Search Results (302)

In this paper, mussel shells were used to produce chitin, chitosan, and calcium acetate using chemical processes, searching for an alternative environmentally friendly biopolymer and calcium source. Mussel shells were treated with acetic acid as a demineralizing agent, resulting in separate solid fractions and calcium solution. The solid was further purified to produce chitin by deproteinization and decolorization processes, and then the deacetylation process was used to obtain chitosan. The calcium solution was evaporated to produce calcium acetate powder. The yields of extracted chitin, chitosan, and calcium acetate from 100 g of mussel shells were 2.98, 2.70, and 165.23 g, respectively. The prepared chitin, chitosan, and calcium acetate were analyzed by Fourier transform infrared (FTIR) spectrophotometry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) to confirm the chemical and physical properties. The analysis results of chitin and chitosan revealed the similarity to chitosan derived from crustaceans and insects in terms of functional group, structure and morphologies. The prepared calcium acetate shows FTIR and XRD data corresponding to calcium acetate monohydrate (Ca(CH₃COO)₂·H₂O) similar to synthesized calcium acetate in previous research. In addition, the mineral contents of calcium acetate identified by X-ray fluorescence (XRF) analysis exhibit 97.8% CaO with non-toxic impurities. This work demonstrated the potential of the production process of chitin, chitosan, and calcium acetate for the development of a sustainable industrial process with competitive functional performance against the commercial chitin and chitosan production process using crustacean shells and supported the implementation of a circular economy. Full article

Chitosan films with potential application in triboelectric nanogenerators (TENGs) represent a promising approach to replace non-biobased materials in these innovative devices. In the present work, chitosan with varying molecular weights (MW) and degrees of deacetylation was dissolved in aqueous acetic acid (AA) at different acid concentrations. It was observed that the MW had a greater influence on the viscosity of the solution compared to either the acid concentration or deacetylation degree. Gel formation occurred in high-MW chitosan solutions prepared with low AA concentration. Films prepared from chitosan solutions, through solvent-casting, were used to prepare TENGs. The power output of the TENGs increased with higher concentrations of AA used in the chitosan dissolution process. Similarly, the residual AA content in the dried films also increased with higher initial AA concentrations. Additionally, hot-pressing of the films significantly improves the TENG power output due to the decrease in morphological defects of the films. It was demonstrated that a good selection of the acid concentration not only facilitates the dissolution of chitosan but also plays a key role in defining the properties of the resulting solutions and films, thereby directly impacting the performance of the TENGs. Full article

Chitosan and technical cashew nutshell liquid (CNSLt) have emerged as promising natural compounds due to their antimicrobial, immunomodulatory, and fermentation-modulating properties. This study aimed to evaluate the inclusion of chitosan and CNSLt as potential substitutes for the ionophore monensin on feed intake, ruminal fermentation, nitrogen balance, and microbial protein synthesis in steers. Five crossbred steers (Bos taurus), 18 months old with an average body weight of approximately 350 kg and fitted with permanent ruminal cannulas, were assigned to a 5 × 5 Latin square design. The experimental diets consisted of: (1) control (CON), (2) monensin (MON; 25 mg/kg of dry matter [DM]), (3) chitosan (CHI; ≥850 g/kg deacetylation degree, 375 mg/kg DM), (4) CNSLt (500 mg/kg DM), and (5) CNSLt + CHI (500 + 375 mg/kg DM). Supplementation with CHI or CNSLt + CHI reduced the intake of dry matter, crude protein, and neutral detergent fiber. Additionally, fecal excretion of whole corn kernels increased in these treatments. Ruminal fermentation parameters were affected, with the CNSLt + CHI treatment promoting higher molar proportions of propionate and acetate, along with reduced estimated methane emissions. However, purine derivatives, microbial protein synthesis, and nitrogen balance were not significantly affected by any of the treatments. These results suggest that CNSLt and CHI, particularly when combined, may serve as effective natural alternatives to monensin in high-grain diets for ruminants. Full article

