A new method for the quantification of chitin and chitosan in edible mushrooms

Along with β-glucans, chitin is the dominant component of the fungal cell wall. Chitosan, the deacetylated form of chitin, has found quite a number of biomedical and biotechnological applications recently. Mushroom chitin could be an important source for chitosan production. A direct determination of chitin and chitosan in mushrooms is of expedient interest. In this paper, a new method for the quantification of chitin and chitosan is described. This method is based on the specific reaction between polyiodide anions and chitosan and on measuring the optical density of the insoluble polyiodide–chitosan complex. After deacetylation, chitin can also be quantified. The specificity of the reaction is used to quantify the polymers in the presence of complex matrices. With this new spot assay, the chitin content of mycelia and fruiting bodies from several basidiomycetes and an ascomycete were analysed. The presented method could also be used for the determination in other samples as well. The chitin content of the analysed species varies between 0.4 and 9.8 g chitin per 100 g of dry mass. Chitosan could not be detected in our mushroom samples, indicating that the glucosamine units are mostly acetylated.     

Implications of molecular diversity of chitin and its derivatives

Chitin is a long unbranched polysaccharide, made up of β-1,4-linked N-acetylglucosamine which forms crystalline fiber-like structure. It is present in the fungal cell walls, insect and crustacean cuticles, nematode eggshells, and protozoa cyst. We provide a critical appraisal on the chemical modifications of chitin and its derivatives in the context of their improved efficacy in medical applications without any side effect. Recent advancement in nanobiotechnology has helped to synthesize several chitin derivatives having significant biological applications. Here, we discuss the molecular diversity of chitin and its applications in enzyme immobilization, wound healing, packaging material, controlled drug release, biomedical imaging, gene therapy, agriculture, biosensor, and cosmetics. Also, we highlighted chitin and its derivatives as an antioxidant, antimicrobial agent, anticoagulant material, food additive, and hypocholesterolemic agent. We envisage that chitin and chitosan-based nanomaterials with their potential applications would augment nanobiotechnology and biomedical industries.

     

Chitin deacetylase product inhibition

Chitin deacetylase is the only known enzyme catalyzing the hydrolysis of the acetamino linkage in the N-acetylglucosamine units of chitin and chitosan. This reaction can play an important role in enzymatic production of chitosan from chitin, or in enzymatic modification of chitosan, which has applications in medicine, pharmacy or plant protection. It was previously shown that acetic acid, a product of the deacetylation process, may act as an inhibitor of chitin deacetylase. Here we show the mechanism of inhibition of chitin deacetylase isolated from Absidia orchidis vel coerulea by acetic acid released during the deacetylation process. The process follows competitive inhibition with respect to acetic acid with an inhibition constant of K(i) = 0.286 mmol/L. These results will help to find the optimal system to carry out the enzymatic deacetylation process for industrial applications.     

Bacterial chitinases: properties and potential

Chitin is among the most abundant biomass present on Earth. Chitinase plays an important role in the decomposition of chitin and potentially in the utilization of chitin as a renewable resource. During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years due to their broad applications in medical, agricultural, and industrial applications, including antibacterial, antifungal, hypocholesterolemic, and antihypertensive activity, and as a food quality enhancer. Microorganisms, particularly bacteria, form one of the major sources of chitinase. In this article, we have reviewed some of the chitinases produced by bacterial systems that have gained worldwide research interest for their diverse properties and potential industrial uses.     

Bacterial Chitinases: Properties and Potential

ABSTRACT

Chitin is among the most abundant biomass present on Earth. Chitinase plays an important role in the decomposition of chitin and potentially in the utilization of chitin as a renewable resource. During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years due to their broad applications in medical, agricultural, and industrial applications, including antibacterial, antifungal, hypocholesterolemic, and antihypertensive activity, and as a food quality enhancer. Microorganisms, particularly bacteria, form one of the major sources of chitinase. In this article, we have reviewed some of the chitinases produced by bacterial systems that have gained worldwide research interest for their diverse properties and potential industrial uses.     

Sulfated chitin and chitosan as novel biomaterials

Chitin and chitosan are known to be natural polymers and they are non-toxic, biodegradable and biocompatible. Chemical modification of chitin and chitosan with sulfate to generate new bifunctional materials is of interest because the modification would not change the fundamental skeleton of chitin and chitosan, would keep the original physicochemical and biochemical properties and finally would bring new or improved properties. The sulfated chitin and chitosan have a variety of applications, such as, adsorbing metal ions, drug delivery systems, blood compatibility, and antibacterial field. The purpose of this review is to take a closer look about the different synthetic methods and potential applications of sulfated chitin and chitosan. Based on current research and existing products, some new and futuristic approaches in this context area are discussed in detail. From the studies reviewed, we concluded that sulfated chitin and chitosan are promising materials for biomedical applications.     

