Biotechnologische Herstellung von niedermolekularem Chitosan aus Mucor Spezies als pharmazeutischer Hilfsstoff
A method for direct preparation of low molecular chitosan from fungi was developed, using mycelia from Absidia coerulea as raw material. Preliminary experiments with commercial chitosan gave evidence for a solubility of low molecular chitosan in aqueous medium up to alkaline pH. Furthermore, it could be shown that the use of water causes crystallinity and the agglomeration of molecules to occur, which leads to a measurement of higher molecular weights. Based on this the use of ethanol as a non-solvent for the production of chitosan from fungi was examined. This causes precipitation of the already solved chitosan by lowering the dielectricity constant of the preparational medium. Furthermore, the formation of agglomerates is minimized by eliminating the water through ethanol. Therefore low molecular weight chitosan can be directly prepared from the raw material, which after a final purification through dialysis presents a 1H-NMR-spectrum comparable to the reference chitosans. Low molecular weight chitosan form crab shells cannot be produced with this method.