Search Results (16)

Lignin, the second most abundant natural polymer, is a by-product of the biorefinery and pulp and paper industries. This study was undertaken to evaluate the properties and estimate the prospects of using lignin as a by-product of the pretreatment of common reed straw (Phragmites australis) with deep eutectic solvents (DESs) of various compositions: choline chloride/oxalic acid (ChCl/OA), choline chloride/lactic acid (ChCl/LA), and choline chloride/monoethanol amine (ChCl/EA). The lignin samples, hereinafter referred to as Lig-OA, Lig-LA, and Lig-EA, were obtained as by-products after optimizing the conditions of reed straw pretreatment with DESs in order to improve the efficiency of subsequent enzymatic hydrolysis. The lignin was studied using gel penetration chromatography, UV-vis, ATR-FTIR, and ¹H and ¹³C NMR spectroscopy; its antioxidant activity was assessed, and the UV-shielding properties of lignin/polyvinyl alcohol composite films were estimated. The DES composition had a significant impact on the structure and properties of the extracted lignin. The lignin’s ability to scavenge ABTS^+• and DPPH^• radicals, as well as the efficiency of UV radiation shielding, decreased as follows: Lig-OA > Lig-LA > Lig-EA. The PVA/Lig-OA and PVA/Lig-LA films with a lignin content of 4% of the weight of PVA block UV radiation in the UVA range by 96% and 87%, respectively, and completely block UV radiation in the UVB range. Full article

Rapid extraction and concentration systems based on green materials such as cellulose or lignin are promising. However, there is still a need to optimize the material properties and production processes. Unlike conventional cellulose or lignin sorbent materials, aquatic reed root cells can concentrate external organic pollutants in the water and accumulate them in the plant. Inspired by this, a new nanocellulose–lignin aerogel (NLAG) was designed, in which nanocellulose was used as a substrate and lignin and polyamide epoxy chloropropane were used to crosslink cellulose in order to enhance the strength of the NLGA, resulting in good mechanical stability and water–oil amphiphilic properties. In practical applications, the organic membrane on the NLAG can transport organic pollutants from water to the NLAG, where they are immobilized. This is evidenced by the fact that the aerogel can remove more than 93% of exogenous phenol within a few minutes, highly enriching it inside. In addition, the aerogel facilitates filtration and shape recovery for reuse. This work establishes a novel biopolymer–aerogel-based extraction system with the advantages of sustainability, high efficiency, stability, and easy detachability, which are hard for the traditional adsorbent materials to attain. Full article

The current work presents a sustainable, environmentally friendly method for lignin extraction by applying deep eutectic solvents (DES), which are biodegradable. The Solid-DES extraction (SDESE) method of recovering lignin from reeds is presented. DES based on betaine hydrochloride and lactic acid (BeHCl, LA) was prepared and applied in SDESE at a ratio of 1:20 wt %. Fourier-transform infrared spectroscopy (FTIR) was used to characterize the materials. The DES-extracted lignin (DEL) from the reeds exhibited an interesting structure due to the rearrangement of syringyl, guaiacyl, and parahydroxyphenyl units that occurred as a result of DES breaking the initial raw material structure. Full article

Giant reed is a non-food, tall, rhizomatous, spontaneous perennial grass that is widely diffused in warm-temperate environments under different pedo-climatic conditions. In such environments, it is considered one of the most promising energy crops in terms of economic and environmental sustainability, as it can also be cultivated on marginal lands. Owing to its complex and recalcitrant structure due to the lignin content, the use of giant reed as a feedstock for biogas production is limited. Thus, pre-treatment is necessary to improve the methane yield. The objective of this review was to critically present the possible pre-treatment methods to allow the giant reed to be transformed in biogas. Among the studied pre-treatments (i.e., hydrothermal, chemical, and biological), alkaline pre-treatments demonstrated better effectiveness in improving the methane yield. A further opportunity is represented by hybrid pre-treatments (i.e., chemical and enzymatic) to make giant reed biomass suitable for bio-hydrogen production. So far, the studies have been carried out at a laboratory scale; a future challenge to research is to scale up the pre-treatment process to a pilot scale. Full article