Preparative methods of phosphorylated chitin and chitosan--an overview

Biomaterials such as chitin, chitosan and their derivatives have a significant and rapid development in recent years. Chitin and chitosan have become cynosure of all party because of an unusual combination of biological activities plus mechanical and physical properties. However, the applications of chitin and chitosan are limited due to its insolubility in most of the solvents. The chemical modification of chitin and chitosan are keen interest because of these modifications would not change the fundamental skeleton of chitin and chitosan but would keep the original physicochemical and biochemical properties. They would also bring new or improved properties. The chemical modification of chitin and chitosan by phosphorylation is expected to be biocompatible and is able to promote tissue regeneration. In view of rapidly growing interest in chitin and chitosan and their chemical modified derivatives, we are here focusing the recent developments on preparation of phosphorylated chitin and chitosan in different methods.     

CHITIN — A promising biomaterial for tissue engineering and stem cell technologies

Chitin, after cellulose, is the second most abundant natural polymer. With a 200-year history of scientific research, chitin is beginning to see fruitful application in the fields of stem cell and tissue engineering. To date, however, research in chitin as a biomaterial appears to lag far behind that of its close relative, chitosan, due to the perceived difficulty in processing chitin. This review presents methods to improve the processability of chitin, and goes on further to discuss the unique physicochemical and biological characteristics of chitin that favor it as a biomaterial for regenerative medicine applications. Examples of the latter are presented, with special attention on the qualities of chitin that make it inherently suitable as scaffolds and matrices for tissue engineering, stem cell propagation and differentiation.     

Biomaterials based on chitin and chitosan in wound dressing applications

Wound dressing is one of the most promising medical applications for chitin and chitosan. The adhesive nature of chitin and chitosan, together with their antifungal and bactericidal character, and their permeability to oxygen, is a very important property associated with the treatment of wounds and burns. Different derivatives of chitin and chitosan have been prepared for this purpose in the form of hydrogels, fibers, membranes, scaffolds and sponges. The purpose of this review is to take a closer look on the wound dressing applications of biomaterials based on chitin, chitosan and their derivatives in various forms in detail.     

Current views on fungal chitin/chitosan, human chitinases, food preservation, glucans, pectins and inulin: A tribute to Henri Braconnot, precursor of the carbohydrate polymers science, on the chitin bicentennial

Two hundred years ago, Henri Braconnot described a polysaccharide containing a substantial percent of nitrogen, later to be called chitin: that discovery stemmed from investigations on the composition of edible mushrooms and their nutritional value. The present interdisciplinary article reviews the major research topics explored by Braconnot, and assesses their importance in the light of our most advanced knowledge. Thus, the value of fungi, seafoods and insects is described in connection with the significance of the presence of chitin itself in foods, and chitinases in the human digestive system. The capacity of chitin/chitosan to depress the development of microbial pathogens, is discussed in terms of crop protection and food preservation. Other topics cherished by Braconnot, such as the isolation of pectin from a large number of plants, and inulin from the Helianthus tubers, are presented in up-to-date terms. Acids isolated from plants at that early time, led to enormous scientific advancements, in particular the glyoxylic acid and levulinic acid used for the preparation of soluble chitosan derivatives that paved the way to a number of applications. An opportunity to trace the origins of the carbohydrate polymers science, and to appreciate the European scientific heritage.     

GENDER INFLUENCES DIFFERENTIATION OF CHITIN AMONG BODY PARTS

Earlier reports have established that chitin isolates from each body part of an insect cuticle can exhibit diverse physicochemical properties. But it is still unknown if the gender of the insect can influence characteristics of chitin isolates from different body parts. The present study addresses this question. As a result, important physicochemical differences in the chitin samples from different body parts of Melolontha sp. were recorded on the basis of sex. The chitin samples were extracted from eight different body parts (antennae, head, eyes, thorax, abdomen, elytra, hindwings, and legs) of female and male. The most remarkable variations in the chitin isolates from female and male body parts were recorded in chitin content, crystallinity, thermal stability, and surface morphology. And also it was wondered these chitin isolates from different body parts of female and male could find different applications. To check this hypothesis, the chitin samples from female and male were interacted with bovine serum albumin (BSA) protein and important variations were observed.     

