PROCESS FOR PREPARING BIOMEDICAL GRADE CHITIN AND CHITOSAN

摘要

The present invention provides a process for preparing a biomedical grade chitin of a high purity and whiteness with a high molecular weight and a biomedical grade chitosan of a high degree of deacetylation and high molecular weight from the chitin produced in accordance with the present invention. Specifically, the process for preparation of the chitin in accordance with the present invention comprises the steps of: (A) drying crustaceous shells and crushing the dried shells to provide a finely crushed powder; (B) digesting initially the powder in a HCl solution at a temperature ranging from -10 to 10.degree.C for a period ranging from 10 to 25 hours and, thereafter, further digesting the powder in the HCl solution at a temperature ranging from 10 to 20.degree.C for a period ranging from 2 to 8 hours; (C) washing with water, filtering, rinsing with a an organic solvent and drying the HCl-treated material to provide a crude chitin; (D) soaking and heating the crude chitin in a NaOH solution; and (E) washing with water, filtering, rinsing with the organic solvent and drying the NaOH-treated chitin to obtain the high purity chitin.