Physicochemical Properties of Chitin and Chitosan Produced from Medicinal Fungus (Fomitopsis pinicola)

Multiple Technology Approach Based on Stable Isotope Ratio Analysis, Fourier Transform Infrared Spectrometry and Thermogravimetric Analysis to Ensure the Fungal Origin of the Chitosan

Chitosan is a natural polysaccharide which has been authorized for oenological practices for the treatment of musts and wines. This authorization is limited to chitosan of fungal origin while that of crustacean origin is prohibited. To guarantee its origin, a method based on the measurement of the stable isotope ratios (SIR) of carbon δ¹³C, nitrogen δ¹⁵N, oxygen δ¹⁸O and hydrogen δ²H of chitosan has been recently proposed without indicating the threshold authenticity limits of these parameters which, for the first time, were estimated in this paper. In addition, on part of the samples analysed through SIR, Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA) were performed as simple and rapid discrimination methods due to limited technological resources. Samples having δ¹³C values above -14.2‱ and below -125.1‱ can be considered as authentic fungal chitosan without needing to analyse other parameters. If the δ¹³C value falls between -25.1‱ and -24.9‱, it is necessary to proceed further with the evaluation of the parameter δ¹⁵N, which must be above +2.7‱. Samples having δ¹⁸O values lower than +25.3‱ can be considered as authentic fungal chitosan. The combination of maximum degradation temperatures (obtained using TGA) and peak areas of Amide I and NH₂/Amide II (obtained using FTIR) also allows the discrimination between the two origins of the polysaccharide. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) based on TGA, FTIR and SIR data successfully distributed the tested samples into informative clusters. Therefore, we present the technologies described as part of a robust analytical strategy for the correct identification of chitosan samples from crustaceans or fungi.

Chitosan-based drug delivery systems for skin atopic dermatitis: recent advancements and patent trends

Atopic dermatitis (AD) is a complex, relapsing inflammatory skin disease with a considerable social and economic burden globally. AD is primarily characterized by its chronic pattern and it can have important modifications in the quality of life of the patients and caretakers. One of the fastest-growing topics in translational medicine today is the exploration of new or repurposed functional biomaterials into drug delivery therapeutic applications. This area has gained a considerable amount of research which produced many innovative drug delivery systems for inflammatory skin diseases like AD. Chitosan, a polysaccharide, has attracted attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine, and has been considered a promising candidate for AD treatment due to its antimicrobial, antioxidative, and inflammatory response modulation properties. The current pharmacological treatment for AD involves prescribing topical corticosteroid and calcineurin inhibitors. However, the adverse reactions associated with the long-term usage of these drugs such as itching, burning, or stinging sensation are also well documented. Innovative formulation strategies, including the use of micro- and nanoparticulate systems, biopolymer hydrogel composites, nanofibers, and textile fabrication are being extensively researched with an aim to produce a safe and effective delivery system for AD treatment with minimal side effects. This review outlines the recent development of various chitosan-based drug delivery systems for the treatment of AD published in the past 10 years (2012-2022). These chitosan-based delivery systems include hydrogels, films, micro-, and nanoparticulate systems as well as chitosan textile. The global patent trends on chitosan-based formulations for the AD are also discussed.

Saccharomyces Cerevisiae as an Untapped Source of Fungal Chitosan for Antimicrobial Action

Despite being widely available, Saccharomyces cerevisiae has not been widely explored for direct extraction of chitosan biopolymer for antimicrobial applications. In our study, S. cerevisiae from Baker's yeast and Aspergillus niger from moldy onion extracts are studied as alternative sources of chitosan; and S cerevisiae chitosan tested for antimicrobial efficacy. The properties of S. cerevisiae chitosan are compared with moldy onion chitosan and shrimp chitosan extracted from shrimp shells. Chitosan extracted from S. cerevisiae is tested for antimicrobial efficacy against Staphylococcus Aureus. The maximum yields of fungal chitosan are 20.85 ± 0.35 mg/g dry S. cerevisiae biomass at 4th day using a culture broth containing sodium acetate, and 16.15 ± 0.95 mg/g dry A. niger biomass at 12th day. The degree of deacetylation (DD%) of the extracted fungal chitosan samples from S. cerevisiae and A. niger is found to be 63.4%, and 61.2% respectively, using Fourier Transform Infrared Spectroscopy. At a concentration of 2 g/L, S. cerevisiae chitosan shows the maximum inhibition zone diameter of 15.48 ± 0.07 mm. Baker's yeast S cerevisiae biomass and A. niger from moldy onions has not been previously explored as a source of extractible fungal chitosan. This study gives insight that S. cerevisiae and A. niger from agricultural or industrial wastes could be a potential biomass source for production of the chitosan biopolymer. The S. cerevisiae chitosan displayed effective antimicrobial properties against S aureus, indicating the viablitiy of S cerevisae as a resource for extraction of high-quality chitosan.

