This study aimed to evaluate the potential of branches of black chokeberry, sea buckthorn, and black currant as raw materials for the development of pharmacologically active compounds, primarily oligomeric proanthocyanidins (OPCs), as they exhibit a broad spectrum of biological activities, including antioxidant, antimicrobial, anti-inflammatory, anticancer, etc. Branch biomass collected in spring and autumn of 2023-2025 was analyzed for its functional group profile and used for the isolation of OPCs with ethanol, an ethanol-water mixture (1:1, v/v), and an ethanol-acetone-water mixture (4:1:5, v/v/v). The highest yield of OPCs (up to 14% of DB) was achieved using the ethanol-acetone-water solvent mixture. Using LC-MS/MS, the OPC composition was analyzed and found to consist of dimers (m/z 577), trimers (m/z 865), and tetramers (m/z 1153). The maximum OPC content was observed in autumn samples. Mechanical pretreatment enhanced OPC accessibility by disrupting cell walls and increasing particle surface, facilitating release from the matrix and yielding up to 1.2-fold more OPCs than from untreated biomass. Quantification of 22 elements in the biomass by ICP-MS revealed low levels of toxic metals along with the presence of nutritionally relevant elements. Therefore, from a chemical safety perspective, biomass can be considered suitable for use as a source of OPCs.

Bacteria and viruses’ potential collaboration has been reported to result in enhanced infection pathogenesis. New antimicrobial agents are necessary, but stronger synthetic antibiotics cause more severe side effects. The relevance of natural agents has increased in the post-COVID-19 period also due to COVID-induced cytokine storm, causing severe complications. This study aimed to evaluate Aronia melanocarpa branches for producing anti-SARS-CoV-2, anti-inflammatory, and antimicrobial preparations, and their synergistic activity with antibiotics. Biomass water and water-ethanol extracts were analyzed for total polyphenols, tannins, individual compounds (UHPLC-MS/MS), content of functional OH groups. Anti-SARS-CoV-2 activity was tested using SARS-CoV-2 (2019-nCoV) Inhibitor Screening ELISA Kit, anti-inflammatory activity - in peripheral blood mononuclear cells (PBMNC) under normal and inflammatory conditions; antimicrobial and synergistic efficacy with antibiotics were tested against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Oligomeric proanthocyanidins were dominant compounds in the extracts, with the highest concentration in autumn samples (35% per dry extract). The extracts and oligomeric proanthocyanidins were effective in inhibiting the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein and regulating inflammatory processes caused by viral and bacterial infections, including the reduction of IL-6 and regulation of IL-10 secretion. Proanthocyanidins and extracts exhibited significant anti-biofilm activities and showed synergistic activity with antibiotics.

Fruit shrubs' lignocellulosic biomass remaining as waste after harvesting and/or after pruning is an underutilized, little-explored bioresource. Sea buckthorn (Hippophae rhamnoides L.), aronia (Aronia melanocarpa) and blackcurrant (Ribes nigrum) berries are rich in biologically active compounds, so these shrubs' woody biomass derivatives are prospective investigation objects. The influence of pre-treated biomass, extracts, and purified proanthocyanidins on the oxidative stability of lipid-based systems was studied by accelerated oxidation method. Emulsion stability, antimicrobial activity against bacteria that causes acne-Cutibacterium acnes; contaminating wounds; skin care products-Streptococcus pyogenes, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus; cytotoxicity and phototoxicity of extracts and proanthocyanidins on HaCaT human keratinocytes were tested. The study established that biomass, lipophilic extracts obtained using liquefied hydrofluorocarbon, and hydrophilic extracts obtained by aqueous ethanol increased oxidative stability of lipid-based formulations. Compounds with skin-protecting properties were detected. Sea buckthorn and aronia hydrophilic extracts and proanthocyanidins had the highest antimicrobial activity. Low phototoxicity was revealed, emphasizing safety and applicability in topical formulations; human HaCaT keratinocyte viability was the best with aronia extracts, but none of the other samples decreased cell viability by more than 50%. It was proven that agro-waste biomass is a prospective source of multifunctional ingredients for cosmetic and pharmaceutical topical formulations.