To mitigate the serious environmental impact caused by the persistent accumulation of plastics, replacing conventional plastics with paper-based alternatives has emerged as a promising trend. In response to the environmental and health concerns associated with petrochemical-based plastic meal boxes and fluorinated water- and oil-repellent agents, this study proposes a sustainable, fluorine-free coating technology based on chitosan to enhance the water and oil resistance of molded-paper pulp meal boxes. By adjusting the degree of deacetylation and the solution concentration of chitosan, coated meal boxes were fabricated via a spraying method. The results demonstrate that coatings prepared with highly deacetylated (>95%) and concentrated (4% w/v) chitosan significantly improve barrier properties, achieving a water contact angle of 114.9° ± 3°, the highest oil-resistance rating (12/12) according to TAPPI standards, and stable resistance to 95 °C hot oil for up to 30 min without leakage. In addition, the coated samples exhibit enhanced mechanical strength (21.26 MPa) and excellent biodegradability. This work provides a cost-efficient and eco-friendly disposable food packaging solution, facilitating the sustainable substitution of petrochemical-based plastics. Full article

Thermosensitive hydrogel, as a smart polymer material, showed great potential for application in the field of wound repair due to its unique external temperature responsiveness and excellent biocompatibility. Chitosan, a natural macromolecular polysaccharide derived from the deacetylation of chitin, possessed not only strong interactions with biomolecules such as DNA, proteins, and lipids, but also unique biocompatibility and degradability. Chitosan-based thermosensitive hydrogels, prepared by compounding chitosan with surfactants, underwent sol–gel phase transitions at varying external temperatures, which provided an ideal healing environment for wounds. This comprehensive review was initiated by elucidating the sol–gel phase transformation mechanism underlying thermosensitive hydrogels and the intricate process of wound repair. In addition, this review provided a detailed overview of the prevalent types of chitosan-based thermosensitive hydrogels, highlighting their unique characteristics and applications in different types of wound repair. Finally, the challenges and development directions of chitosan-based thermosensitive hydrogels in wound repair were discussed, aiming to provide theoretical support and practical guidance for their future applications in wound healing. Full article

Chitosan is recognized by its capacity to bind lipids based on the viscosity and degree of deacetylation. We analyzed the in vitro binding of Procambarus clarkii chitosan (PCC) with extra virgin olive oil and sunflower oil at temperatures and pH levels that approximate gastric-like conditions. In the tube test, 4 mg of PCC and 0.3 g of either EVO or of SO oils were mixed by stirring in test tubes with 4 mL of water acidified with HCl to a pH of 3. The PCC binding capability was determined by measuring the differences between the suspension without PCC and the suspension with PCC added. A scanning electron microscope (SEM) was utilized to further observe the uniformity and morphology of the emulsified PCC/oil hydrogels. In the test tube, PCC was shown to have a 1:11 (w/w) binding capacity for EVO and 1:15 (w/w) for SO. The SEM-based examination demonstrated a smooth surface with fine porosity of the microstructure of either PCC/oil hydrogel, proving successful emulsification. Under conditions similar to those in the stomach after a meal, including acidity, mixed composition, and temperature, PCC efficiently binds and emulsifies EVO and SO. Full article

The Miradero Water Treatment Plant (MWTP) in Mayagüez, Puerto Rico, uses sodium hypochlorite (SH) as a disinfectant. However, SH reacts with humic substances present in surface water, forming disinfection by-products (DBPs) regulated by the U.S. EPA. This study evaluated whether chitosan, a biopolymer with known bactericidal properties, could reduce chlorine demand and improve disinfection. Chitosan, with a 75% degree of deacetylation and a molecular weight of 460 kDa, was solubilized in four acids (acetic, citric, hydrochloric, and L-ascorbic) and tested under two turbidity ranges (236.0 and 2556 NTU). Chlorine demand curves were generated, and coliform presence–absence (P–A) tests were performed to assess bactericidal effects. Results showed that chitosan-treated samples achieved disinfection at the breakpoint with lower SH doses. For water with a turbidity of 236.0 NTU, all chitosan-acid solutions reached the breakpoint at 3.60 mg/L of SH. At 2556 NTU, three solutions required 4.20 mg/L SH, while hydrochloric acid–chitosan required only 3.60 mg/L. All chitosan-treated samples tested negative for coliforms, while controls treated with SH alone tested positive. These findings demonstrate that chitosan enhances bacterial removal and reduces chlorine demand, potentially lowering DBP formation in water treatment. Full article