An approach to change the basic polymer composition of the milled Fomes fomentarius fruiting bodies

Background

Chitin and its derivative chitosan are readily exploited, especially in food, cosmetic, pharmaceutical, biomedical, chemical, and textile industries. The biopolymers are currently recovered from the crustacean shells after purification from the large amount of proteins and minerals. The key problems are centered around a lot of chemical waste and allergenic potential of the heat-stable remaining proteins. Fungi can be considered as an alternative eco-friendlier source of the chitin and chitosan due to the lower level of inorganic materials and absence of the allergenic proteins.

Results

The work presents a new chemical assay to change the composition of the milled Fomes fomentarius fruiting bodies. A gradual 13-fold increase of the chitin amount accompanied by 14-fold decrease of the glucan content was obtained after repetitive alkali-acidic treatment. Raw material contained mainly chitin with 30% degree of deacetylation. After the first and second alkali treatment, the polymer was defined as chitosan with comparable amounts of N-acetyl-d-glucosamine and d-glucosamine units. The last treated samples showed an increase of the chitin amount to 80%, along with typical for the natural tinder fibers degree of deacetylation and three-dimensional fibrous hollow structure.

Conclusions

A new approach allowed a gradual enrichment of the pulverized Fomes fomentarius fruiting bodies with chitin or chitosan, depending on the extraction conditions. High stability and fibrous structure of the fungal cell walls with a drastically increased chitin ratio let us suggest a possibility of the targeted production of the chitin-enriched fungal material biotechnologically under eco-friendly conditions.

Nanomaterials Derived from Fungal Sources-Is It the New Hype?

Greener alternatives to synthetic polymers are constantly being investigated and sought after. Chitin is a natural polysaccharide that gives structural support to crustacean shells, insect exoskeletons, and fungal cell walls. Like cellulose, chitin resides in nanosized structural elements that can be isolated as nanofibers and nanocrystals by various top-down approaches, targeted at disintegrating the native construct. Chitin has, however, been largely overshadowed by cellulose when discussing the materials aspects of the nanosized components. This Perspective presents a thorough overview of chitin-related materials research with an analytical focus on nanocomposites and nanopapers. The red line running through the text emphasizes the use of fungal chitin that represents several advantages over the more popular crustacean sources, particularly in terms of nanofiber isolation from the native matrix. In addition, many β-glucans are preserved in chitin upon its isolation from the fungal matrix, enabling new horizons for various engineering solutions.

Evaluation of quantity and quality of chitosan produce from Rhizopus oryzae by utilizing food product processing waste whey and molasses

Low cost whey salt medium (WSM) and molasses salt medium (MSM) have been constructed utilizing food processing byproduct whey and molasses for the production of bio-polysaccharide chitosan from Rhizopus oryzae and subsequently comprehensive physico-chemical characterization of the fungal chitosan has been carried out using various analytical tools to apprehend its biochemical utility. Same has been repeated with chitosan from conventional potato dextrose broth (PDB) for comparison purpose. The yields of chitosan in three different media were 0.62 (WSM), 0.39 (MSM) and 0.63 (PDB) g/L respectively. Molecular weights of the chitosans were in the range of 100-300 kDa. WSM-chitosan and MSM-chitosan were less polydispersed, possessed more hydrated polymorph and loose crystal packing than PDB-chitosan. This indicate that WSM-chitosan and MSM-chitosan are highly exposed to the external reagent hence more reactive to the external reagents with compare to PDB-chitosan. Literature suggest isolated chitosans are useful for specific drug delivery applications.

