Degree Of Acetylation Research Articles

Orally administrated chitosan microspheres bind Helicobacter pylori and decrease gastric infection in mice

Persistent Helicobacter pylori (H. pylori) infection is related to 90% of gastric cancers. With bacterial resistance rising and treatment inefficiency affecting 15% of the patients, alternative treatments urge. Chitosan microspheres (ChMics) have been proposed as an H. pylori-binding system. This work evaluates ChMics biocompatibility, mucopenetration and capacity to treat H. pylori infection in mice after oral administration. ChMics of different size (XL, ∼120 µm and XS, ∼40 µm) and degree of acetylation (6% and 16%) were developed and revealed to be able to adhere both human and mouse-adapted H. pylori strains without cytotoxicity towards human gastric cells. Ex vivo studies showed that smaller (XS) microspheres penetrate further within the gastric foveolae, suggesting their ability to reach deeply adherent bacteria. In vivo assays showed 88% reduction of infection when H. pylori-infected mice (C57BL/6) were treated with more mucoadhesive XL6 and XS6 ChMics. Overall, ChMics clearly demonstrate ability to reduce H. pylori gastric infection in mice, with chitosan degree of acetylation being a dominant factor over microspheres’ size on H. pylori removal efficiency. These results evidence the strong potential of this strategy as an antibiotic-free approach to fight H. pylori infection, where microspheres are orally administered, bind H. pylori in the stomach, and remove them through the gastrointestinal tract. Statement of SignificanceApproximately 90% of gastric cancers are caused by the carcinogenic agent Helicobacter pylori, which infects >50% of the world population. Bacterial resistance, reduced antibiotic bioavailability, and the intricate distribution of bacteria in mucus and within gastric foveolae hamper the success of most strategies to fight H. pylori. We demonstrate that an antibiotic-free therapy based on bare chitosan microspheres that bind and remove H. pylori from stomach can achieve 88% reduction of infection from H. pylori-infected mice. Changing size and mucoadhesive properties, microspheres can reach different areas of gastric mucosa: smaller and less mucoadhesive can penetrate deeper into the foveolae. This promising, simple and inexpensive strategy paves the way for a faster bench-to-bedside transition, therefore holding great potential for clinical application.

Oleuropein Improved Post Cerebral Stroke Cognitive Function by Promoting Histone Acetylation and Phosphorylation of cAMP Response Element-Binding Protein in MCAO Rats.

Background:Post-stroke cognitive impairment (PSCI) is commonest clinical disorder in which peripheral cholinergic activity is important. Oleuropein (OLP) is polyphenol is present in olive oil. Here we evaluated the effect of OLP in cognitive dysfunction rats in post cerebral stroke model.Methods:The post cerebral stroke cognitive dysfunction PSD rat model was created by occlusion of transient middle cerebral artery. The rats were divided into 6 groups named, Sham + Vehicle, Sham + OLP (50 mg/kg), PSD rats + Vehicle, PSD rats + OLP (20, 50 or 100 mg/kg). The spatial learning was assessed by Morris water maze (MWM). The expression of choline acetyltransferase (ChAT), acetylcholine (ACH), extent of histone acetylation and phosphorylation of cAMP response element-binding protein (CREB) were evaluated by Western blot assay and immunofluorescence staining.Results:Treatment of OLP at various doses showed higher number of spontaneous and rewarded alterations and lesser percentage bias compared to vehicle treated PSD rats. OLP resulted in decreased levels of ChAT and ACH, whereas the degree of histone acetylation and phosphorylation of CREB improved in dose dependent pattern.Conclusion:treatment of OLP improved PSCI via increasing the phosphorylation of CREB and histone acetylation, thus attenuating cholinergic activity.

Chitin-glucan complex – Based biopolymeric structures using biocompatible ionic liquids

This work explores the novelty of dissolving chitin-glucan complex (CGC), from two fungal strains, Komagataella pastoris (CGCP) and Aspergillus niger (CGCKZ) (KiOnutrime-CG™), using biocompatible ionic liquids (ILs). Three cholinium-based ILs were tested, choline acetate, choline propionate and choline hexanoate. Although all tested ILs resulted in the dissolution of the co-polymer at a concentration of 5 % (w/w), distinct polymeric structures, films or gels, were obtained from CGCP and CGCKZ, respectively. CGCP films were dense, flexible and elastic, with high swelling capacity (> 200 %). The IL anion alkyl chain length influenced the polymeric structures’ properties, namely, the CGCP films elongation at break and swelling degree. CGCKZ resulted in weak gels. For both polymeric structures, exposure to the ILs under the dissolution conditions caused significant changes in the co-polymers’ chemical structure, namely, reduction of their glucan moiety and reduction of the degree of acetylation, thus yielding chitosan-glucan complexes (ChGC) enriched in glucosamine (53.4 ± 0.3–60.8 ± 0.3 %).

