Structural Characterization of Chitin and Chitosan Obtained by Biological and Chemical Methods

Abstract

Chitin production was biologically achieved by lactic acid fermentation (LAF) of shrimp waste (Litopenaeus vannameii) in a packed bed column reactor with maximal percentages of demineralization (D(MIN)) and deproteinization (D(PROT)) after 96 h of 92 and 94%, respectively. This procedure also afforded high free astaxanthin recovery with up to 2400 μg per gram of silage. Chitin product was also obtained from the shrimp waste by a chemical method using acid and alkali for comparison. The biologically obtained chitin (BIO-C) showed higher M(w) (1200 kDa) and crystallinity index (I(CR)) (86%) than the chemically extracted chitin (CH-C). A multistep freeze-pump-thaw (FPT) methodology was applied to obtain medium M(w) chitosan (400 kDa) with degree of acetylation (DA) ca. 10% from BIO-C, which was higher than that from CH-C. Additionally, I(CR) values showed the preservation of crystalline chitin structure in BIO-C derivatives at low DA (40-25%). Moreover, the FPT deacetylation of the attained BIO-C produced chitosans with bloc copolymer structure inherited from a coarse chitin crystalline morphology. Therefore, our LAF method combined with FPT proved to be an affective biological method to avoid excessive depolymerization and loss of crystallinity during chitosan production, which offers new perspective applications for this material.

Determination of the degree of acetylation and the distribution of acetyl groups in chitosan by HPLC analysis of nitrous acid degraded and PMP labeled products

“…[14,15] M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 Chitin and chitosan are different from most of clinical used drugs in that they are not pure compounds but a mixture of polysaccharides with variable DA, molecular weight distribution, and purity depending on the source of raw materials and methods used for preparations. [16,17] At present it is largely unknown how the acetylated and deacetylated glucosamine residues distribute in the chitin/chitosan polysaccharide chains, an important structure feature related to their biological activities. Therefore, the DA and the distribution of acetylated glucosamine residues in chitin/chitosan are two important parameters highly desirable in defining the quality of chitin/chitosan for the purposes of medical applications.…”

Description of New Bioelectromechanical Properties in Alginate: An Insight with a Computer Simulation

“…X-ray structural parameters from alginate powder shows a very crystalline material corresponding tocristobalite crystalline solid (Figure 2). In the case the IR spectra, they show the characteristics set of SiO 2 bands from biosilica [33], alginate [40] [41] and chitin [42] [43]. Concretely, the band at 3437 cm −1 is due to the stretching vibration of -OH group and correspondingly, the IR band at ca.1617 cm confirms the presence of this molecule in diatom biosilica as described already [45].…”

Discerning the Potential of Chitosan Extracted from Bio Resources as a Competent Brain Drug Carrier to Cross the Blood Brain Barrier

“…Biopolymers are polymers produced by living organisms and chitosan is a natural polymer obtained by deacetylation of chitin. Further it has better stability and versatility of being applicable to various routes of drug administration [1] . The deacetylated chitosan consists of glucosamine units as the backbone, which has a high density of charged amine groups, permitting strong electrostatic interactions with proteins and genes that carry an overall negative charge at neutral pH [2] .…”