8639 research outputs found
Sort by
Low-energy alkaline hydrogen peroxide pretreatment for high-value application of corn stalk
No full textTo address the Sustainable Development Goals proposed by the United Nations, especially the ones including energy, environmental, and climate targets, switching from fossil-based refinery to biorefinery is needed. This transition includes the use of different bioresources that are rich in lignocellulose content. To maximise the value of these resources, each fraction should be separated in a close-to-native state, avoiding structural disruption or degradation. Some of the first biorefinery concepts were based on obtaining preserved cellulose fraction while neglecting lignin potential. Recently, lignin-first biorefinery approaches have emerged, providing an opportunity to utilise lignin as a building block for high-value applications. Different types of pretreatments were developed for lignocellulose fractionation, namely mechanical, chemical, thermal, and biological.
Among chemical pretreatments, alkaline reagents proved to be the best choice for efficient lignin and hemicellulose removal while preserving cellulose fraction. Besides increasing the enzymatic digestibility of the cellulose fraction, lignin produced using alkaline pretreatment has a low molecular weight and is, therefore, more suitable for high-value valorisation (Madadi et al., 2022).
Among alkaline reagents, sodium hydroxide is mostly employed due to the lower price, higher solubility and alkalinity, and better degrading performance. However, when using sodium hydroxide, black liquor is generated, lowering the value of the obtained lignin fraction, which is on technical grade (Zahoor et al., 2023). This could be avoided by implementing alkaline hydrogen peroxide, which can remove lignin effectively under milder conditions due to its ability to attack carbonyl and ethylene groups selectively (Ho et al., 2019). Still, elevated temperatures are needed to attack the phenolic ring rather than just the aliphatic part of lignin. Under these conditions, obtained lignin is often condensed due to the formation of C-C bonds, and thus, its high-value valorisation is limited. To prevent lignin condensation and reduce prolonged heating of samples, this study combined cold plasma with 10-minute-long hydrogen peroxide alkaline pretreatment at 70°C. Cold plasma (CP) was implemented due to its ability to cleave C-C bonds (Cao et al., 2020) while simultaneously generating new portions of H2O2, making this pretreatment more efficient. One set of samples was solely subjected to hydrogen peroxide alkaline pretreatment to assess the contribution of CP. Corn stalk was selected as a model substrate due to its abundance, which is derived from corn being the most cultivated crop worldwide.
Upon the corn stalk pretreatment, cellulose-, hemicellulose- and lignin-rich fractions were isolated. The lignin-rich fraction obtained with CP-assisted pretreatment showed improved total phenolic content (140 μg GAE/mg lignin) compared to the one obtained after alkaline pretreatment (107 μg GAE/mg lignin). Additionally, SEM micrographs confirmed that lignin particles of micro- and nanoscale were produced. These particles became more uniformly shaped and independent when CP was implemented (Fig. 1). Moreover, the obtained lignin-rich fraction was bright in colour (Fig. 1), unlike technical lignins, whose dark colour is one of the main obstacles for further high-value application. After CP-assisted pretreatment, the cellulose-rich fraction comprised 86% less lignin than raw biomass. The high delignification rate made the cellulose-rich fraction susceptible to enzymatic degradation, leading to an approximately 3.5 times higher conversion rate than the raw biomass. Significant results were also achieved after anaerobic digestion, with cellulose-rich fraction obtained with CP-assisted pretreatment producing around 94% of the biomethane yield obtained when pure cellulose was used as a substrate.