Evaluation of Chitosan as Dressing for Skin Wound. Histopathological Experimental Study in Rabbit

Aims: To evaluate the effect of medical chitosan on wound healing. Materials and Methods: An experimental open skin wounds were made on the dorsal side of fifteen domestic rabbits. A 0.04gm of medical chitosan (degree of acetylation=90.0%) was applied. Each individual animal given intramuscular dose of kitamin hydrochloride (anesthetic and analgesic) 4mg/kg and xylazin base (anesthetic and muscle relaxant) 5mg/kg injected into rabbit’s thigh muscle. After 10-15 minutes, anesthetic integrity was checked by testing loss of ear pinch reflex. Four skin incisions were made in the dorsal site of the animal skin. Each incision was about 1cm in length. These incisions were divided into 4 groups according to placement of the material and suturing (Ca: control incision left without suturing or placement of material, Cs: control suturing of the incision only, Cha: chitosan placement only, Chs: chitosan placement and suturing of the incision). Post operatively single dose of 5mg/kg oxytetracycline antibiotic intramuscular injection was given immediately. The animals were randomly subdivided into three groups (G1, G2, G3) with five rabbits in each group and specimen obtained from each rabbit for histopathological study according to the time of sacrifices 3, 7, 14 days after surgery respectively. Biopsies took from each site of operation and examined by four histopathologists and the overall readings taken and processed statistically using SPSS version 18.0. Results: There was a significant variation in inflammatory response to chitosan when applied as powder dressing at all periods of healing. P-values were found to be 0.005, 0.022, 0.002 between four groups at 3, 7, 14 days respectively. While there was no significance in reepithelializeation between four groups at all periods of healing according to Pvalues of Friedman test. Conclusion: Medical chitosan appeared good healing accelerator by decreasing rate of inflammation and prevent infection.

Effect of chitin and chitosan hexamers on growth and photosynthetic characteristics of wheat seedlings

In this study, two homogeneous chitin and chitosan hexamers and one partially acetylated chitosan hexamer were used to investigate the degree of acetylation (DA) effects of chitooligosaccharides on the growth and photosynthesis of wheat seedlings. Both chitin and chitosan hexamers showed a significant promoting effect on the growth and photosynthesis of wheat seedlings but the positive effect depended on their DA. The homogeneous chitosan hexamers [(GlcN)6] exhibited the optimal activity compared to other samples. Seven days after (GlcN)6 treatment, the growth parameters of wheat seedlings were all significantly enhanced including fresh mass, dry mass, and length of both shoots and roots, and the contents of soluble sugar were increased by 22.8%. Additionally, (GlcN)6 could significantly promote (by 90.0%) the photosynthetic rate of wheat seedlings. Both Rubisco and fructose-1,6-bisphosphatase activity of photosynthetic carbon metabolism was also found to be significantly improved by (GlcN)6 treatment.

Multi-step purification method of water-soluble oligosaccharides produced from hardwood and softwood

Abstract Pressurized hot water pretreatment was performed on softwood (SW) and hardwood (HW) chips following the same conditions (1 h at 170 °C) in order to partly hydrolyse hemicelluloses. The complete characterization of these sugar enriched autohydrolysates (AH) being rather complex, two different purification methods were conducted. Nanofiltration (NF) 1kDa membrane and ultrafiltration (UF) 3 and 5kDa membranes were used to separate oligosaccharides (OS) from undesired compounds and for their molar mass fractionation. Granulated activated charcoal (GAC) adsorption was also used for hydrolysates detoxification. The chemical nature of OS and side charge groups vary significantly depending of the fractions obtained, e. g. xylans' chain length is positively correlated with the degree of acetylation. UF at 5kDa allows for the total separation of galactoglucomannans (GGMs) from xylans, in SW AH, however, this result was not achieved with HW. From the acid soluble lignin (ASL) removal point of view, membrane filtration from 1kDa is more efficient than activated carbon treatment concerning HW AH, on the contrary to SW AH. Regarding the lignin to OS ratio, for both species, GAC leads to a better sugar purity.