Schistocerca piceifrons piceifrons (Orthoptera: Acrididae) as a Source of Compounds of Biotechnological and Nutritional Interest

The Central American locust, Schistocerca piceifrons piceifrons (Walker) is a major agricultural pest in Mexico and Central America. Control measures against this pest have generated much environmental damage and substantial financial costs because chemical insecticides are used. Yet various Orthoptera species also appear to be a potential source of nutrients and a source of bioactive metabolites. Here, we studied the presence of secondary metabolites in the adult stage of S. p. piceifrons by applying different colorimetric techniques. Adults were collected from the southern region of Tamaulipas, Mexico, during September-December 2017. These samples were subjected to sequential processes of eviscerating, drying, pulverizing, extracting, and detecting of metabolites. Extractions were carried out in water, 50% ethanol, and absolute ethanol. The presence of phenolic compounds, alkaloids, tannins, saponins, flavonoids, and quantity of antioxidants against the DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ABTS (2, 2'-azino-bis, 3-ethylbenzothiazoline-6-sulfonic acid) radicals were determined and reported. Proximate analysis showed that S. p. piceifrons has a high protein content (80.26%), low fat content (6.21%), and fiber content (12.56%) similar to other Orthoptera species. Chitin and chitosan contents of S. p. piceifrons were 11.88 and 9.11%, respectively; the recovery percentage of chitosan from chitin was 76.71%. Among the Orthoptera, the protein content of this pest is among the highest while its contents of chitin and chitosan are similar to those of other insect species (e.g., Bombix mori Linnaeus [Lepidoptera: Bombycidae]). Our results suggest this pest species is a potential source of bioactive compounds of biotechnological interest for use by pharmaceutical and food industries.

Extraction and characterization of chitin from sea snail Conus inscriptus (Reeve, 1843)

The chitin was extracted from C. inscriptus and the structure was elucidated. The yield of the C. inscriptus shell chitin was 21.65% on dry weight basis. The ash and moisture content of the chitin was 1.2 and 6.50%. The result of the molecular analysis of the chitin revealed low molecular weight (25 kDa). The crystalline structure (XRD), functional group (FT-IR), elemental analysis (EDAX), surface morphology (SEM) and thermal stability (TG/DTA) results confirmed conus chitin was in α-crystalline form. The crystalline index value (CrI) of the conus chitin was 82.13%. The FT-IR analysis of the conus chitin displayed two bands at around 1730 and 1628 cm^-1. SEM investigation of the commercial chitin and C. inscriptus chitin exposed that it was composed of nanopore and nanofibre structures. Further, the thermal stability of the conus chitin was close to the thermal stability of the commercial chitin. The results show that processing of C. inscriptus shell can lead to a high quality chitin, useful for a broad range of applications.

Bioinspired Poly(vinylidene fluoride) Membranes with Directional Release of Therapeutic Essential Oils

Here, the morphology of polypore fungi has inspired the fabrication of poly(vinylidene fluoride) (PVDF) membranes with dual porosity by nonsolvent-induced phase separation (NIPS). The fruiting body of such microorganisms is constituted of two distinct regions, finger- and sponge-like structures, which have been successfully mimicked by controlling the coagulation bath temperature during the NIPS process. The use of water at 10 °C as coagulant resulted in membranes with the highest finger-like/sponge-like ratio (53% of the total membrane thickness), while water at 90 °C allowed the formation of macrovoid-free membranes. The microchannels and the asymmetric porosity were used to enhance the oil sorption capacity of the PVDF membranes and to achieve directional release of therapeutic essential oils. These PVDF membranes with easily tuned asymmetric channel-like porosity and controlled pore size are ideal candidates for drug delivery applications.