These results showed that the cellulose, hemicellulose and lignin fractions could be successfully separated under milder pretreatment conditions. Obtained lignin-rich fraction could be furtherly tested for application as UV filter in cosmetic formulations or implemented in agriculture as a nano-carrier of nutrients (Jeffri et al., 2024). The cellulose-rich fraction proved to be suitable for producing platform chemicals and/or biogas. However, the proposed pretreatment could be optimised towards achieving fractions of higher purity and with an improved recovery rate
Microbubble Plasma-Enhanced Oxidative Pretreatment for Improved Biogas Yield from Marginal Biomass
No full textIntroduction: Lignocellulosic biomass is a renewable resource that is abundantly available for producing sustainable energy. However, its complex matrix, particularly due to the recalcitrant lignin component, limits biogas yield in anaerobic digestion (AD) processes. Despite the development of numerous pretreatment strategies, there is still a requirement for sustainable, scalable, technically feasible, and industrially applicable technologies that can effectively degrade lignin and improve the accessibility of substrates to microbes. This study investigates the integration of the Fenton process with a microbubble plasma technology as a novel oxidative pretreatment strategy to enhance lignin degradation in whole maize and improve biogas production through AD. Experimental: The pretreatment was performed by introducing maize into a Fenton reagent (a mixture of hydrogen peroxide and iron salts) within the microbubble plasma reactor, which operated under atmospheric pressure. The Fenton solution initiates hydroxyl radical formation, while the plasma enhances the effect by producing more reactive oxygen and nitrogen species, including hydroxyl radicals, ozone, peroxynitrites, and nitric acid. This combination creates a synergistic oxidative environment, facilitating lignin breakdown. Varying Fenton solution molar ratios of hydrogen peroxide to iron salts from 1:10 to 1:75 and treatment durations of 30 min to 90 min were investigated. To evaluate structural and chemical modifications to lignocellulosic biomass, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to characterise both treated and untreated samples. The National Renewable Energy Laboratory (NREL) standard protocol was implemented to ascertain the lignin content of biomass samples. The biomethane yield is evaluated through batch tests of the Biochemical Methane Potential (BMP) using the AMPTS II system. Concurrently, a continuous stirred anaerobic digestion system has been studied to assess the performance of the process under semi-continuous conditions. Key findings: The FTIR results demonstrate a notable decrease in the intensity of peaks associated with lignin linkages, suggesting that the plasma-assisted Fenton oxidation effectively contributed to the disruption of lignin structure. Increased surface disruption and porosity are evident in pretreated maize as evidenced by SEM images. The pretreated samples exhibited a significant improvement in methane production, as indicated by the batch Biochemical Methane Potential test results. Furthermore, the liquid fraction collected post-treatment was analysed for solubilised lignin and hemicellulose, which may hold potential for resource recovery or biorefinery integration
Embryo sac functionality in autochthonous cherry genotypes grown in the Balkan region
No full textThe present study investigated the functionality of embryo sacs in two contexts: (i) field conditions with two pollination treatments (open and cross) to observe potential differences in development and (ii) high constant temperatures within the climate change framework to examine their impact. Embryo sac functionality was evaluated in four autochthonous sweet and sour cherry genotypes over two years. In the field, flowers were collected at five-time points starting from anthesis, then embedded in paraffin, sectioned, and stained. In contrast, three-time points were utilized to assess the effects of constant temperature. The resulting histological sections were observed under a microscope. The later-flowering sweet cherry genotypes at anthesis displayed more advanced embryo sac stages. The stages of embryo sacs in sour cherry genotypes showed no consistent pattern concerning flowering time. A higher percentage of early and later stages of embryos with cellular endosperm were observed across all cherry genotypes in open compared to cross-pollination. Under constant temperatures, late-flowering sweet cherry genotypes experienced a rapid decline in embryo sac viability at both temperatures. However, this trend was not noted in sour cherry genotypes. Our histological data from autochthonous sweet and sour cherry genotypes and other pomological studies will support future breeding efforts with these genotypes
Engineering Ru@Ir Core–Shell Nanoparticles on Titanium Oxynitride–Graphene Support for a Highly Active and Durable pH-Universal Hydrogen Evolution Reaction