Structural features, anti-coagulant and anti-adhesive potentials of blue crab (Portunus segnis) chitosan derivatives: Study of the effects of acetylation degree and molecular weight

The present study was undertaken to establish a distinct relationship between blue crab chitosan (Cs) acetylation degree (AD) and molecular weight (Mw) and its structural features, thermal properties and bioactivity. Therefore, chitosans with different AD were prepared and Cellulase was used to produce Cs derivatives with decreasing Mw. Results clearly display a decrease of the ordered structure of Cs, with the increase of AD and the decrease of Mw. Thermal stability/degradation screening disclose a greater thermal resistance for Cs with lower AD and higher Mw. The anti-adhesive potential of Cs was, additionally, studied, as function of AD and Mw. The effectiveness of Cs in preventing biofilm adhesion was strongly influenced by its AD and Mw, with the lowest inhibition values for higher AD and lower Mw. Interestingly, the effectiveness of Cs in disrupting pre-formed biofilms increased with decreasing Mw. Moreover, Cs derivatives were found to be advantageously efficient in prolonging human blood clotting times, based on data of activated partial thromboplastin time, Quick time and thrombin time assays, typically for the intrinsic coagulation pathway. Accordingly, depending on the predicted application of Cs, either in food, biomedical and pharmaceutical industries, AD and Mw are critical traits to be inevitably reflected on.

Extraction and Physicochemical Characterization of Chitin from Cicada orni Sloughs of the South-Eastern French Mediterranean Basin.

Chitin is a structural polysaccharide of the cell walls of fungi and exoskeletons of insects and crustaceans. In this study, chitin was extracted, for the first time in our knowledge, from the Cicada orni sloughs of the south-eastern French Mediterranean basin by treatment with 1 M HCl for demineralization, 1 M NaOH for deproteinization, and 1% NaClO for decolorization. The different steps of extraction were investigated by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). Results demonstrated that the extraction process was efficiently performed and that Cicada orni sloughs of the south-eastern French Mediterranean basin have a high content of chitin (42.8%) in the α-form with a high degree of acetylation of 96% ± 3.4%. These results make Cicada orni of the south-eastern French Mediterranean basin a new and promising source of chitin. Furthermore, we showed that each step of the extraction present specific characteristics (for example FTIR and XRD spectra and, consequently, distinct absorbance peaks and values of crystallinity as well as defined values of maximum degradation temperatures identifiable by TGA analysis) that could be used to verify the effectiveness of the treatments, and could be favorably compared with other natural chitin sources.

Encapsulation of caffeine in polysaccharide oil-core nanocapsules

Nanoemulsion droplets stabilized with a polysaccharide multilayer film were used as carriers for caffeine. Multilayered shells were formed through a subsequent layer-by-layer adsorption of oppositely charged chitosan and alginate (sodium salt) onto emulsion droplets or oil-core nanocapsules at low ionic strength. The hydrophilic positively charged molecules of the drug were impregnated into the film after each alginate layer. The experimental results showed dependence of the encapsulation efficiency of caffeine on the number of the adsorbed polymer layers and on the properties of chitosan used for formation of the film (molecular weight and degree of acetylation). Despite the low encapsulation efficiency of the drug into the capsules (~ 40%) compared with other encapsulation systems, the amount loaded into the film was high enough and pharmacological doses were achieved with very small volumes of the dispersion.

Chitin from fermentative extraction of crab shells using okara as a nutrient source and comparative analysis of structural differences from chemically extracted chitin

Chitin was obtained by economic fermentative and chemical extractions from crab shell to compare the structural differences. In the fermentation, soybean curd residue (okara) and its extracted protein were used as nutrient sources in the proteinic culture medium of Bacillus pumilus. It was found that essential amino acids and minerals contained in okara-extracted protein were similar to those of commercial yeast extract leading to chitin with similar properties. A comparison of biologically and chemically extracted chitins showed the degree of acetylation was ca. 71 %, but their crystallinities were different at 73 % and 86 %, respectively, the result of differences in intermolecular hydrogen bonding and crystallite size. A high degree of deproteinization of chitin was found after fermentation, while decalcification occurred to a small extent. Post-fermentation treatment with acetic acid enhanced the decalcification to nearly 100 %. The purified chitin had a weight average molecular weight of 4−10 × 106g/mol, depending on the extraction condition.