Chitin and its deacetylated derivative, chitosan, are biopolymers of significant interest due to their biocompatibility, biodegradability, and wide-ranging applications in biomedical, environmental, and industrial fields. The exploitation of crustaceans as the traditional source of chitosan raises concerns about overfishing and ecological sustainability. Modern insect farming, in contrast, offers advantages such as a circular insect-based economy leading to a reduced carbon footprint. This review explores the potential of insect-derived chitosan as an alternative, emphasizing its environmental benefits during production, functional properties, and potential applications. Several aspects of key analytical techniques for chitin and chitosan characterization, including photometric, chromatographic, and spectroscopic methods, are also discussed. The review underscores the versatility of insect-derived chitosan in biomedical applications, including wound healing and drug delivery, as well as its potential in agriculture, packaging, and wastewater treatment. Full article

Antimicrobial resistance (AMR) is a major global health problem, exacerbated by the excessive and inappropriate use of antibiotics in human medicine, animal care and agriculture. Therefore, new strategies and compounds are needed to overcome this issue. In this view, it may be appropriate to reconsider existing biomaterials to alleviate antibiotic overuse. Chitin, a naturally abundant amino mucopolysaccharide, is a poly-β-1, 4-N-acetylglucosamine (GlcNAc). It is a white, hard, inelastic, nitrogenous polysaccharide and the major source of surface pollution in coastal areas. Chitosan derives from the partial N-deacetylation of chitin and originates from the shells of crustaceans and the fungi cell walls. It is a nontoxic natural antimicrobial polymer approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitin and chitosan, as non-toxic biopolymers, are useful compounds for wastewater treatment to remove pollutants, such as pharmaceuticals, heavy metals and dyes. The described features make these biopolymers intriguing compounds to be investigated for their application as antibacterials. Full article

Chitosan (CS), a versatile biopolymer obtained through the deacetylation of chitin, has gained significant interest in biomedical and pharmaceutical applications due to its biocompatibility, biodegradability, and unique gel-forming capabilities. This review comprehensively analyzes CS-based gel development, covering its extraction from various natural sources, gelation mechanisms, and biomedical applications. Different extraction methods, including chemical, biological, and green techniques, are discussed regarding efficiency and sustainability. The review explores the physicochemical properties of CS that influence its gelation behavior, highlighting various gelation mechanisms such as physical, ionic, and chemical cross-linking. Recent advances in gel formation, including Schiff base reactions, Diels–Alder click chemistry, and thermosensitive gelation, have expanded the applicability of CS hydrogels. Furthermore, CS-based gels have demonstrated potential in wound healing, tissue engineering, drug delivery, and antimicrobial applications, offering controlled drug release, enhanced biocompatibility, and tunable mechanical properties. The incorporation of nanomaterials, bioactive molecules, and functional cross-linkers has further improved hydrogel performance. The current review underscores the growing significance of CS-based gels as innovative biomaterials in regenerative medicine and pharmaceutical sciences. Full article

As a biodegradable material, chitin possesses exceptional physical and chemical properties, making it valuable in various industrial sectors. Compared to chitin, its derivative, chitosan, offers even more versatile applications due to its higher solubility and reactivity. As the key precursor for chitosan production, chitin is typically harvested from shrimp and crab exoskeletons. However, the quest for alternative sources has intensified to reduce reliance on crustacean-derived chitin. Black soldier fly (BSF, Hermetia illucens), particularly its puparium, has emerged as a promising alternative, though it is typically considered waste. In this study, we investigated different combinations and sequences of extraction treatments for chitin from the BSF puparium. The results demonstrate that sequential treatments of demineralization (DM), deproteination (DP), and decolorization (DC) produce chitin with the lowest ash, lipid, and protein contents—approximately 1.01%, 1.99%, and 3.01%, respectively, yielding degrees of DM and DP at 94.77% and 92.24%, and a chitin purity of 93.98%. In contrast, combining DP and DC following the DM treatment facilitates partial chitosan transformation with a degree of deacetylation (DD) of 65.90%, offering a direct alternative for producing chitosan without an additional deacetylation process. Full article