Extraction and physicochemical characterization of chitin and chitosan from Zophobas morio larvae in varying sodium hydroxide concentration

Large amount of sodium hydroxide (NaOH) is consumed to remove the protein content in chitin biomass during deproteinization. However, excessive NaOH concentration used might lead to the reduction of cost effectiveness during chitin extraction. Hence, the present study aimed to extract and evaluate the physicochemical properties of chitin and chitosan isolated from superworm (Zophobas morio) larvae using 0.5M-2.0M of NaOH. The extracted chitin and chitosan were subjected to Fourier Transform Infrared Spectroscopy (FT-IR), elemental analysis, Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD). The 0.5M NaOH treatment resulted in the highest yield of chitin (5.43%), but produced the lowest yield (65.84%) of chitosan. The extracted chitin samples had relatively high degree of acetylation (DA) (82.39%-101.39%). Both chitin and chitosan showed smooth surface with tiny pores. The extracted chitin samples were confirmed as α-chitin based on the FT-IR and TGA. The chitin samples were amorphous with low degree of crystallinity. From TGA, the Chitosan 3 extracted was partially deacetylated. Both DPPH radical scavenging and ferric-chelating assay showed positive correlation with DD of chitosan isolates. However, the chitosan isolates were not fully dissolved, resulting in lower radical scavenging and ferric-chelating ability compared to commercial chitosan.

Recent advances in polysaccharide bio-based flocculants

Natural polysaccharides, derived from biomass feedstocks, marine resources, and microorganisms, have been attracting considerable attention as benign and environmentally friendly substitutes for synthetic polymeric products. Besides many other applications, these biopolymers are rapidly emerging as viable alternatives to harmful synthetic flocculating agents for the removal of contaminants from water and wastewater. In recent years, a great deal of effort has been devoted to improve the production and performance of polysaccharide bio-based flocculants. In this review, current trends in preparation and chemical modification of polysaccharide bio-based flocculants and their flocculation performance are discussed. Aspects including mechanisms of flocculation, biosynthesis, classification, purification and characterization, chemical modification, the effect of physicochemical factors on flocculating activity, and recent applications of polysaccharide bio-based flocculants are summarized and presented.

Cisplatin-Mediated Formation of Polyampholytic Chitosan Nanoparticles with Attenuated Viscosity and pH-Sensitive Drug Release

Chitosan is a biocompatible natural polysaccharide, which has been employed as a polymeric scaffold for versatile, systemic delivery platforms and for locally injectable gels with temperature-sensitive viscosity modulation. Despite the extensive investigation on the chemical modification strategies, however, most of the chitosan-based delivery platforms have been focused on the encapsulation of hydrophobic drugs, which can be simply adsorbed on the chitosan scaffolds by hydrophobic interaction via the postparticle-formation drug-loading process. Herein, we present the facile formation of a cisplatin-coordinated chitosan nanoplatform by exploiting the divalent metal (Pt^II)-mediated conformational changes of chitosan chains, which allows for the simultaneous drug-loading and nanoparticle formation. To this end, the native chitosan has been chemically modified with short polyethylene glycol and malonic acid as a colloidal stabilizer and a bidentate chelating ligand for Pt^II coordination, respectively. The resulting Pt^II-modified polyampholytic chitosan (Pt^II-MPC) has been self-associated in aqueous media by hydrophobic segregation into a compact nanostructure, which exhibited an attenuated viscosity and pH-sensitive release of Pt^II compounds. Once the cationic drug molecules have been released under mild acidic conditions, the neutralized Pt^II-free MPC undergoes interchain flocculation near the isoelectric point because of the polyampholytic property, possibly allowing for the facilitated endosomal escape during the cellular endocytosis by the known membrane perturbation property of chitosan.

Studies of chitosan/pectin complexes exposed to UV radiation

Chitosan and pectin form complexes owing to electrostatic interactions between positively charged amino groups in chitosan and negatively charged carboxylate groups in pectin, which was confirmed by ATR-FTIR spectroscopy and contact angle measurements. Moreover, the formation of these complexes might be associated with the loss of the biopolymers ordering, which resulted in higher surface roughness and lower thermal stability of the complexes in comparison to those of homopolymers. UV rays, used as a sterilizing agent, caused a moderate increase in the surface polarity of the complexes. Roughness parameters of these samples changed irregularly after irradiation, and their thermal stability was slightly affected by UV rays. The results indicated that the complexes studied appeared to present resistance to UV action higher than homopolymers, which is a desirable property in medical or pharmaceutical applications.