The aim of research was to evaluate the impact of low rates of application of environmentally friendly organo-mineral soil amendments on yields components (number of productive tillers m2, 1000 grain weight, grain number per ear), grain yield and yield quality of spring and winter wheat under organic farming conditions. Soil amendments were obtained based of forest logging residues - lignocellulosic biomass, after isolation of polyphenols by water extraction and enrichment with silicon (Si), included the content of polyphenolic compounds. The soil amendments were used for seed material treatment. Field experiments were carried out in the certified organic farming field. The control variant and organo-mineral soil amendments, containing inorganic oligomer in various mass ratios (three variants) were tested. The varieties (spring wheat ‘Robijs’, winter wheat ‘Edvins’), certified for growing under organic farming conditions, were used in trial. It was shown that the treatment of seed material with organo-mineral soil amendments increased the number of productive tillers as well as have a beneficial effect on the yield (the increase till 21.6% compared to the control) but decreased the number of grains per ear of spring wheat, depending on concentration of inorganic oligomers). In variant with the highest tested concentration of inorganic oligomer, a trend towards yield growth for winter wheat can be observed. The obtained results show that the treatment of seed material with promotes plant growth and development, researches should be continued.

Blackcurrant (Ribes Nigrum L.) is one of the most common shrubs in Latvia, in addition to fruits and leaves, twigs cut in spring and autumn are rich in oligomeric polyphenols - proanthocyanidins, which have powerful antioxidant, antimicrobial, anti-inflammatory properties. The yield of proanthocyanidin-containing extracts ranged from 12 to 22%/DM. At the same time, the twigs cut in autumn were richer in proanthocyanidin than in spring. The strong antimicrobial properties of the extracts showed their effectiveness against a wide range of bacteria, which makes the extracts promising for use in medicine and the food industry. All extracts introduced into the lipid-based cosmetic cream showed antioxidant activity comparable to reference samples. This indicates the potential for using these extracts as active ingredients in cosmetics aimed at protecting the skin from the negative effects of free radicals. The results obtained open up new opportunities for developing innovative cosmetic formulations with improved antioxidant properties that help slow down the ageing process of the skin and maintain its health. The use of blackcurrant twigs is a sustainable and cost-effective source of valuable bioactive compounds.

The manuscript explores the valorization of forest logging residues, collected during forest management operations between summer 2023 and spring 2025 in mixed deciduous and coniferous forests, as a raw material for producing valuable bioactive products. These products offer a sustainable alternative to synthetic pesticides and fertilizers. Seven batches of biomass, comprising understory trees and branches from deciduous (mainly aspen, birch, and grey alder) and coniferous (mainly Scots pine) species, were collected during different seasons, crushed, and extracted using an ethanol-water solution. The yield of hydrophilic extracts containing proanthocyanidins (PACs) ranged from 18 to 25% per dry biomass. The highest PACs concentration (42% of extract dry mass) was found in small branches with a high bark content. The extracts and PACs at concentrations of 6.25-12.50 mg mL-1 showed fungicidal activity against several pathogenic fungi, including Botrytis cinerea Pers., Mycosphaerella sp. Johanson, Heterobasidion annosum (Fr.) Bref., and Heterobasidion parviporum Niemel & auml; & Korhonen. Residual biomass after extraction, enriched with sea buckthorn berry pomace and a siliceous complex, was characterized and evaluated for its impact on the growth of Scots pine seedlings and selected agricultural crops. Results from forest and agricultural field trials in 2023-2025 confirmed a positive effect of the fertilizer on crop yield and quality at a low application rate (40 kg ha-1 per crop). Fertilizer increased the yield of radish, dill, potatoes, and wheat by up to 44% (highest for potatoes and dill) compared to the reference, confirming its agronomic value.