Effects of nitrogen delivery on chitin nanofiber production during batch cultivation of the diatom <Emphasis Type="Italic">Cyclotella</Emphasis> sp. in a bubble column photobioreactor

The photosynthetic diatom Cyclotella sp. extrudes chitin nanofibers following cell division. This diatom requires silicon for cell wall biosynthesis and division, as well as nitrogen for biosynthesis of intracellular material and extracellular chitin, an N-acetyl glucosamine biopolymer. The initial nitrogen/silicon molar ratio was the critical parameter for assessing the limits of nitrogen delivery on cell number and chitin production during batch cultivation of Cyclotella in a bubble column photobioreactor under silicon-limited growth conditions, using nitrate as the nitrogen source. The peak rate of volumetric chitin production increased linearly, from 3.0 to 46 mg chitin L^?1 day^?1, with increasing N/Si ratio over the range studied (0.82 to 8.6 mol N mol^?1 Si). However, the cell number yield and the chitin yield per cell increased asymptotically with increasing N/Si ratio, achieving a final cell number yield of 5.3?×?10⁹?±?2.6?×?10⁸ cells mol^?1 Si and chitin yield of 28.7?±?1.2 mg chitin per 10⁹ cells (1.0 S.E.). An N/Si ratio of at least 4.0 mol N mol^?1 Si achieved 90% of the asymptotic chitin yield. This study has shown that scalable cultivation systems for maximizing chitin nanofiber production will require delivery of both silicon and optimal nitrogen under silicon-limiting growth conditions to promote cell division and subsequent chitin formation.     

Biocontrol of wood-rotting fungi with Streptomyces violaceusniger XL-2

During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years because of their broad applications in medical, agricultural, and industrial applications, such as antibacterial, antifungal, hypo cholesterolemic, and antihypertensive activity, and as food quality enhancer. Fungal cell walls being rich in chitin also enable the use of chitinases in biocontrol of fungal pathogens, as bio-fungicides. An actinomycete was isolated from the bark of trees of Dehradun in India and was later identified as Streptomyces violaceusniger. This strain exhibits strong antagonism towards various wood-rotting fungi, such as Phanerochaete chrysosporium, Postia placenta, Coriolus versicolor, and Gloeophyllum trabeum. Further, studies showed an extracellular bioactive compound was responsible for the antagonism. The conditions for the production of this biocontrol agent were optimized, and the effects of various stress factors (like nitrogen-deficient media, carbon-deficient media, etc.) were studied. The presence of chitin in the growth media was found to be an essential factor for the active production of the biocontrol agent. The pH and temperature optima for the biocontrol agent were determined. Purification and characterization of this specific biocontrol agent was performed through anion exchange chromatography using a DEAE-cellulose column, and a single protein band was obtained on a 10% sodium dodecyl sulfate-polyacrylamide gel. The protein was later identified as a 28 kDa endo chitinase by MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) and by a chitobiose activity assay.     

Novel chitin and chitosan nanofibers in biomedical applications

Chitin and its deacetylated derivative, chitosan, are non-toxic, antibacterial, biodegradable and biocompatible biopolymers. Due to these properties, they are widely used for biomedical applications such as tissue engineering scaffolds, drug delivery, wound dressings, separation membranes and antibacterial coatings, stent coatings, and sensors. In the recent years, electrospinning has been found to be a novel technique to produce chitin and chitosan nanofibers. These nanofibers find novel applications in biomedical fields due to their high surface area and porosity. This article reviews the recent reports on the preparation, properties and biomedical applications of chitin and chitosan based nanofibers in detail.     

Chitin deacetylases: new, versatile tools in biotechnology

Chitin deacetylases have been identified in several fungi and insects. They catalyse the hydrolysis of N-acetamido bonds of chitin, converting it to chitosan. Chitosans, which are produced by a harsh thermochemical procedure, have several applications in areas such as biomedicine, food ingredients, cosmetics and pharmaceuticals. The use of chitin deacetylases for the conversion of chitin to chitosan, in contrast to the presently used chemical procedure, offers the possibility of a controlled, non-degradable process, resulting in the production of novel, well-defined chitosan oligomers and polymers.     