No full textThe rational design of electrocatalysts with high activity, durability, and low precious metal content is key to advancing hydrogen production via water electrolysis. Here, we present a multifunctional electrocatalyst based on Ru@Ir core–shell nanoparticles anchored on a conductive titanium oxynitride–graphene hybrid support (Ru@Ir/TiOxNy-C), achieving superior performance for the hydrogen evolution reaction (HER) in both acidic and alkaline media. The combination of the core–shell Ru@Ir architecture and the strong metal–support interaction (MSI) with TiOxNy optimizes hydrogen and hydroxide adsorption energies, as confirmed by X-ray photoelectron spectroscopy and density functional theory (DFT) calculations. In alkaline media, Ru@Ir/TiOxNy-C outperforms commercial Pt/C with a remarkably low overpotential of 13 mV at 10 mA cm–2 and high mass activity, while in acidic conditions, it rivals Pt/C and surpasses monometallic analogs. The long-term stability of the composite is attributed to the enhanced nanoparticle anchoring and structural integrity provided by the TiOxNy support. This work shows that combining core–shell nanostructures with engineered conductive supports can effectively replace platinum in HER applications. Such a nanocomposite strategy offers a versatile platform for the development of advanced electrocatalysts across a broad range of energy conversion reactions
Development of Nano ZnO-Embedded Gelatin/Alginate Bioscaffolds for Potential Skin Tissue Regeneration via Oxidative Stress Modulation and ECM Mimicry
No full textEngineering of biomaterials for advanced skin tissue regeneration requires optimization of critical parameters including inter-connected porous structure, biomaterial stability, hydrophilicity, biocompatibility, and bioactivity. These features enable themimicry of the skin tissue microenvironment and support the key phases of the regeneration process, which are crucial for ef-fective tissue repair. Another important requirement for successful skin tissue regeneration is the modulation of oxidative stress,as excessive accumulation of reactive oxygen species (ROS) at the site of the skin lesion can hinder healing and cause chronicinflammation and scarring. To address these challenges, we propose a reductionist therapeutic approach to skin tissue regenera-tion by developing bio-sourced scaffolds that replicate the native extracellular matrix (ECM), neutralize ROS levels, and activelypromote tissue regeneration at both structural and molecular levels. These nano ZnO-embedded gelatin/alginate bioscaffoldswere prepared via a simple crosslinking reaction and loaded with carefully selected active agents with antioxidant and skintissue regenerative potential. Characterization studies of the bioscaffolds confirmed their porous interconnected morphologywith tunable porosity (92%–94%), mechanical strength (1.95–3.22 MPa), hydrophilicity, stable adhesion to skin tissue, and ROS-scavenging activity. Additionally, the bioscaffolds demonstrated simultaneous release of quercetin, allantoin, and caffeic acid,and both biocompatibility—in vitro on human fibroblasts (MRC5) and in vivo on Caenorhabditis elegans. Overall, these findingsprovide valuable insight into the design of multifunctional bioscaffolds as a promising therapeutic platform for skin tissue regen-eration application, which simultaneously modulates oxidative stress, replicates ECM architecture, and stimulates the healingcascade, ultimately enhancing skin tissue repair and reducing scarring
Cavitation erosion parameters of laser sintered MS1 steel tested according to ASTM G32 standard
No full textThe paper analyses data obtained from cavitation erosion testing of MS1 tool steel. The testing
samples, cylindrical in shape with a height of 5 mm and a diameter of 10 mm, were fabricated using Direct Metal Laser Sintering (DMLS), a 3D printing technique. The samples were subjected to cavitation erosion testing in accordance with the ASTM G32 standard for a total duration of 4 hours. Mass loss measurements were recorded every 30 minutes. Based on the collected data, key parameters such as Cumulative Mass Loss, Cumulative Volume Loss, Mean Depth of Cavitation Erosion (MDE), and Mean Depth Erosion Rate (MDER) were determined and analyzed. Understanding material behaviour under cavitation conditions is crucial for its potential application in manufacturing mechanical components, particularly gears, bearings, and valves, where cavitation-induced damage is a common issue in operational environments. Given that the specimens were produced by metal powder-based 3D printing, it is especially relevant to assess the performance of such material under these conditions. This insight is particularly valuable for the geometric optimization of components to minimize erosion, where additive manufacturing offers significant advantages over conventional production technologies
Towards bio-inspired wound dressings: Lactobacilli targeting Gram-negative pathogens
No full textDiabetes mellitus includes a group of chronic metabolic disorders characterized by elevated
blood glucose level or hyperglycemia. Among its most severe complications is the development
of diabetic foot ulcers (DFUs), “hard-to-heal“ wounds that are highly susceptible to infection
which may lead to amputation, sepsis, or even death. The efficacy of conventional treatments,
including systemic antibiotics and topical antimicrobials, is increasingly compromised by the
rise of multidrug-resistant pathogens. Consequently, there is an urgent need for innovative and
multi-targeted therapeutic strategies. In this context, probiotics have gained attention due to
their intrinsic antimicrobial, anti-inflammatory, and immunomodulatory properties. The aim of
this study was to develop and evaluate biocomposites composed of probiotic bacteria
immobilized onto pads made of activated charcoal fabric. Initially, suitable probiotic strains
were selected based on their inhibitory actiivity against a resistant Pseudomonas aeruginosa and
Klebsiella pneumoniae isolated from patients wounds. All experiments were conducted under
conditions mimicking the DFU microenvironment, using simulated wound fluid under
microaerophilic and hyperglycemic conditions. Subsequently, the immobilization method was
optimized to ensure the viability and long-term stability of selected strains on the pads.