Sea buckthorn (Hippophae rhamnoides L.) twigs, remaining after harvesting and pruning, are an underutilized and little-explored biomass resource. This study investigated the content of serotonin in 10 sea buckthorn cultivars (‘Maria Bruvele’, ‘Botanicheskaya Lubitelskaya’, ‘Tatiana’, ‘Otto’, ‘Leikora’, ‘Duet’, ‘Clara’, ‘Lord’, ‘Eva’, ‘Tarmo’) for the first time, and for further adjustment of the extraction conditions, cultivar ‘Maria Bruvele’ was extracted by water and water/ethanol solution with 20-25, 50, 70, and 96% ethanol at different temperatures. The results showed that 50% water/ethanol solutions are the most suitable for extraction, which makes it possible to increase the yield of serotonin. The 2-year-old twigs and bark from ‘Maria Bruvele’ collected in autumn contained higher serotonin content compared to spring-collected biomass. Serotonin sequential purification allowed the serotonin content in the fraction to increase to 26%/DM. The serotonin-rich fraction showed antimicrobial activity against gram-positive and gram-negative bacteria. In tests with salivary amylase, a serotonin-rich fraction at the amount of 0.1-0.4 mg/mL of saliva, under normal physiological conditions, tended to increase amylase activity, resulting in acceleration of starch degradation to glucose. Thus, the results support further study of the serotonin fraction for the treatment of people having underweight, malnutrition, and malabsorption conditions.

Aronia melanocarpa is a hardy berry-producing shrub that demands low maintenance and can grow on almost any type of soil. Since the best fruits can be obtained on the branches younger than 7 years, pruning of 1/3 of the shrub is usually performed each winter or after flowering, and also to remove damaged or overgrown branches. For sustainable production of Aronia melanocarpa berries, it is necessary to find a rational use for this pruning lignocellulosic biomass. Some studies available for Aronia melanocarpa berries show that they are very rich in various biologically active substances with proven functional and pharmacological activities including anti-inflammatory, antioxidant, and antimicrobial properties. The chemical composition of Aronia melanocarpa branches is currently almost unknown. The study aimed to evaluate the composition and potential of chokeberry branches as a source of polyphenols. General chemical characterization of the biomass was carried out using the method of analytical pyrolysis. Extraction of branch biomass was carried out using aqueous alcohol solutions. Quantitative analysis of the extracts showed a large amount of oligomeric proanthocyanidins. The most suitable extractant was determined to obtain the highest yield of the dominant polyphenols in the hydrophilic extract. The antioxidant activity of the hydrophilic extracts as well as antibacterial activity against six pathogenic bacteria was evaluated. The results showed the high potential of chokeberry lignocellulosic biomass as a source of valuable biologically active compounds for the creation of preparations for the healthcare, nutrition industry, and cosmetics.

The purpose of this work was to evaluate the impact of low rates of application of environmentally friendly organo-mineral soil amendments on grown under organic farming conditions dill’s green mass yield and it’s composition, including the content of polyphenolic compounds. Soil amendments were obtained based on forest logging residues – lignocellulosic biomass, after isolation of polyphenols by water-ethanol extraction and enrichment with silicon (Si)-containing inorganic oligomer in various mass ratios. Lignocellulosic biomass is rich in polyphenols which can damage the functionality of the bacterial cell membranes thus inhibiting the growth of soil microorganisms. Polyphenols can be isolated from the lignocellulosic substrate and evaluated in further studies for their potential to protect plants from pathogenic microorganisms. The influence of the prepared soil amendments on soil microorganisms was tested. Field experiments were carried out in a certified biological field intended for scientific purposes. It was shown that soil amendments have a beneficial effect on the yield (42%) and a slight influence on the composition of dill at low amendment application rates. The addition of soil amendments also contributed to insignificant changes in the amount of polyphenols. The soil amendments didn’t influence the soil microorganisms under study. The results confirmed the ability of the soil amendments based on the forest logging residues to activate dill growth.

To obtain a good harvest, regular pruning of fruit trees and bushes is necessary, which results in the accumulation of piles of cut twigs. These twigs are underutilized and form a large number of agricultural waste. Finding a use for this lignocellulosic biomass is necessary for the sustainable use of resources, as well as for creating additional income for berry growers and rural workers. The purpose of the research was to evaluate the potential of branches of various fruit trees and shrubs as a source of valuable oligomeric polyphenolic compounds – proanthocyanidins, which have a wide range of biologically active properties, including antioxidant, antibacterial, anti-inflammatory, anticancer, etc. Hydrophilic extracts of twigs of sea buckthorn (Hippopae rhamnoides L.), black chokeberry (Aronia melanocarpa), black currant (Ribes nigrum L.), red currant (Ribes rubrum), gooseberry (Grossulariaceae), quince (Cydonia oblonga), raspberry (Rubus L.), and grape (Vitis vinifera) were studied for the first time. The main process for isolating proanthocyanidins from the twigs is the extraction by ethanol-water solutions. The amount of extractive substances in the branches containing proanthocyanidins varied from 6 to 28% per DM. The highest content of proanthocyanidins was found in black chokeberry, quince, and sea buckthorn. The proanthocyanidins isolation from hydrophilic extracts was carried out by Sephadex LH-20. The antimicrobial activity of dominant hydrophilic extracts and purified oligomeric proanthocyanidins was studied against eleven pathogenic bacteria and fungus: Pseudomonas syringae pv. syringae, Erwinia rhapontici, Fusarium culmorum, Verticillium dahlia, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus, Candida albicans and Cutibacterium acnes. The MIC and MBC/MFC of extracts ranged from 2 to 6 mg/mL. The antimicrobial activity of purified proanthocyanidins was 10 times higher than that of the extracts.

