Research on lignin deconstruction has recently become the center of interest for scientists and companies worldwide, racing towards harvesting fossil-fuel like aromatic compounds which are so durably ...put together by plants as products of millions of years of evolution. The natural complexity and high stability of lignin bonds (also as an evolutionary adaptation by plants) makes lignin depolymerization a highly challenging task. Several efforts have been directed towards a more profound understanding of the structure and composition of lignin in order to devise pathways to break down the biopolymer into useful compounds. The present contribution aims to provide an overview of key advances in the field of lignin depolymerisation. Protocols and technologies will be discussed as well as critically evaluated in terms of possibilities and potential for further industrial implementation.
Research on lignin deconstruction has recently become the center of interest for scientists and companies worldwide, racing towards harvesting fossil-fuel like aromatic compounds which are so durably put together by plants as products of millions of years of evolution.
Hydrogels have become one of the potential polymers used with great performance for many issues and can be promoted as biomaterials with highly innovative characteristics and different uses. Gelatin ...is obtained from collagen, a co-product of the meat industry. Thus, converting wastes such as cartilage, bones, and skins into gelatin would give them added value. Furthermore, biodegradability, non-toxicity, and easy cross-linking with other substances can promote polymers with high performance and low cost for many applications, turning them into sustainable products with high acceptance in society. Gelatin-based hydrogels have been shown to be useful for different applications with important and innovative characteristics. For instance, these hydrogels have been used for biomedical applications such as bone reconstruction or drug delivery. Furthermore, they have also shown substantial performance and important characteristics for remediation for removing pollutants from water, watercourse, and effluents. After its uses, gelatin-based hydrogels can easily biodegrade and, thus, can be sustainably used in the environment. In this study, gelatin was shown to be a potential polymer for hydrogel synthesis with highly renewable and sustainable characteristics and multiple uses.
•Investigation on nanocellulose moves towards the use of lignocellulosic biowastes.•Agroindustrial residues as profitable nanocellulose supply chain for the future.•Sustainable valorization of ...agricultural activities and industrial processes.•Nanocellulose production within a biorefinery concept.
In recent years the nanocellulose has become an important topic for several research fields due to its renewability, availability, biocompatibility and different awesome properties. As occurs with first and second generation bioethanol, the investigation on nanocellulose is gradually going towards the indirect use of lignocellulosic biomass, i.e. the exploitation of different cellulosic residues and wastes produced from agricultural and industrial activities because of the wide availability and renewable character of these feedstocks. In the present review, an exhaustive bibliographic study was performed to prove the increasing interest on these new cellulose sources. Furthermore, and according to existing literature about nanocellulose obtaining, the new properties and possibilities that this new feedstock offers were discussed, and the advantages due to the use of this kind of raw materials were presented. Finally, overlooking the valorization of existing agricultural activities and industrial processes, a scheme of the proper use of these agricultural and industrial wastes as a future nanocellulose supply chain was proposed.
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•A factorial design of 3 levels was used to synthesize physical PVA-lignin hydrogels.•Six synthesis routes were statistically evaluated to find optimal formulations.•FTIR showed a ...good compatibility between PVA and lignin.•Addition of lignin enhanced the swelling capacity of hydrogels up to 800%.•Lignin did not affect the compression integrity of the samples.
Lignin is an excellent candidate to be used as a starting material for hydrogel synthesis due to its highly functional character. The exhaustible character of the fossil resources linked to the increase of plastic residues in the environment encourages an intensive research on biorenewable and biodegradable polymers to synthesize new materials. Taking into account this current scenario, this work searches for new green routes to elaborate physical hydrogels with excellent capacity of swelling and suitable consistency. To this end, lignin and poly(vinyl alcohol) were blended in different proportions following a three-level-two-factorial design and using six different routes of crosslinking and drying for each set of experiments. The hydrogels formed under the optimal conditions were characterized by FTIR, SEM, XRD, DSC and TGA and their mechanical properties were also evaluated by compression tests. The selected optimum synthesis routes enabled the obtaining of physically crosslinked hydrogels with up to 800% water retention ability. FTIR spectra confirmed the interactions between lignin and PVA showing shifts and modifications on the characteristic bands of the raw polymers. Compression tests showed that all the hydrogels kept complete integrity even compressing them up to an 80% of their initial thickness.
The growing concern about the environmental impact and human health risk related to the excessive use of synthetic ingredients in cosmetics and topical formulations calls for the exploration of safe ...and sustainable natural alternatives. Lignin-rich lignocellulosic industrial wastes such as hazelnut and walnut shells were used as a lignin polymer source. Agro-derived lignins were evaluated as a potential natural active ingredient for health care products. Aside from the structural characteristics of isolated lignins, which were identified by GPC, Py-GC-MS, and 2D HSQC NMR techniques, functional properties such as antioxidant power and UV absorption ability were investigated. The SPF values found for creams containing 5% of hazelnut and walnut lignin content were 6.9 and 4.5, respectively. Additionally, both lignin types presented appropriate protection against UVA radiation, highly interesting property to block the full ultraviolet spectrum. The biological activity of isolated lignins assessed at different concentrations (0.01-1 mg/mL) and different times (24, 48, and 72 h) on murine fibroblast cell line 3T3 suggested their suitability for cosmetic applications.