Genipin cross-linked chitosan for signal enhancement in the colorimetric detection of aflatoxin B1 on 3MM chromatography paper

Detection of mycotoxins by conventional methods such as ELISA or LC-MS can be expensive and time-consuming. Therefore, paper-based biosensors can be effectively used for on-site analysis, due to their low cost and easy detection procedures. Nevertheless, even when the application of colorimetric methods on paper enhance the simplicity and affordability of multiple determinations, the signal intensity and final readout can be affected by a limited color uniformity. In this work, Ellman’s method for the quantification of aflatoxin B1 was utilized as a model colorimetric assay on paper, in which the test zones were modified with chitosan-immobilized enzyme (AChE). A comparison of the cross-linking effect of genipin on two chitosans of varying molar mass and degree of acetylation, exhibited a greater signal enhancement from the sample with a higher degree of acetylation and molecular weight.

Chitin, Chitosan, and Submicron-Sized Chitosan Particles Prepared from Scylla serrata Shells

Extraction of chitin from mud crab (Scylla serrata) shells, involving demineralization and deproteinization, and deacetylation of the extracted chitin to form chitosan were investigated. The mud crab chitin and chitosan were obtained with a good yield (16.8% and 84.7% based on dried weight basis). The physicochemical properties, functional groups, molecular weight, and degree of acetylation of the chitin and chitosan were characterized. The surface morphology, the orientation arrangement of polysaccharide strands, and crystallinity of the chitin and chitosan prepared from the mud crab shells were investigated. SEM, FTIR, and XRD analyses demonstrated that the chitin consists of micron-sized fibrils, belonging to α from with the crystallinity of 60.1%. The chitosan has a viscosity-average molecular weight of 6.83 kDa with the degree of acetylation being 9.6% and the crystallinity of 73.8%. The chitosan was successfully fabricated into submicron-sized particles using top-down ionotropic gelation, microwave, and microemulsion methods, employing sodium tripolyphosphate, potassium persulfate, and glutaraldehyde as reagents, respectively. Overall, the results indicated that the preparation of chitin, chitosan, and submicron-sized chitosan particles from mud crab shells could open the opportunity for the value-added seafood waste to be utilized in a wide range of practical applications.

Effect of the degree of acetylation on the physicochemical properties of α-chitin nanofibers

The effective utilization of abundant α-chitin resources for materials engineering applications requires methods for controlling the physicochemical properties of α-chitin nanofiber (NF) dispersions. Herein, the relationship between the degree of acetylation (DA) of α-chitin and the physicochemical properties of α-chitin nanofibers (α-ChNFs) was investigated. α-Chitin with different DAs was prepared by varying the deacetylation treatment time. These α-chitin samples were disintegrated into NFs using wet pulverization. The average width of the α-ChNFs decreased with decreasing DA. Furthermore, the transmittance and viscosity of the α-ChNF dispersions increased with decreasing DA. We successfully developed a simple model for estimating the average width of α-ChNFs with different DAs. These results indicate that the DA is an effective parameter for defining and controlling the physicochemical properties of α-ChNFs.

Low Temperature Dissolution of Yeast Chitin-Glucan Complex and Characterization of the Regenerated Polymer.

Chitin-glucan complex (CGC) is a copolymer composed of chitin and glucan moieties extracted from the cell-walls of several yeasts and fungi. Despite its proven valuable properties, that include antibacterial, antioxidant and anticancer activity, the utilization of CGC in many applications is hindered by its insolubility in water and most solvents. In this study, NaOH/urea solvent systems were used for the first time for solubilization of CGC extracted from the yeast Komagataella pastoris. Different NaOH/urea ratios (6:8, 8:4 and 11:4 (w/w), respectively) were used to obtain aqueous solutions using a freeze/thaw procedure. There was an overall solubilization of 63–68%, with the highest solubilization rate obtained for the highest tested urea concentration (8 wt%). The regenerated polymer, obtained by dialysis of the alkali solutions followed by lyophilization, formed porous macrostructures characterized by a chemical composition similar to that of the starting co-polymer, although the acetylation degree decreased from 61.3% to 33.9–50.6%, indicating that chitin was converted into chitosan, yielding chitosan-glucan complex (ChGC). Consistent with this, there was a reduction of the crystallinity index and thermal degradation temperature. Given these results, this study reports a simple and green procedure to solubilize CGC and obtain aqueous ChGC solutions that can be processed as novel biomaterials.

