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Low molecular weight chitosans--preparation by depolymerization with Aspergillus niger pectinase, and characterization.

Farooqahamed S Kittur·Acharya B Vishu Kumar·Rudrapatnam N Tharanathan
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Abstract

The viscosity of a chitosan solution was rapidly lowered in the presence of pectinase from Aspergillus niger at pH 3.0 and 37 degrees C. The low molecular weight chitosans (LMWC) had a molecular weight in the range 20,000-5000 Da. Circular dichroism spectra showed a decrease in the segment of acetylated glucosamine units, whereas X-ray diffraction and CP-MAS 13C NMR indicated higher crystallinity and polymorphism in LMWC. The latter on thermal drying resulted in structural alterations, and yielded an insoluble product. FT-IR and X-ray diffraction showed no evidence of either Schiff's base linkage or any annealed polymorph. CP-MAS 13C NMR showed marked changes in the chain conformations of LMWC, which are believed to be responsible for its loss of solubility and functionality.

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AcetylationAspergillus nigerCarbohydrate SequenceChitinChitinasesChitosanCircular DichroismGlycoside HydrolasesMagnetic Resonance SpectroscopyMolecular Sequence DataMolecular StructureMolecular WeightPolygalacturonasePolymersSolubilitySpectroscopy, Fourier Transform InfraredTime FactorsViscosityX-Ray DiffractionJournal ArticleResearch Support, Non-U.S. Gov't

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Farooqahamed S Kittur, Acharya B Vishu Kumar, Rudrapatnam N Tharanathan. 2003-06-16. Low molecular weight chitosans--preparation by depolymerization with Aspergillus niger pectinase, and characterization.. https://doi.org/10.1016/s0008-6215(03)00175-7

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