Prevention of Death of Axotomized Hypoglossal Neurones and Promotion of Regeneration by Chitin Grafting

1. Chitin is known to promote skin wound healing. In this study, chitin, prepared from Zuwai crab shell, was used as a bridge between the proximal and distal stumps of cut hypoglossal nerves in shrews. We compared the effects of chitin on the regeneration of transected right hypoglossal nerve axons, with those of porcine dermis, bovine dermal aterocollagen, and autologous nerve bundles.2. To assess the survival of neurones, the size of neuronal cell body, and number of motoneurones were determined in the absence of any bridged material and in the presence of porcine dermis, bovine dermal aterocollagen, chitin, or autologous nerve bundles as a bridge.3. Our results revealed a significantly better outcome in chitin and autologous nerve bridged groups; the size of neuronal cell body and number of hypoglossal neurones were higher than in the other groups. Chitin also enhanced the regeneration of neurones; the number of horseradish peroxide positive neurones indicative of repaired axonal processes was significantly higher in chitin and autologous nerve-bridged groups than in other groups.4. Our results demonstrated that the use of chitin sheet or autograft successfully prevented the death of severed neurones and promoted the regeneration of the lesioned nerve. Although the mechanisms underlying the effects of chitin are still unknown, chitin seems to be a potentially useful biocompatible material for nerve repair and regeneration.     

Chitin and chitosan biopolymer production from the Iranian medicinal fungus Ganoderma lucidum: Optimization and characterization

Abstract

Chitin and chitosan with unique properties and numerous applications can be produced from fungus. The production of chitin and chitosan from the mycelia of an Iranian Ganoderma lucidum was studied to improve cell growth and chitin productivity. Inoculum size and initial pH as two effective variables on the growth of G. lucidum and chitin production were optimized using response surface method (RSM) by central composite design (CCD). The results verified the significant effect of these two variables on the cell growth and chitin production. In optimum conditions, including pH?=?5.7 and inoculum size of 7.4%, the cell dry weight was 5.91?g/L and the amount of chitin production was 1.08?g/L with the productivity of 0.083?g/(L day). The produced chitin and chitosan were characterized using XRD and FTIR. Moreover, the antibacterial activity of the produced chitosan was investigated and compared with the commercial chitosan. The results showed that the produced chitin and chitosan had suitable quality and the Iranian G. lucidum would be a great source for safe and high-quality chitin and chitosan production.     

Studies on applications of chitin and its derivatives

Chitin, a homopolymer of N-acetylglucosamine, is obtained from a variety of sources. They form the structural component of fungal cell wall and plants. They are commercially obtained from shrimp and crab shell waste from the fishing industry. Recent advances in understanding the structure and properties of chitin and its derivatives has opened a lot of new avenues for its applications. Improvements in the properties of chitin for a particular application can be easily brought about by chemical modifications. The applicability of chitin in many areas and its easy manipulation has resulted in a considerable amount of research being done on the possible applications of chitinase.     

Preparation of biodegradable chitin/gelatin membranes with GlcNAc for tissue engineering applications

Chitin is a natural biopolymer have been used for several biomedical applications due to its biodegradability and biocompatibility. By using the calcium solvent system, chitin regenerated hydrogel (RG) was prepared by using -chitin. And also, the swelling hydrogel (SG) was prepared by using β-chitin with water. Then, both RG and SG were mixed with gelatin and N-acetyl-d-(+)-glucosamine (GlcNAc) at 120 °C for 2 h. The chitin/gelatin membranes with GlcNAc were also prepared by using RG and SG with GlcNAc. The prepared chitin/gelatin membranes with or without GlcNAc were characterized by mechanical, swelling, enzymatic degradation, thermal and growth of NIH/3T3 fibroblast cell studies. The stress and elongation of chitin/gelatin membrane with GlcNAc prepared from RG was showed higher than the chitin/gelatin membranes without GlcNAc. But, the chitin/gelatin membranes prepared from SG with GlcNAc was showed higher stress and elongation than the chitin/gelatin membranes without GlcNAc. It is due to the crosslinking effect of GlcNAc. The chitin/gelatin membranes prepared from SG showed higher swelling than the chitin/gelatin membranes prepared from RG. In contrast, the chitin/gelatin membranes prepared from RG showed higher degradation than the chitin/gelatin membranes prepared from SG. And also, these chitin/gelatin membranes are showing good growth of NIH/3T3 fibroblast cell. So these novel chitin/gelatin membranes are useful for tissue engineering applications.     

Chitosan as antimicrobial agent: applications and mode of action

Chitosan, a hydrophilic biopolymer industrially obtained by N-deacetylation of chitin, can be applied as an antimicrobial agent. The current review of 129 references describes the biological activity of several chitosan derivatives and the modes of action that have been postulated in the literature. It highlights the applications of chitosan as an antimicrobial agent against fungi, bacteria, and viruses and as an elicitor of plant defense mechanisms.