Excessive blood loss is a leading cause of mortality among soldiers and accident victims. The wound healing process typically ranges from three weeks to several months, with disruptions in healing stages potentially prolonging recovery time. Chronic wounds may persist for years, creating a favorable environment for microbial growth. Chitosan, a derivative of chitin—the second most abundant biopolymer in nature—is obtained through deacetylation and exhibits mucoadhesive, analgesic, antioxidant, biodegradable, non-toxic, and biocompatible properties. Due to its hemostatic and regenerative support capabilities, chitosan is widely applied in the food, cosmetic, and agricultural industries; environmental protection; and as a key component in dressings for chronic wound healing. Notably, its antibacterial properties make it a promising candidate for novel biomaterials to replace traditional antibiotics and prevent the emergence of drug-resistant strains. The primary aim of this study was the chemical cross-linking of chitosan with the amino acids L-aspartic and L-glutamic acid in the presence of periclase (magnesium oxide) under microwave radiation conditions. Subsequent research stages involved the analysis of the samples’ physicochemical properties using SEM, FT-IR, XPS, atomic absorption spectrometry, swelling behavior (in water, SBF, and blood), porosity, and density. Biological assessments included biodegradation, cytotoxicity, and antibacterial activity against Escherichia coli and Staphylococcus aureus. The obtained results confirmed the high potential of the newly developed hemostatic agents for effective hemorrhage management under non-sterile conditions. Full article

Chitin and chitosan, versatile biopolymers extensively used in the food and cosmetic industries, are traditionally sourced from crustaceans. However, fungi such as Agaricus bisporus mushrooms present a sustainable, non-animal alternative. This study explored the potential of different Agaricus bisporus samples, including fresh mushrooms and production residues, as sources of chitin. Given that Agaricus bisporus mushrooms are also a rich source of ergosterol, the study additionally incorporated samples treated with supercritical carbon dioxide (scCO₂). The effects of deproteinisation conditions—specifically the number of successive extractions, sodium hydroxide concentration, and extraction time—were evaluated for fresh mushroom samples in terms of alkali-insoluble matter, chitin yields, and the degree of deacetylation (DD), with the latter determined by Fourier-transform infrared spectroscopy. The results indicated that extraction time had no statistically significant impact on AIM or chitin yield, while the DD increased with prolonged extraction, plateauing after 60 min. Higher sodium hydroxide concentrations enhanced deacetylation, but adversely affected extraction yields. No significant differences in chitin’s DD were observed between fresh mushroom and production residue samples, regardless of scCO₂ treatment. This study demonstrates the viability of recovering chitin from Agaricus bisporus mushroom bio-residues, including those treated with scCO₂, offering a sustainable and eco-friendly alternative for chitin production. Full article

Sourcing and batch differences are often cited as intrinsic drawbacks for all natural polymers. Chitosan makes no exception. Chitosan is a biocompatible and biodegradable biopolymer with high potential for several biomedical applications, especially for releasing drugs and bactericidal and virucidal agents. Despite the potential of chitosan as a matrix for producing antibacterial films, the variability in its composition, stemming from its natural sources, can hinder the translation from bench to industry. To overcome this concern, we conducted a study to access the interchangeability of chitosan for the development of antibacterial drug release systems, in particular one system crosslinked with tannic acid and iron sulfate. Chitosans from different suppliers were characterized and used to synthetize films containing gentamicin, according to a previously reported protocol. The impact of molecular weight (M_W), deacetylation degree and purity on film properties and antibiotic release kinetics was assessed and results were compared. The films exhibited different initial bursts followed by similar sustained release profiles. All films exhibited antibacterial activity against both E. coli and S. aureus for at least 42 days. Moreover, films were cyto- and hemocompatible. Therefore, despite some differences in physicochemical properties, the interchangeability among the studied chitosan suppliers to produce antibacterial films is feasible, and the final product properties and performances are not significantly altered. Full article