It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs’ functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar ‘Maria Bruvele’ in the concentration range 0.0313–4.0 mg/mL, no toxic effect was observed.

The aim of this work was to evaluate the effect of low rates (20-40 kg ha-1) of siliconcontaining organo-mineral complex (LignoCel-Si) application on potatoes "Imanta" and summer wheat �Vinjet� productivity and quality, under conditions of organic farming. The LignoCel-Si organo-mineral complex was obtained on the basis of the residues of hydrolysis lignin and sea buckthorn (Hippophae rhamnoides L.) agro-waste lignocellulosic biomass after water-ethanol extraction, and enriched with silicon (Si)- containing inorganic oligomer. The field experiments were carried out at a certified biological field intended for scientific purposes. It was shown that LignoCel-Si has a favorable influence on the harvest volume and product quality at low application rates of 20-40 kg ha-1. In comparison with the control, the additional yield of wheat achieved on the background of LignoCel-Si (20 and 40 kg ha-1) was from 10 to 27 %, and for potatoes from 8 to 21%, correspondingly. The application of 40 kg ha-1 of LignoCel-Si complex also contributed to an increase in the quality of potatoes, which was reflected as an increase in the yield of ware potatoes (potato tubers > 75 mm in diameter). The results confirm the value of the LignoCel-Si complex as a soil biologically active additive and the possibility of its application in biological agriculture.

The comparative analysis of the chemical composition and biological activity of extracts and proanthocyanidins (PACs) isolated from harvesting and pruning agro-waste of fruit shrub-trees (Hippophae rhamnoides L. and Aronia melanocarpa) and forest cleaning waste of non-fruit trees and shrubs (Alnus incana L., Alnus glutinosa and Salix caprea) of Northern Europe was carried out. Aronia melanocarpa and Hippophae rhamnoides L. biomass had the highest proanthocyanidins content (up to 12%) on dry biomass. Fruit trees-derived purified PACs which contained structures with higher polymerization degree had slightly higher antioxidant activity. Both fruit and non-fruit trees PACs can be successfully used in antimicrobial preparations and as antioxidants, and could be interchangeable in the compositions of the antimicrobial preparations, especially against E. coli, P. aeruginosa and S. aureus. Salix caprea, which contained wider range of gallocatechin subunits, and Alnus spp., which contained diarylheptanoids, had shown better anti-microbial activity against B. cereus. Non-fruit trees PACs are desirable in the preparations against C. albicans. PACs from Hippophae rhamnoides L. and Aronia melanocarpa inhibited biofilm formation to 50%, but the extract from Hippophae rhamnoides L. showed the most significant MRSA biofilm growth inhibition (onto 80%). Preparations on the basis of waste biomass-derived compounds will contribute to sustainable pharmacy since their application will allow to diminish the use of antibiotics and to have less toxic side effects both for humans and the environment.

The industrial harvesting of sea buckthorn (SBT) berries with twigs and subsequent pruning creates a large volume of lignocellulosic agro-waste. This study aimed to valorize this agro-waste as a raw material for animal feed and fuel granules, for developing a sustainable cascading SBT production scheme. Five SBT cultivars’ biomasses were characterized by analytical pyrolysis, mass spectrometry, and GC analysis. Condensed tannins, which are undesirable components for animal feed, were separated by extraction. The residue was analyzed for total protein, vitamins (A, C, and E), ash, crude fat, wood fiber, and macroelements (P, K, Ca, and Na), and showed great potential. The heavy metal (Cd, Hg, and Pb) content did not exceed the permitted EU maximum. Granulation regimes were elaborated using a flat-die pelletizer, KAHL 14-175. The digestibility and the amount of produced gas emissions were determined using in vitro systems that recreate the digestion of small ruminants. The investigation proved that SBT leaves and stems are a unique underutilized source of animal feed, used alone or in combination with others. Twigs, due to their thorns, were granulated and valorized according to standards for application as fuel. The scheme offered in this study enables SBT agro-waste utilization and sustainable SBT berry production.