The perennial rhizomatous grass giant reed (Arundo donax L.) can be exploited to produce hydrogen by dark fermentation. This implies a high availability of simple sugars, like glucose and xylose, and, thus, a pre-treatment is necessary to remove lignin and expose the holocellulose to enzymatic attack. This study aimed at evaluating the hydrogen production from giant reed hydrolysates. Giant reed dry meal was pre-treated with diluted NaOH (1.2% weight/weight), then the solid fraction was separated from the alkaline black liquor by filtration, enzymatically hydrolyzed with a cellulase blend (Cellic CTec2), and fermented in mesophilic batch conditions with a microbial consortium derived from pig slurry. The impact on hydrogen yield of initial pH was evaluated by comparing the hydrogen production from hydrolysates with not adjusted (5.3) or adjusted initial pH (8.7) using NaOH or alkaline black liquor. The highest hydrogen yield, 2.0 mol/mol of hexoses, was obtained with alkaline initial pH 8.7, regardless of how the pH adjustment was managed. The yield was 39% higher than that obtained in reactors with initial pH 5.3. In conclusion, thermo-alkaline pre-treatment followed by enzymatic saccharification and initial pH adjustment at 8.7 with the black liquor remaining after pre-treatment is a promising strategy to produce hydrogen from giant reeds in dark fermentation. Full article

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120 °C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture. Full article

Increasing energy demands and fossil fuel consumption causing global warming has motivated research to find alternative energy sources such as biofuels. Giant reed (Arundo donax L.), a lignocellulosic, perennial, rhizomatous grass has been proposed as an important bioenergy crop for advanced biofuel in the Mediterranean area. Anaerobic digestion for advanced biomethane seems to be a promising approach. However, the presence of lignin in lignocellulosic biomass represents the main obstacle to its production (due to its recalcitrance). Thus, to use effectively lignocellulosic biomass in anaerobic digestion, one or more pretreatment steps are needed to aid microorganisms access to the plant cell wall. To this end, the present study investigated the effect of fungal pretreatment of giant reeds obtained from two different harvesting time (autumn and winter) on biomethane production by anaerobic digestion using two white rot fungi (Pleurotus ostreatus and Irpex lactus, respectively). The highest biomass lignin degradation after 30 days incubation with P. ostreatus in both autumn (27.1%) and winter (31.5%) harvest time. P. ostreatus pretreatment showed promising results for anaerobic digestion of giant reed achieving a cumulative yield of 130.9 NmL g⁻¹ VS for the winter harvest, whereas I. lacteus showed a decrease in methane yield as compared with the untreated biomass (77.4 NmL g⁻¹ VS and 73.3 NmL g⁻¹ VS for winter and autumn harvest, respectively). I. lacteus pretreatment resulted in a loss of both holocellulose and lignin, indicating that this strain was less selective than P. ostreatus. Further studies are necessary to identify white rot fungi more suitable to lignocellulosic biomass and optimize biological pretreatment conditions to reduce its duration. Full article

Several experimental datasets available on the gasification of different lignocellulosic feedstocks were used to correlate the flow of gasifying agents with the performance of updraft gasification in an autothermic 200 kWth pilot plant. The feedstocks used included eucalyptus wood chips, torrefied eucalyptus and spruce chips, lignin rich residues from biorefined straw and reed, shells of almond and hazelnut, which were gasified in flows of air, air and steam, oxygen, oxygen and steam. Thermal profiles inside the gasifier and gas quality in terms of incondensable gas and tar content were recorded and used to calculate the energy efficiency of converting solid feedstock into gaseous and liquid carriers. Common behaviors and parametric functionalities were identified to better understand the process and the most efficient tools to achieve the desired products. In analyzing data, the ratio steam to biomass was reported in terms of the equivalence ratio, ER(H₂O) i.e., the fraction of the stoichiometric quantity required to convert the feedstock into H₂ and CO₂. The use of steam was useful to stabilize the process and to tune the H₂/CO ratio in the syngas which reached the value of 2.08 in the case of oxy-steam gasification of lignin rich residues at ER(H₂O) of 0.25. Larger use of steam depressed the process by lowering the average temperature of the bed, which instead increased steadily with ER(O₂). The production of tar depends on the biomass type and a substantial reduction can be achieved with the torrefaction pretreatment. The same effect was observed increasing the residence time of the syngas in the reactor, typically achieved using oxygen instead of air as main gasification flow or reducing the ER(H₂O). Oxy-steam gasification of torrefied wood led to the best results in terms of cold gas efficiency and low heating value when carried out in the ranger 0.23–0.27 of both the ERs. Full article