The purpose of this work was to evaluate and compare the role of different nano-chitin morphologies on the structural and functional properties of thermoplastic starch-based films prepared by ...casting-evaporation approach. The introduction of chitin nano-objects – nanocrystals (CHNC) and nanofibers (CHNF) in concentrations of 5–20% – in thermoplastic starch-based matrices resulted in the enhancement of the final properties of the nanocomposite films in a morphological-dependent manner. The obtained data clearly demonstrate that the nanocomposite films elaborated with chitin nano-objects showed superior mechanical, thermal, barrier and antifungal properties as compared to those prepared with unfilled thermoplastic starch films. Furthermore, chitin nano-objects content, shape and size, were found to be an important role to the final properties of the thermoplastic starch nanocomposite films. Our findings highlight the potential use of such chitin nano-objects in thermoplastic starch-based matrices to be applied in functional food coatings and packaging.
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•Starch nanocomposite films were prepared with chitin nanocrystals and nanofibers.•Starch nanocomposite films showed better mechanical properties than starch matrix.•Starch nanocomposite films displayed better barrier properties than starch matrix.•Starch nanocomposite films presented fungistatic activity against Aspergillus niger.•Nanocomposite films prepared with chitin nanofibers showed better final properties.
In the present work, the optimization of the extraction of antioxidant compounds from apple pomace using ultrasound technology as an environmentally friendly and intensification process was ...developed. Different sonication powers, extraction temperatures and extraction times were studied and their influence on extraction yield and characteristics of the extracted samples (total phenolic compounds, flavonoid content and antioxidant capacity) are presented. The elaborated experimental design and the analysis of Pareto and response surface diagrams allowed us to determine the optimal extraction conditions. The conditions that allow the maximum extraction of phenolic compounds were found at 20 min, 90 °C and 50% ultrasound amplitude. Nevertheless, at these conditions, the antioxidant capacity measured by DPPH decreased in the extracted samples.
•Vine shoots were tested for prebiotic oligosaccharides (OS) production.•Membrane processing allowed to remove a high percentage of impurities.•Purified OS were characterized by HPLC, FTIR, ...HPAEC-PAD, MALDI-TOF and UPLC-ESI-MS.•Purified OS were assayed for prebiotic activity showing bifidogenic effect.
Vine shoots were subjected to a hydrothermal treatment to cause the selective solubilisation of the hemicelluloses. The hemicelluloses solubilisation products were refined by a sequential processing with nanofiltration and ion exchange obtaining a refined product with a purity of 99%. A depth chemical and structural characterization of the purified oligosaccharide mixture from vine shoots was performed for the first time by HPLC, FTIR, HPAEC-PAD, MALDI-TOF and UPLC-DAD-ESI-MS. The characterization showed the presence of oligosaccharide mixtures with a wide polymerization degree (DP = 2–17) and a rich substitution pattern. Moreover, the thermal behaviour of the mixture was evaluated by TGA in order to obtain information about the thermal and storage conditions during its incorporation into processed functional foods. The thermal and acid stability of the obtained oligosaccharides was also evaluated corroborating their resistance to the digestive conditions. The assessment of the prebiotic activity of the digested mixture was carried out by in vitro fermentability with faecal inocula from human volunteers by the monitoring of short chain fatty acids production and the population dynamic of bifidobacteria by FISH.
As air pollution escalates, the need for air filters increases. It is better that the filters used be based on natural fibers, such as non-wood fibers, which cause low damage to the environment. ...However, the short fiber lengths, low apparent densities, and high volumes of non-wood materials can make it challenging to prepare filter paper with the required mechanical and physical properties. In that context, this study focused on utilizing bamboo fibers to fabricate filter paper by employing the anthraquinone soda pulping method. The pulp underwent bleaching and oxidation processes, with the incorporation of cationic starch (CS) and polyvinyl alcohol (PVA) to enhance resistance properties, resulting in the creation of handmade filter papers. The findings revealed that the tear, burst, and tensile strength of filter paper increased with the oxidation and addition of CS and PVA. Air permeability increased with addition of PVA and combination of CS and PVA. FTIR demonstrated the conversion of hydroxyl groups in cellulose chains to carboxyl groups due to oxidation. SEM images illustrated alterations in the fiber structure post-oxidation treatment, with CS reducing pores while PVA and the CS-PVA combination enlarged pore size and enhanced porosity. The BET surface area surface area expanded with oxidation and the addition of the CS-PVA blend, indicating heightened filter paper porosity. Notably, the combined inclusion of CS and PVA not only augmented mechanical strength but also increased porosity while maintaining pore size.
Chitosan films lack various important physicochemical properties and need to be supplemented with reinforcing agents to bridge the gap. Herein, we have produced chitosan composite films supplemented ...with copolymerized (with polyacrylonitrile monomers) cellulose nanofibers and diatomite nanocomposite at different concentrations. The incorporation of CNFs and diatomite enhanced the physicochemical properties of the films. The mechanical characteristics and hydrophobicity of the films were observed to be improved after incorporating the copolymerized CNFs/diatomite composite at different concentrations (CNFs: 1%, 2% and 5%; diatomite: 10% and 30%). The antioxidant activity gradually increased with an increasing concentration (1–5% and 10–30%) of copolymerized CNFs/diatomite composite in the chitosan matrix. Moreover, the water solubility decreased from 30% for chitosan control film (CH-0) to 21.06% for films containing 30% diatomite and 5% CNFs (CNFs-D30-5). The scanning electron micrographs showed an overall uniform distribution of copolymerized CNFs/diatomite composite in the chitosan matrix with punctual agglomerations.
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•Chitosan films alone lack various important physicochemical properties.•Films were produced with copolymerized CNFs and diatomite nanocomposite.•CNFs and diatomite notably enhanced the physicochemical properties of the films.•The films were visually transparent up to an acceptable level.
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