The twigs of sea buckthorn, blackcurrant, gooseberries, quince, and grapes were evaluated as a promising source of biologically active compounds—proanthocyanidins (PACs). Sea buckthorn twigs had the highest content of PACs (9.2% on dry biomass). Preliminary pretreatment of biomass with freon R134a did not allow an increase in PACs content in the composition of hydrophilic extract but confirmed the value of freon extract as an antibacterial agent against P. aeruginosa and B. cereus. The content of PACs was used as an indicator for assessment of the influence of hydrophilic extracts on pancreatic lipase activity. Under normal physiological conditions, in the presence of bile, the extract, which contained 42.4% of PACs was more effective compared to the extract which contained 17.5% of PACs. At all concentrations (0.2–40 mg of sample/g of pancreatic lipase), it inhibited lipase activity by 33%. Purified PACs were the most effective in inhibiting lipase activity (by 36%). However, in pathological physiological conditions (without bile), the opposite effect on lipase activity was observed. Thus, PACs and extracts can be used as inhibitors of pancreatic lipase only under normal physiological conditions.

In this paper, the dominance of the physical effects of ultrasound (US) pretreatment in improving the deligni-fication of wheat straw at a 1:20 solid/liquid (biomass/water) ratio is reported showing low-frequency/high power (25 kHz, 2 or 3 kW) as preferred conditions. The sonochemical pretreatment with alkali was identified as an optimal method to make the cellulose more susceptible to further enzymatic hydrolysis, thereby increasing the yield of soluble sugars. Previous bench-scale studies have shown that US pretreatment has a positive effect on delignification, nevertheless this has not yet been demonstrated on a larger scale. The objective of this study was to demonstrate the effectiveness of US pretreatment for wheat straw delignification from lab to semi-industrial scale (40 kg biomass) in terms of sugar yield and energy efficiency. A 59.2% of lignin removal was recorded after the cavitational treatment of wheat straw with a subsequent 68 +/- 5.7% yield in terms of enzymatic hydrolysis (52.6% glucose, 42.9% xylose and 4.5% arabinose).It was demonstrated that the positive effect of US alkali pretreatment of wheat straw on sugar yield was due to a combination of factors, including (i) an easier accessibility of the biomass carbohydrate network to enzymes due to the increased wheat straw porosity, (ii) the partial removal of lignin, which increases the relative pro-portion of carbohydrates in the treated biomass, and (iii) the disordering (amorphization) of the cellulose structure, which promotes carbohydrate hydrolysis as well as saponification of the acetyl groups in the hemi-cellulose. With respect to the Life Cycle Assessment (LCA) and the Cost Benefit Analysis the US pretreatment process herein reported was compared to an alternative Steam Explosion pretreatment. The results of the LCA analysis showed, that for all five environmental categories (energy consumption, global warming potential, water and fossil depletion, and the land occupation) the US pretreatment has advantages in comparison with the standard industrial Steam Explosion pretreatment.

Toxic formaldehyde emissions, and the necessity to reduce the consumption of petrochemicals, stimulates the development of environmentally friendly adhesives. The aim of this research was to study, for the first time, the possibility of using condensed tannins (CTs)-rich extracts from grey alder (Alnus incana) and black alder (Alnus glutinosa) bark in the production of particleboards and plywood adhesives. The chemical structure, composition, and molecular weight of the CTs were identified by a 13C-NMR and TOF-MS analysis. Three innovative adhesive systems were studied: CTs-phenol-formaldehyde (CTs-PF) resin; a CTs-polyethyleneimine (PEI) adhesive system; and CTs–PEI combined with an ultra-low emitting formaldehyde resin (ULEFR)—CTs–PEI–ULEFR. The results showed that CTs-PF resin has properties close to commercial PF resin, and the formaldehyde emission was twice lower. CTs–PEI bonded particleboards corresponded to the requirements of the EN 312:2010 standard for particleboards in dry conditions (Type P2). CTs–PEI–ULEFR, with a 40–60% substitution of ULEFR by CTs–PEI, had adhesive properties very close to ULEFR; the plywood shear strength fit the requirements of the EN 314-2:1993 standard for application in internal and external system conditions. The introduction of extracted alder bark residues microparticles into the composition of the adhesive system showed their positive potential for application as a filler.