Imobilized probiotic cells were visualized using electron microscopy and their viability was
assessed in normal saline solution (0.9 % w/v NaCl). Further experiments will evaluate the
antimicrobial activity of these biocomposites against clinically relevant pathogens associated
with chronic wounds, under conditions mimicking the hyperglycaemic wound environment
Examination of the Content of Ionic Species in Pectin Fruit Products Using the Ion Chromatography Method
No full textObjective:
In this work, the content of ionic species in commercial pectin products from fruit: jams, marmalades and dietary jam sweetened with fructose from the market of the Republic of Serbia was examined, using the method of ion chromatography. The pH value of these products and total acidity were also tested. Fruit, which is the main ingredient of these products, contains the necessary macro and micro elements, vitamins and other biologically valuable substances, which are very important for the proper functioning of the human body. The elements such as Na, Mg, P, S, Cl, K and Ca are considered essential nutrients and are necessary in amounts in mg/kg per day.
Methods:
Ion chromatography (IC), as a modern technique for the separation and quantitative determination of ions in solution, provides the possibility of simultaneous determination of several ions in a short period of time, good reproducibility of results and the possibility of using different detectors. Due to its favourable characteristics in terms of high sensitivity, good selectivity and high precision, IC is widely used as a method for the analysis of all inorganic ions. The pH value and total acidity were determined by the potentiometric method.
Results:
The amounts of ionic species range within the limits that cannot endanger human health, and together with other foods, the prescribed minimum doses of these elements are provided for the proper functioning of the body.
In the examined jams and marmalades, potassium is the most abundant element. Cation K+ is present in amounts of 30-62.5 mg per 100 g of product, followed by Ca2+ (3.0-6.75 mg/100 g), Na+ (1.45-3.25 mg/100 g), while Mg2+ is below the detection limit in all samples (< 0.125 mg/100 g). The content of cations K+, Ca2+ and Na+ and especially magnesium in jams and marmalades is lower than the average content of the mentioned elements in the fresh fruit from which they are produced. The reason for this may be that part of certain elements was not present in the extract that was analyzed because it was in the form of water-insoluble salts, therefore, alternative methods of sample preparation should be considered for the determination of these cations in such a complex matrix. Potassium is most abundant in dietary apricot jam, followed by plum jam, while calcium and sodium are most abundant in mixed fruit marmalade. During the analysis of cationic species in jams and marmalades, no major variations were recorded, in contrast to anions, where the values vary in a wider range. The most abundant anion in the examined products is SO42− (14-87.5 mg/100 g), followed by Cl− (3.25-42.5 mg/100 g), NO3− (2.2-9.25 mg/100 g), PO43− (< 0.25 mg/100 g). The pH value in jams and marmalades varies in the range from 3.29 to 3.85. The highest value (pH 3.85) in extra apricot jam, while the lowest in mixed fruit marmalade (pH 3.29). The total acidity of the tested jams and marmalades is in the range from 0.53% to 1.71% calculated as citric acid, with the lowest percentage in rosehip marmalade and the highest in dietary apricot jam.