Current Status and New Perspectives on Chitin and Chitosan as Functional Biopolymers

The natural biopolymer chitin and its deacetylated product chitosan are found abundantly in nature as structural building blocks and are used in all sectors of human activities like materials science, nutrition, health care, and energy. Far from being fully recognized, these polymers are able to open opportunities for completely novel applications due to their exceptional properties which an economic value is intrinsically entrapped. On a commercial scale, chitosan is mainly obtained from crustacean shells rather than from the fungal and insect sources. Significant efforts have been devoted to commercialize chitosan extracted from fungal and insect sources to completely replace crustacean-derived chitosan. However, the traditional chitin extraction processes are laden with many disadvantages. The present review discusses the potential bioextraction of chitosan from fungal, insect, and crustacean as well as its superior physico-chemical properties. The different aspects of fungal, insects, and crustacean chitosan extraction methods and various parameters having an effect on the yield of chitin and chitosan are discussed in detail. In addition, this review also deals with essential attributes of chitosan for high value-added applications in different fields and highlighted new perspectives on the production of chitin and deacetylated chitosan from different sources with the concomitant reduction of the environmental impact.

Physicochemical and Antibacterial Properties of Chitosan Extracted from Waste Shrimp Shells

This research aims to study the production of chitosan from shrimp shell (Litopenaeus vannamei) of waste origin using two chemical methodologies involving demineralization, deproteinization, and the degree of deacetylation. The evaluation of the quality of chitosan from waste shrimp shells includes parameters for the yield, physical chemistry characteristics by infrared spectroscopy (FT-IR), the degree of deacetylation, and antibacterial activity. The results showed (by Method 1) extraction yields for chitin of 33% and for chitosan of 49% and a 76% degree of deacetylation. Chitosan obtained by Method 2 was more efficient: chitin (36%) and chitosan (63%), with a high degree of deacetylation (81.7%). The antibacterial activity was tested against Gram-negative bacteria (Stenotrophomonas maltophilia and Enterobacter cloacae) and Gram-positive Bacillus subtilis and the Minimum Inhibitory Concentrations (MIC) and the Minimum Bactericidal Concentration (MBC) were determined. Method 2 showed that extracted chitosan has good antimicrobial potential against Gram-positive and Gram-negative bacteria and that the process is viable.

Antifungal Effect of Chitosan as Ca(2+) Channel Blocker

The aim of this study was to investigate antifungal activity of a range of different molecular weight (MW) chitosan against Penicillium italicum. Our results demonstrate that the antifungal activity was dependent both the MW and concentration of the chitosan. Among a series of chitosan derived from the hydrolysis of high MW chitosan, the fractions containing various sizes of chitosan ranging from 3 to 15 glucosamine units named as chitooligomers-F2 (CO-F2) was found to show the highest antifungal activity against P. italicum. Furthermore, the effect of CO-F2 toward this fungus was significantly reduced in the presence of Ca(2+), whereas its effect was recovered by ethylenediaminetetraacetic acid, suggesting that the CO-F2 acts via disruption of Ca(2+) gradient required for survival of the fungus. Our results suggest that CO-F2 may serve as potential compounds to develop alternatives to synthetic fungicides for the control of the postharvest diseases.

Chitin dipentanoate as the new technologically usable biomaterial

In this article, the synthesis of novel biopolymer, chitin dipentanoate (Di-O-Valeryl Chitin, DVCH) has been described. DVCH is a chitin derivative esterified with two valeryl groups at positions 3 and 6 of the N-acetylglucosamine units and it is soluble in common organic solvents like ethanol, methanol, acetone, dichloromethane, 1,2-dichloroethane, N,N-dimethylmethanamide, N,N-dimethylacetamide and ethyl acetate. Highly efficient synthesis (degree of esterification close to 2) of DVCH was achieved by employing a huge excess of valeric anhydride used as both the acylation agent and the reaction medium in the presence of perchloric acid as catalyst. Studies on the DVCH synthesis were aimed at finding optimal conditions (temperature, reaction time) to obtain DVCH with high reaction yield and desirable physicochemical properties. Biological data demonstrate that DVCH is non-cytotoxic in vitro and doesn't exert irritating or allergic effects to animal skin. Thanks to its filmogenic properties, it can be used to manufacture threads, foils, foams and non-woven materials. Moreover, DVCH can be easily processed by salt-leaching method to prepare highly porous structures exhibiting open-cell architecture, that can be further employed in wound dressing therapies and scaffolds for tissue engineering.