The search for sustainability has led to the utilization of more ecological materials with at least, a similar structural performance to those used at present. In this regard, reed fits the environmental and structural requirements as it is a sustainable and biodegradable lignin-cellulose material with remarkable mechanical properties. This research confirms the reed’s structural efficiency as it demonstrates that it has excellent strength and stiffness in relation to its density. The reed anisotropy has a large impact on its properties. Indeed, the strength and stiffness parallel to the fibers are clearly higher than in the perpendicular direction. The results confirm that strength and stiffness decrease with the moisture content and nodes act as reinforcement in compression and bending. If compared with steel, timber and concrete, the reed possesses the highest value for strength. Hence, reed constitutes a strong candidate for environmentally friendly engineering. Full article

The biogas production through the anaerobic digestion (AD) of giant reed (Arundo donax L.) biomass has received increasing attention. However, due to the presence of lignin, a low CH₄ yield can be obtained. Aiming to improve the CH₄ yield from giant reed biomass, the effectiveness of a thermo-chemical pre-treatment based on KOH was evaluated in this paper. The usefulness of a washing step before the AD was also assessed. The pre-treatment led to a specific CH₄ yield up to 232 mL CH₄ g⁻¹ VS which was 21% higher than that from untreated biomass; the maximum daily rate of production was improved by 42%, AD duration was reduced by 10%, and CH₄ concentration in the biogas was increased by 23%. On the contrary, the washing step did not improve the AD process. Besides, washing away the liquid fraction led to biomass losses, reducing the overall CH₄ production. The use of a KOH-based pre-treatment appears as a good option for enhancing the AD of giant reed, also presenting potential environmental and agronomical benefits, like the avoidance of salty wastewater production and the likely improvement of the digestate quality, due to its enriched K content. Full article

Recently, several chemical and physical treatments were developed to improve different properties of wood. Such treatments are applicable to many types of cellulose-based materials. Densification leads the group in terms of mechanical results and comprises a chemical treatment followed by a thermo-compression stage. First, chemicals selectively etch the matrix of lignin and hemicellulose. Then, thermo-compression increases the packing density of cellulose microfibrils boosting mechanical performance. In this paper, in comparison with the state-of-the-art for wood treatments we introduce an additional nano-reinforcemeent on densified giant reed to further improve the mechanical performance. The modified nanocomposite materials are stiffer, stronger, tougher and show higher fire resistance. After the addition of nanoparticles, no relevant structural modification is induced as they are located in the gaps between cellulose microfibrils. Their peculiar positioning could increase the interfacial adhesion energy and improve the stress transfer between cellulose microfibrils. The presented process stands as a viable solution to introduce nanoparticles as new functionalities into cellulose-based natural materials. Full article

The cooperative thermomechanical properties of plant-derived polymers have been studied insufficiently, although this feedstock has a very high potential. In the present paper, we analyzed the changes in the structure and physicochemical properties of lignin-rich biomass induced by thermomechanical pretreatment. Low-temperature treatment allows one to retain the original supramolecular structure of the cell walls, while an appreciably high disintegration degree is reached. This increases the reactivity of the material in the subsequent heterogeneous reactions. Mechanical pretreatment at medium temperatures (10 °C), when almost all cell wall polymers except for low-molecular-weight lignin are in the glassy state, enhances the mobility of cell wall polymers and causes sufficient cellulose disordering, while the specific surface area is not significantly increased. High-temperature pretreatment of reed biomass is accompanied by pore formation and lignin release from the cell wall structure, which opens up new prospects for using this biomass as a matrix to produce core–shell-structured sorbents of heavy metals. The energy consumed by mechanochemical equipment for the activation of reed biomass was determined. Full article