For sustainable sea buckthorn (Hippophae rhamnoides) berry production, the task at hand is to find an application for the large amount of biomass waste arising at harvesting. Sea buckthorn (SBT) vegetation is currently poorly studied. The purpose of this research was to assess the composition and potential of SBT twigs as a source of valuable biologically active substances. Water and 50% EtOH extracts of twigs of three Latvian SBT cultivars with a high berry yield and quality, popular for cultivation in many countries (H. rhamnoides 'Maria Bruvele', 'Tatiana', 'Botanicheskaya Lubitelskaya'), were investigated for the first time. The phytochemical composition (UHPLC-ESI-MS/MS analysis) and biological activity of the obtained hydrophilic extracts were determined. The highest yield of polyphenolic compounds and serotonin was observed for 'Maria Bruvele'. Hydrophilic extracts were investigated for radical scavenging activity (DPPH˙ test), antibacterial/antifungal activity against five pathogenic bacteria/yeast, cytotoxicity, and the enzymatic activity of alpha-amylase (via in vitro testing), which is extremely important for the treatment of people with underweight, wasting, and malabsorption. The results showed a high potential of sea buckthorn biomass as a source of valuable biologically active compounds for the creation of preparations for the food industry, nutraceuticals, and cosmetics.

Most of biorefinery technologies are focused on the utilization of plant polysaccharides into chemicals, whereas lignin, the second most abundant natural polymer, is commonly used as a resource to generate power. This is the first report on flavones-bound lignin obtained by wheat straw (WS) pretreatment under low-frequency ultrasound (US) and hydrodynamic cavitation (HC) in sugar production processing. US and HC procedures carried out in aqueous 0.2–0.4% NaOH solutions and various liquid/biomass ratios strongly decreased the lignin content in the solid fraction by 30–45% and 25%, respectively, compared to non-treated WS. Moreover, НС pretreatment increased (approximately tenfold) the portion of ordered cellulose in residual biomass that could hinder the further enzymatic hydrolysis of WS. By means of sequential HC and US pretreatment the ordered cellulose content in solid fraction significantly decreased, compared to the HC alone. Furthermore, it was demonstrated that, after US pretreatment, hemicelluloses and oligomeric fragments of lignin and ligno-carbohydrate complexes were transferred into the liquid phase. In particular, tricin derivatives were detected in liquid fractions with a concentration of 30–35% on o.v.d. ash free sample, and more than 50 compounds associated with low-molecular-weight lignin fragments. These compounds were tentatively identified using high-resolution mass spectrometry (HR-MS) based fragmentation (sequencing) and a self-made database, showing that 16 out of 50 identified compounds belonged to the fragments of model lignin structural units. Tricin and low molecular weight lignin derivatives may find applications as strong antioxidants (i.e. lipidic systems). These findings proved that waste lignin streams obtained after cavitational processes could be a source of value-added products from WS conversion.

To provide wider use of wheat straw for energy production, microwave (MW) pre-treatment of wheat straw pellets was used to provide active control and improvement of the pellet structure and elemental composition. Wheat straw pellets were pre-treated at the temperature range of 473-573K using an originally designed rotating MW reactor. The effect of MW treatment on the wheat straw structural characteristics, element composition, ash content, and calorific values was analysed. The effect of wheat straw pre-treatment on the thermal decomposition of wheat straw pellets and blends with untreated wood pellets was experimentally studied. The yield of combustible volatiles was estimated varying pre-treatment temperatures and the mass fraction of pre-treated pellets in blends. The joint measurements of the weight loss rate of the fuel blends and the yield of combustible volatiles showed that MW pre-treatment of wheat straw pellets enhances the weight loss of blends up to 23% and the yield of combustible volatiles up to 400%. The results of the experimental study suggest that MW pre-treatment of wheat straw pellets can be used as a tool to provide effective control of the thermal decomposition of fuel blends.