Developing a biopolymeric chitosan supported Schiff-base and Cu(II), Ni(II) and Zn(II) complexes and biological evaluation as pro-drug

Chitosan derivatives are widely used as key classes of medicinal compounds owing to their non- toxic and biodegradable properties. So, in this work, to enhance chitosan biological activities, a new synthesis of a series of Schiff base and its metals complexes (Cu(II), Ni(II) and Zn(II)) of chitosan (CS) was prepared. Moreover, their physicochemical properties were characterized by IR, UV–Vis, SEM, melting point, thermo gravimetric analysis (TGA), X-ray diffraction (XRD), elemental analysis and 1H NMR techniques. Elemental analysis data confirmed the formation of chitosan-Schiff base as well as the coordination reaction with metals ions by increasing the carbon content caused by substitution. By elemental analysis, the degrees of acetylation (DA), deacetylation (DD) and substitution (DS) were acquired 23, 77.63 and 57.90%, respectively. Additionally, the 1H NMR spectroscopy was used for the determination of degree of deacetylation (DD) and Substitution (DS) of chitosan ranging from 87.5 and 85%, respectively. The presence of a new low-field signal at 10.23 ppm in the 1H NMR spectra confirmed the imine proton of Schiff base. The cytotoxicity of Chitosan, Chitosan-Schiff base and its metals complexes was tested against K562 chronic myelogenous leukemia (CML) and MG-63 (osteosarcoma cancer) cell lines by the MTT assay. The results suggested that the anticancer activity of Schiff base and their complexes was much better than that of pure CS against cancer MG63 cell line. Finally, through flow cytometry, we demonstrated that all compounds were efficient in inducing apoptosis effect in K562 and MG63 cell lines except Schiff base- chitosan in K562 cell lines.

Crystallinity reduction and enhancement in the chemical reactivity of cellulose by non-dissolving pre-treatment with tetrabutylphosphonium acetate

Herein, we demonstrate the activation of commercial chemical cellulose pulps towards chemical modification by a pre-treatment step with tetrabutylphosphonium acetate ([P4444][OAc]). A heterogeneous (non-dissolving) pre-treatment was applied allowing for a significant reduction in crystallinity, without concomitant formation of the thermodynamically stable cellulose II. An increase in chemical reactivity was demonstrated using two model reactions; (1) acetylation (organic swelling conditions), where high degrees of substitution (DS) were obtained without the need for a catalyst, and (2) 4-acetamido-TEMPO oxidation (aqueous swelling conditions), where significant degrees of oxidation (DO) were obtained, beyond those for the untreated pulps. In both tests a notable improvement in cellulose reactivity was observed. Regioselectivity of acetylation was assessed using 2D NMR for one low and one high DS sample. The low DS showed a small degree of acetylation of the 6-OH, whereas, the high DS from the pre-treated sample showed mainly mixtures of triacetate and diacetates. Important mechanistic information is attained for future development of aqueous and organic-based reactions involving this ionic liquid pre-treatment.

Thermoplastic "All-Cellulose" Composites with Covalently Attached Carbonized Cellulose.

Thermoplastic “all-cellulose” composites were synthesized by covalent functionalization of cellulose acetate (CA) with oxidized carbonized cellulose (OCC). The OCC were manufactured via microwave-assisted hydrothermal carbonization (HTC) of cellulose followed by oxidation and dialysis. The OCC were of micrometer-size, had plane morphology and contained a variety of oxygen functionalities, enabling transformation into acyl chlorinated OCC under moderate reaction conditions. The synthesis of OCC-modified CA composites and neat CA were performed in the recyclable ionic liquid 1-allyl-3-methylimidazolium chloride. The degree of acetylation and amount of OCC were varied to establish their influence on thermal and physical properties of the composites. The OCC-modified CA composites displayed a notably enhanced film-forming ability, which led to improved optical and mechanical properties compared to neat CA. In addition, it was shown that OCC-modified CA composites can be synthesized from waste products, such as paper tissues. The OCC-modification was demonstrated to be a promising route to transparent and strong thermoplastic “all-cellulose” composites with moderate flexibility.

