Topic
Chitin
About: Chitin is a research topic. Over the lifetime, 6590 publications have been published within this topic receiving 253993 citations.
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01 Jan 1992TL;DR: Chitin is one of the most abundant organic materials, being second only to cellulose in the amount produced annually by biosynthesis as mentioned in this paper, and occurs in animals, particularly in crustacea, molluscs and insects where it is an important constituent of the exoskeleton.
Abstract: Chitin is one of the most abundant organic materials, being second only to cellulose in the amount produced annually by biosynthesis.1 It occurs in animals, particularly in crustacea, molluscs and insects where it is an important constituent of the exoskeleton, and in certain fungi where it is the principal fibrillar polymer in the cell wall. Its occurrence has been reviewed by Jeuniaux2 and by Richards3 and a table of the distribution of chitin in living organisms, adapted from that given by Jeuniaux,4 is given in Table 1.1.
111 citations
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TL;DR: In this paper, a nonlinear equilibrium isotherm was used to predict theoretical concentration versus time curves of dyestuffs on chitin, and the analysis was based on a computer program.
111 citations
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TL;DR: In this paper, the fabrication, properties, and applications of hydrogels prepared from two of the most abundant biopolymers on earth, cellulose and chitin, are discussed.
Abstract: This review is focused on the fabrication, properties, and applications of hydrogels prepared from two of the most abundant biopolymers on earth, cellulose and chitin. The review emphasizes the latest developments in hydrogel preparation (including solvent systems, cross-linker types, and preparation methods, which determine the “greenness” of the process) using these biocompatible and biodegradable biopolymers. The preparation of both physical (without covalent cross-links) and chemical (with covalent cross-links) hydrogels via dissolution/gelation is discussed. Additionally, formation of injectable thermoset and/or pH sensitive hydrogels from aqueous solutions of derivatives (chitosan, methyl cellulose, and hydroxypropylmethyl cellulose) with or without a cross-linker are discussed. This review also compares the design parameters for different applications of various pure and composite hydrogels based on cellulose, chitin, or chitosan, including applications as controlled and targeted drug delivery systems, improved tissue engineering scaffolds, wound dressings, water purification sorbents, and others.
111 citations
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TL;DR: It is suggested that the hydroxyl groups of C-3 and C-6 positions are equally substituted with the phosphate group, which means that chitin phosphates (P-chitins) are easily soluble in water independent of DS, while DA-ch itins of high DS are insoluble in water owing to the amphoteric property, while those of low DS are water soluble.
111 citations
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TL;DR: Owing to the simple purification process and high stability of the enzyme, it is potentially valuable for industrial applications and provides useful information for further gene cloning of this enzyme.
Abstract: A chitosan-degrading fungus, designated Aspergillus sp. Y2K, was isolated from soil. The micro-organism was used for producing chitosanase (EC 3.2.1.132) in a minimal medium containing chitosan as the sole carbon source. The induced chitosanase was purified to homogeneity from the culture filtrate by concentration and cationic SP-Sepharose chromatography. The purified enzyme is a monomer with an estimated molecular mass of 25 kDa by SDS/PAGE and of 22 kDa by gel-filtration chromatography. pI, optimum pH and optimum temperature values were 8.4, 6.5 and 65-70 degrees C, respectively. The chitosanase is stable in the pH range from 4 to 7.5 at 55 degrees C. Higher deacetylated chitosan is a better substrate. Chitin, xylan, 6-O-sulphated chitosan and O-carboxymethyl chitin were indigestible by the purified enzyme. By endo-splitting activity, the chitosanase hydrolysed chitosan to form chitosan oligomers with chitotriose, chitotetraose and chitopentaose as the major products. The enzyme hydrolyses chitohexaose to form chitotriose, while the chitopentaose and shorter oligomers remain intact. The N-terminal amino acid sequence of the enzyme was determined as YNLPNNLKQIYDDHK, which provides useful information for further gene cloning of this enzyme. A 275 g-scale hydrolysis of chitosan was performed. The product distribution was virtually identical to that of the small-scale reaction. Owing to the simple purification process and high stability of the enzyme, it is potentially valuable for industrial applications.
110 citations