Cosmetic products are generally formulated as emulsions, ointments, solutions or powders containing active ingredients. According to EU legislation, a cosmetic product is “any substance or preparation intended to be placed in contact with the various external parts of the human body with a view exclusively or mainly to cleaning, perfuming them, changing their appearance, and/or correcting body odors and/or protecting them or keeping them in good conditions”. However, science advancement in both active carriers and ingredients has streamlined the process through which many cosmetic products by their delivery systems can induce modifications on the skin physiology. This is the reason why Reed and Kligman redefined these products as “cosmeceuticals”, which refers to the combination of cosmetics and pharmaceuticals. Until recently, the term of cosmeceuticals has not had legal significance. The so-called cosmeceuticals, in fact, may induce modifications on the skin physiology, modifying, for example, transepidermal water loss, keratinocytes cohesion and turnover, modulating the inflammatory cascade, and/or altering the surface microbiota by the activity of the preservatives content. For these reasons, they are claimed to have medical or drug-like benefits. Naturally, their effectiveness on minor skin disorders or mild skin abnormalities has to be shown by in vitro and in vivo studies. On the other hand, their formulations contain emulsifiers, preservatives, and other chemicals which, by their cumulative use, may provoke side effects, such as allergic and/or sensitization phenomena. Moreover, many ingredients and packaging for such products are not biodegradable. In this study, we would like to introduce an innovative category of cosmeceuticals made by biodegradable nonwoven tissues. These cosmeceutical tissues, produced through the use of natural fibers, may bind different active ingredients and therefore become effective as antibacterial, anti-inflammatory, sun-protective, whitening, or anti-aging products, depending on the ingredient(s) used. Differently from the usual cosmetics, they do not contain preservatives, emulsifiers, colors, and other chemicals. They can be applied as dried tissue on wet skin, remaining in loco for around 30 min, slowly releasing the active ingredients entrapped into the fibers. It is interesting to underline that the tissue, acting as a carrier, has its own effectiveness via chitin and lignin polymers with an antibacterial and anti-inflammatory activity. When hydrolyzed by the human microbiota enzymes, they give rise to ingredients used as cell nourishment or energy. This paper will review part of the scientific research results, supporting this new category of biodegradable cosmetic products known as facial mask sheets. Full article

Hydrodynamic cavitation was recently applied as a biomass pretreatment method. Most of the studies which used hydrodynamic cavitation were applied to pretreated sugarcane bagasse or reed. High biomass yield of Sida hermaphrodita points out the necessity of studies on its effective pretreatment before methane fermentation, especially because its “wood-like” characteristics could present different disintegration properties than other lignocellulose biomass. Thus, the aim of the study was to investigate the influence of duration of hydrodynamic cavitation on lignocellulose composition in Sida hermaphrodita silage, and the assessment of disintegrated biomass as a substrate for methane fermentation. The study showed a slight decrease in lignin, cellulose, and hemicellulose content in biomass after hydrodynamic cavitation, which resulted in a higher content of carbohydrates in the liquid fraction of disintegrated substrates. Methane production was 439.1 ± 45.0 L CH₄/kg total solids (TS) from the substrate disintegrated for 20 min. However, the most effective time for methane production was hydrodynamic cavitation of the substrate for 5 min. At this pretreatment duration, the highest values for chemical oxygen demand (COD), total organic carbon (TOC), and carbohydrate reduction were also noted. The study proved that hydrodynamic cavitation applied for 5 min allowed obtaining an energy profit of 0.17 Wh/g TS. The studies on a laboratory scale indicated that the technology of hydrodynamic cavitation of Sida hermaphrodita could be economically applied for methane fermentation on a large scale. Full article

Hydrothermal carbonization (HTC), as an environmental friendly process, presents wide potential applicability for converting biomass to biochar with high energy density. Reed, a major energy crop, was converted by a HTC process in a batch reactor at 200–280 °C for 0.5 to 4 h. Biochar mass yield changed from 66.7% to 19.2% and high heating value (HHV) from 20.0 kJ/g to 28.3 kJ/g, respectively, by increasing the carbonization temperature from 200 °C to 280 °C and decreasing the residence time from 2 h to 1 h. The Fourier Transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM) results indicated the lignocellulosic crosslink structure of reed is broken and biochar having a high energy density is obtained with the increase of temperature. The microcrystal features of reed are destroyed and biochar contained mainly lignin fractions. The HTC of biocrude is carried out at 200–280 °C for 2.0 h and the results showed that the obtained biochar has uniform particles filled with carbon microspheres. Full article