Apart from the advantages of Chemical Deacetylation it also have disadvantages such as Energy Consumption, Waste of concentrated alkaline solution which results in increase of environmental pollution, broad and heterogeneous range of soluble and insoluble products.
An alternative enzymatic method has been discovered to overcome the limitation of preparation of chitosan by discovering chitin deacetylases . For production of novel, well-defined chitosan we have found the use of chitin deacetylases for the conversion of chitin to chitosan, which is in contrast to the currently used chemical procedure, offers the possibility of a controlled, non-degradable process . This method is specially used to prepare chitosan oligomers For production of chitosan we use…show more content… However, chitosan solution must be free of aggregates, and hence the solvent for chitosan must be chosen carefully. The viscometric average molecular weight is usually been calculated from intrinsic viscosity because of the lower impact of small fractions of aggregates, using the Mark-Houwink relationship. In order to determine K and a parameters, an absolute MW has to be calculated using light scattering technique and due to high sensitivity to aggregate formation the obtained value is usually overestimated. These artifacts may be carried out for instance by the use of 0.3M acetic acid/0.2M sodium acetate (pH = 4.5) solvent which does not form aggregates in this mixture. Under these conditions, the absolute M values were obtained from steric exclusion chromatography (SEC) equipped with viscometer and light scattering detector on line allowing to determine the Mark-Houwink parameters without fractionation and also to obtain the relation between the radius of gyration (G) and the molecular weight(MW). The K (mL/g) and a parameters at 25 °C are 7.9 × 10−2 and 0.796