Chitin/chitosan enzymatic depolymerization

Pelletier, A., Lemire, I., Sygusch, J., Chomet, E., Overend, R.P. Chitin/chitosan transformation by thermo-mechano-chemical treatment including characterization by enzymatic depolymerization. Biotechnol. Bioeng. 36, 310-315 (1990)... 

Overcoming the problems of acid hydrolysis, scientists have adopted different enzymatic hydrolysis methods using different types of enzymes for the preparation of COS. The polysaccharide structure of the chitin or chitosan is converted to oligosaccharide form by specific enzymatic depolymerization or nonspecific enzymatic depolymerization. 

Muzzarelli RAA (1997) Human enzymatic activities related to the therapeutic administration of chitin derivatives. Cell Mol Life Sci 53 131-140 Muzzarelli RAA, Xia W, Tomasetti M and Ilari P (1995) Depolymerization of chitosan and substituted chitosans with the aid of a wheat germ lipase preparation. Enz Microbial Tech 17 541-545... 

The A. coerulea material was poorly crystalline, showing a broad peak at 20° 20, but the spectrum for the alkali-treated material showed a broad peak at 10.72° and two peaks at 18.72° and 19.98° 20, with close similarity to the spectrum of authentic chitosan. Optical microscopy showed that the alkali-treated products, stained with Saphranine or with other stains, preserved the morphology of the fungus, with flattened and empty structures [30] (Fig. 1). This work introduced the concept that an extended surface area of the carbohydrate polymer leads to enhanced performance, as amply confirmed by most recent works dealing with chitin and chitosan nanofibrils. In fact, the partially re-acetylated chitosan (degree of acetylation 0.23) is promptly depolymerized by lysozyme, papain, and lipase thanks to the ideal degree of acetylation for maximum enzymatic activity. Remarkably, the re-acetylated... 

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