepper shelf life and to support food preservation.
Modified Buckwheat Husk as a Filler for Urea–Formaldehyde Resin in Plywood Production
The aim of the presented research was to determine the suitability of both non-modified and modified buckwheat husk (BH) as a filler for urea–formaldehyde adhesive in plywood production. The effect of two modification methods, acetylation and silanization, was investigated. Infrared spectroscopy outcomes confirmed that both acetylation and silanization of the filler had occurred. Based on the results, it was found that the introduction of BH had a significant effect on both the adhesive properties and the characteristics of the manufactured plywood. The application of non-modified husks led to a reduction in viscosity and an extension of the gelation time, and the produced plywood boards were characterized by reduced bonding quality and increased delamination. Modification of the husk surface by acetylation and silanization with 3-aminopropyltriethoxysilane contributed to the noticeable improvement in the resin properties. On the other hand, the improvement in plywood properties, consisting of the increase in bonding quality and reduced delamination, was observed only in the case of the silanized husk. Furthermore, the use of non-modified and acetylated husk did not significantly influence the formaldehyde emission. The reduction in the investigated emission of formaldehyde was observed only in the case of variants containing 15 and 20% of silanized buckwheat husk.
Coffee silverskin and cocoa pod husk modified with methacrylic acid as fillers for the urea-formaldehyde resin in plywood production
Effect of Antisolvent Used to Regenerate Cellulose Treated with Ionic Liquid on Its Properties
The solvolysis reaction with ionic liquids is one of the most frequently used methods for producing nanometer-sized cellulose. In this study, the nanocellulose was obtained by reacting microcrystalline cellulose with 1-ethyl-3-methylimidazolium acetate (EmimOAc). The aim of this research was to determine the influence of various antisolvents used in the regeneration of cellulose after treatment with ionic liquid on its properties. The following antisolvents were used in this research: acetone, acetonitrile, water, ethanol and a mixture of acetone and water in a 1:1 v/v ratio. The nanocellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM) and elemental analysis (EA). The results show that the antisolvent used to regenerate cellulose after the solvolysis reaction with EmimOAc affects its properties. Water, ethanol and a mixture of acetone and water successfully removed the used ionic liquid from the cellulose structure, while acetone and acetonitrile were unable to completely remove EmimOAc from the cellulosic material. The results of the XRD analysis indicate that there is a correlation between the ionic liquid content in the regenerated cellulose and its degree of crystallinity. Among the tested solvents, water leads to the effective removal of EmimOAc from the cellulose structure, which is additionally characterized by the smallest particle size and non-formation of agglomerates.
Understanding stoichiometric adjustments in a freshwater plant: Responses to sediment and water nutrient dynamics across lake trophic gradients
AbstractDespite ongoing efforts to reduce nutrient inputs, eutrophication continues to disrupt biogeochemical cycles and destabilize freshwater food webs. In this study, we examine the stoichiometric responses of the freshwater plant Myriophyllum spicatum under varied environmental conditions across lakes of differing trophic status. Specimens were collected from lakes with a wide natural range of macro‐ (C, N, P) and micronutrient (Fe, Cu, Zn) concentration in both water and sediments. We applied the ecological stoichiometry framework and analyzed the relationship between nutrient availability (water and sediments) and the elemental composition of M. spicatum's organs (leaves, stems, and roots). The C : N : P ratios in organs were not affected by eutrophication. Instead, all macro‐ and micronutrient concentrations differed between plant organs. N concentration was highest in leaves and roots, indicating uptake from both sources. Furthermore, sediments significantly influenced the plant organs' C, P, and Zn concentration, while nutrients in the water column showed no correlation. Leaves demonstrated flexibility in C and Zn concentrations, negatively correlating with sediment levels of these elements. The concentration of micronutrients was highest in the roots. Our results indicate distinct nutrient allocation strategies for different plant organs: leaves are rich in N to support photosynthesis, stems store C and P, aiding growth and reproduction, and roots accumulate micronutrients Fe, Zn, and Cu. It highlights sediments as a critical nutrient source for M. spicatum, shaping its elemental composition. The relationship between organisms' biochemistry, trophic interactions, and their transformation into dead organic matter is crucial for understanding environmental stress impacts on aquatic ecosystems.
Chitosan-Based Films with Essential Oil Components for Food Packaging
Chitosan-based films show great potential in terms of application in food preservation and are also promising carriers of biologically active ingredients. This paper presents the potential use of chitosan-based films with the addition of essential oil components, e.g., carvacrol, eugenol, and isoeugenol, intended for food packaging. The characteristics of the obtained films were determined, including antibacterial, mechanical, barrier, and structural parameters. In addition, the antibacterial and antioxidant effects of the essential oil components were assessed. Eugenol (44.41%) and isoeugenol (43.56%) showed high antiradical activities, similar to the activity of Trolox (44.33%), which is used as a standard antioxidant. In turn, carvacrol was characterized by the strongest effect against the examined strains of bacteria, both Gram-positive and Gram-negative. The chitosan film with carvacrol showed the most valuable antibacterial and mechanical properties (tensile strength and elongation at break). The antibacterial activities of the chitosan–carvacrol films were higher than that of the carvacrol solution. The inhibition zones of the chitosan–carvacrol films were in the range 29–41 mm (except for Enterococcus faecalis, with an inhibition zone of 15 mm) compared to the inhibition zones of the carvacrol solution (28 mm). The results showed that chitosan is an effective carrier of fragrance compounds, mainly carvacrol. However, all the tested chitosan-based films with the addition of fragrance compounds showed appropriate parameters (biological, mechanical, and barrier), which makes them an ecological alternative to plastics intended for food packaging.