Enhancing the functional properties of acetylated hemicellulose films for active food packaging using acetylated nanocellulose reinforcement and polycaprolactone coating

Abstract Acetylated hemicellulose (AH)-nanocellulose (ACNC) films coated with polycaprolactone (PCL) films, were evaluated as active packaging for aqueous, alcoholic, fatty and acidic food. The effects of nanocellulose loading (0–50 %), degree of acetylation (DS) (0–2.34) and polycaprolactone coating (0.3 g/mL) on hydrophobicity and solubility of AH films in food simulants, were investigated. In addition, AH-CNC/PCL films were doped with polyphenols and their antioxidant release (temperature 5 °C–40 °C, time - 48 h) into food simulants was evaluated experimentally and by modelling (Migratest software). Increasing ACNC DS and loading, combined with a PCL coating increased films’ hydrophobicity (24.59° to 82.48°) and reduced film solubility in all the simulants (∼82.8 %). The release of polyphenols by the films was highest and best predicted using Migratest software for the fatty food simulant. Therefore, these films can be used as active packaging for fatty foods. Furthermore, Migratest modelling can be used to predict film performance during film design.

Production of prebiotic chitooligosaccharide and its nano/microencapsulation for the production of functional yoghurt

Production and potential application of chitooligosaccharide is reported in this study. Chitooligosaccharide was produced by enzymatic hydrolysis of chitosan using Bacillus cereus chitosanase. The chitooligosaccharide was characterized, and its prebiotic activity together with the antioxidant activity were evaluated and compared to marketed standard and chitosan. Additionally, its stability in yoghurt was monitored. The produced chitooligosaccharide was water soluble with molecular weight of 2.005 kDa and higher degree of acetylation. Bioactivity results cleared the chitooligosaccharide has potent prebiotic plus antioxidant activity with poor stability in yoghurt. Subsequently, encapsulation of chitooligosaccharide into nanoparticles and microparticle were assessed to enhance its stability. Our results indicated that nanoparticles with size 100 nm maintained 96.83 + 1.2 % of chitooligosaccharide in yoghurt during shelf life compared to 45.09 ± 2.5 % for microparticle (850 μm). Finally, the sensory evaluation favored the yoghurt containing chitooligosaccharide nanoparticles over free chitooligosaccharide or chitooligosaccharide microparticle, which suggest nanoparticles as potential formula to boost the chitooligosaccharide stability in yoghurt.

Enzymatic Modification of Native Chitin and Conversion to Specialty Chemical Products.

Chitin is one of the most abundant biomolecules on earth, occurring in crustacean shells and cell walls of fungi. While the polysaccharide is threatening to pollute coastal ecosystems in the form of accumulating shell-waste, it has the potential to be converted into highly profitable derivatives with applications in medicine, biotechnology, and wastewater treatment, among others. Traditionally this is still mostly done by the employment of aggressive chemicals, yielding low quality while producing toxic by-products. In the last decades, the enzymatic conversion of chitin has been on the rise, albeit still not on the same level of cost-effectiveness compared to the traditional methods due to its multi-step character. Another severe drawback of the biotechnological approach is the highly ordered structure of chitin, which renders it nigh impossible for most glycosidic hydrolases to act upon. So far, only the Auxiliary Activity 10 family (AA10), including lytic polysaccharide monooxygenases (LPMOs), is known to hydrolyse native recalcitrant chitin, which spares the expensive first step of chemical or mechanical pre-treatment to enlarge the substrate surface. The main advantages of enzymatic conversion of chitin over conventional chemical methods are the biocompability and, more strikingly, the higher product specificity, product quality, and yield of the process. Products with a higher Mw due to no unspecific depolymerisation besides an exactly defined degree and pattern of acetylation can be yielded. This provides a new toolset of thousands of new chitin and chitosan derivatives, as the physio-chemical properties can be modified according to the desired application. This review aims to provide an overview of the biotechnological tools currently at hand, as well as challenges and crucial steps to achieve the long-term goal of enzymatic conversion of native chitin into specialty chemical products.