| 摘要 |
PURPOSE:To obtain the title chitosan 340-50,000 in molecular weight, by continuously adding an acid to a chitosan-contg. reaction system while controlling its addition rate and by carrying out enzymatic reaction while retaining the pH of the system at a constant level in a range of 3-9. CONSTITUTION:Firstly, natural-occurring chitin is immersed in an alkaline solution 40-50wt.% in concentration and heat-treated normally at 115-130 deg.C for ca. 5h to effect deacetylation followed by removal of the alkaline solution and then washing the product with water followed by drying, thus obtaining a flaky chitosan. Thence, a reaction system containing this chitosan is continuously spiked with an acid while controlling its addition rate, and an enzymatic reaction is carried out while keeping the pH of the system at a virtually constant level in a range of 3-9, thus obtaining the objective chitosan 340-5,000 in molecular weight free from D-glucosamine. The enzyme to be used is pref. one to be produced by microorganisms classified as Bacillus. |