Conclusions:
The determination of minerals in food products is important because of their role in the human body. The intake of sufficient amounts of mineral materials is necessary for the proper performance of many functions in the human body. These elements participate in the construction of bones and soft tissues, heart function, regulation of osmotic pressure, protein biosynthesis, transport through the cell membrane, they activate many enzymes, etc.
In order to determine the correlation between ionic speciation and pH, i.e. the distribution of ionic species depending on the acidity of the solution, as well as the relationship between cationic and anionic species, Pearson correlation analysis was performed, as well as the principal component analysis (PCA)
Microwave-assisted extraction of bromadiolone from paraffin blocks: A rapid and efficient sample preparation approach
No full textObjective
The study aimed to develop and evaluate a microwave-assisted extraction method for the determination
of bromadiolone in complex paraffin-based rodenticide formulations. The method sought to address the
limitations of traditional manual extraction [1], including its time-consuming nature, procedural
complexity, and excessive solvent usage
Valorizacija sojine sačme za proizvodnju visokoproteinske stočne hrane i proizvoda sa dodatom vrednošću korišćenjem novog soja Aureobasidium pullulans
No full textSoybean meal (SBM) is a by-product of soybean oil production. It is a high-quality protein supplement for animal feed. However, it is rich in anti-nutritive factors and indigestible components, among which the special attention is focused on galacto-oligosaccharides, due to the lack of α-galactosidase in monogastric animals. The main goal of this study was to apply fermentation using a selected strain of black yeast-like fungus of the SBM to obtain a high-protein, low-oligosaccharide soy-based product. Screening for an appropriate strain of Aureobasidium spp. among natural isolates from grapes has been performed. The highest α-galactosidase activity of 0.89 U cm-3 was produced by the strain identified as A. pullulans P8. It was applied in SBM submerged (SmF) and solid-state fermentations (SSF). Maximal crude protein yield (61 % based on dry weight) and the lowest galacto-oligosaccharides content were obtained after 3 days of SmF at 30 °C and 10 % of dry matter. SSF produced 58 % crude protein after 7 days of incubation at 30 °C with substrate containing 30 % of dry matter. Extracellular enzymatic activities of cellulase, pectinase, amylase, xylanase, and α-galactosidase were detected in the supernatant after SmF, indicating its potential for hydrolysis of various lignocellulosic biomass substrates.Sojina sačma je nusproizvod koji nastaje nakon ekstrakcije ulja iz zrna soje. S obzirom na to da je bogata visokokvalitetnim proteinima, sojina sačma se koristi kao dodatak za stočnu hranu. Međutim, bogata je takođe i antinutritivnim faktorima i nesvarljivim komponentama, među kojima je posebna pažnja usmerena na galaktooligosaharide, zbog nedostatka α-galaktozidaze kod monogastričnih životinja. Osnovni cilj ovog istraživanja bio je da se odabere pogodan soj crne gljivice nalik kvascu (Aureobasidium spp.) među deset prirodnih izolata iz grožđa, koji bi tokom fermentacije sojine sačme dao proizvod sa velikim sadržajem proteina i malim sadržajem oligosaharida. Sa tim ciljem odabran je izolat P8 koji je pokazao najveću aktivnost α-galaktozidaze od 0,89 U cm-3. Odabrani soj je identifikovan kao A. pul-lulans P8. Maksimalni prinos sirovih proteina u fermentisanoj sojinoj sačmi (61 % računato na suvu materiju) i najmanji sadržaj galaktooligosaharida dobijeni su nakon 3 dana inkubacije na 30 °C potopnom fermentacijom pri sadržaju 10 % suve materije sojine sačme. Fermen-tacijom na čvrstom supstratu dobijeno je 58 % sirovih proteina nakon 7 dana inkubacije na 30 °C pri sadržaju suve materije od 30 %. U supernatantu dobijenom nakon potopne fermen-tacije izmerene su aktivnosti ekstracelularnih enzima (celulaze, pektinaze, amilaze, ksilanaze i α-galaktozidaze), što ukazuje na potencijal ovog pomoćnog proizvoda za hidrolizu različitih lignoceluloznih supstrata