Chitosan hydrolysis

Kuroiwa, T., Ichikawa, S., Sato, S., Hiruta, O., Sato, S., and Mukataka, S. 2002. Factors affecting the composition of oligosaccharides produced in chitosan hydrolysis using immobilized chitosanases. Biotechnol. Prog. 18 969-974. 

A possibility of using the viscosimetiy and sedimentation and diffusion methods in studying the process of enzyme chitosan hydrolysis is discussed in the chapter. It is shown that a change in the intrinsic viscosity of chitosan may be determined by both the hydrolysis process in the glycoside bonds and transformation of the supramolecule stmcture of the polymer. Thus, for setting the hydrolysis process it is necessary to use an absolute method for molecular weight determination. 

Characterization and Mechanism of Chitosan Hydrolysis by Non-specific Enzymes... 

However, few researches have been reported on the mechanism of these non-specific enzymatic processes, and even then controversial views exist. On the one hand, Kittur et al.[33] first reported that a multiple functional pectinase isoform from Aspergillus niger co i A be responsible for chitosan degradation by pectinases,but on the other hand, some authors have purified hetero chitosanases or/and chitinases from several commercial proteases,which were charged with their chitosanolytic activity [51-53].Whereas,no reports have been focused on non-specific hydrolysis of cellulases and lipases before, although their utility were popular in chitosan hydrolysis[5,8,9,10,28-31,43] and several bifunctional cellulase-chitosanases have been reported to be secreted from bacteria [58,79,87]. 

To make clear the non-specific mechanism for chitosan hydrolysis, taking the three typical non-specific enzymes cellulase, lipase and papain as objects, we have been working... 

In our recent study, we investigated the effects of a commercial lipase from A.oryzae on chitosan hydrolysis with different conditions such as pH,temperature,degree of deacetylation (DD) and molecular weights, metal ions,viscosity reduction, and qualitatively analyzed COS products using kinetic analysis,thin layer chromatography (TLC) and HPLC methods[48]. 

The CCBE showed different optimum condition and kinetic parameters on the two substrate chitosan and CMC (seen in Table 2).The optimum condition of CCBE on chitosan hydrolysis were pH 5.2 and 55°C, Km and V max were 0. 746 glucosamine mg/mL and 0.0268 mg.mL min respectively. Its chitosanase activity was stable at pH 4.0-7.8 and 30-50°C.It was gradually inactivated at 60°C and significantly lost activity at 80°C. However, the optimal condition toward CMC were pH 4.2 and 55°C, Km and Vmax were 4.087 glucose mg/mL and 0.127 mg.mL min Its CMCase activity was stable at pH4.0-6.0 and its temperature stability was consistent with that toward chitosan.From this, it can be seen that the CCBE probably had two distinct catalytic domains toward chitosan and CMC. 

Shinya, Y., Lee, M. Y., Hinode, H., et al. (2001). Effects of N-acetylation degree on N-acelylated chitosan hydrolysis with commercially available and modified pectinases. 

Liu, J. (2006). The mechanism of chitosan hydrolysis by cellulase. phD Dissertation. Jiangnan University.Wuxi. 

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