Obtaining Chitosan from Chitine-Containing Raw Materials in Uzbekistan and Research on Antimicrobial Properties

Abstract

The optimal conditions for the isolation of valuable natural biopolymers were revealed. Chitosan (CH) was obtained from cysts of A. parthenogenetia in the Aral Sea and from pupae of the silkworm Bombyx mori. Chitosan was obtained from cysts of A. parthenogenetia with a molecular weight of 89 kDa, a degree of deacetylation (DDA) of 72% and a solubility of 81.62%. It has been shown that it is possible to isolate CH from silkworm pupae of sufficient purity with different molecular weights and DDAs depending on the synthesis conditions and the degree of purification. Bombyx mori CH has a higher molecular weight of 100–160 kDa, a high DDA, up to 90%, and a solubility of 88%. IR spectroscopy, X-ray diffraction and elemental analysis have shown the purity of the isolated CH from various sources. In chitin from A. parthenogenetia cysts of the Aral Sea, two types of modifications, α and β, with corresponding syngonies are observed, which confirms its polymorphic structure. The antibacterial activity of B. mori CH has been shown, which tends to expand the spectrum of suppressed bacteria with increasing concentration and have a bactericidal effect on both gram-negative and gram-positive bacteria. CH of B. mori had an immunostimulating effect on living organisms, which allows us to recommend drugs based on CH to strengthen the immune system.