Abstract: Disclosed are methods of producing modified microcrystalline chitosan. Chitosan in aqueous solution is degraded enzymatically, hydrolytically or oxidatively. The chitosan solution is then alkalized with agitation using aqueous hydroxides and/or their salts to attain a pH not lower than 7.0. The precipitated modified microcrystalline chitosan is highly pure and may be concentrated and dried according to known methods. Methods according to the invention also include methods by which an aqueous solution of chitosan is first alkalized using hydroxides and/or their salts to a pH not lower than 7.0. Then the precipitated microcrystalline chitosan is subjected to enzymatic or oxidative degradation to achieve a desired average molecular weight and polydispersity. The product is highly pure and may be concentrated and dried according to known methods.

Abstract: Disclosed are methods of producing modified microcrystalline chitosan. Chitosan in aqueous solution is degraded enzymatically, hydrolytically or oxidatively. The chitosan solution is then alkalized with agitation using aqueous hydroxides and/or their salts to attain a pH not lower than 7.0. The precipitated modified microcrystalline chitosan is highly pure and may be concentrated and dried according to known methods. Methods according to the invention also include methods by which an aqueous solution of chitosan is first alkalized using hydroxides and/or their salts to a pH not lower than 7.0. Then the precipitated microcrystalline chitosan is subjected to enzymatic or oxidative degradation to achieve a desired average molecular weight and polydispersity. The product is highly pure and may be concentrated and dried according to known methods.

Abstract: Disclosed are methods of producing modified microcrystalline chitosan. Chitosan in aqueous solution is degraded enzymatically, hydrolytically or oxidatively. The chitosan solution is then alkalized with agitation using aqueous hydroxides and/or their salts to attain a pH not lower than 7.0. The precipitated modified microcrystalline chitosan is highly pure and may be concentrated and dried according to known methods. Methods according to the invention also include methods by which an aqueous solution of chitosan is first alkalized using hydroxides and/or their salts to a pH not lower than 7.0. Then the precipitated microcrystalline chitosan is subjected to enzymatic or oxidative degradation to achieve a desired average molecular weight and polydispersity. The product is highly pure and may be concentrated and dried according to known methods.

Abstract: Disclosed are methods of producing modified microcrystalline chitosan. Chitosan in aqueous solution is degraded enzymatically, hydrolytically or oxidatively. The chitosan solution is then alkalized with agitation using aqueous hydroxides and/or their salts to attain a pH not lower than 7.0. The precipitated modified microcrystalline chitosan is highly pure and may be concentrated and dried according to known methods. Methods according to the invention also include methods by which an aqueous solution of chitosan is first alkalized using hydroxides and/or their salts to a pH not lower than 7.0. Then the precipitated microcrystalline chitosan is subjected to enzymatic or oxidative degradation to achieve a desired average molecular weight and polydispersity. The product is highly pure and may be concentrated and dried according to known methods.

Abstract: Methods for deproteinizing chitosan are provided. Proteins are dissolved in aqueous solution under intensive agitation. Precipitated agglomerated microcrystalline product Is subject to aqueous acidic or basic salt solution, from which dissolved proteins can be removed. Residual product is deproteinized chitosan.

Abstract: Chitosan-calcium complexes of calcium (II) ions with a gel of a chitosan salt, containing not less than 0.5 wt % of the polymer with an average molecular weight not less than 10 kD, a polydispersity degree not lower than 2.0 and a deacetylation degree at least 65%. The complex is characterized by pH not higher than 6.9 and a calcium Ca (II) ions content not less than 0.1 wt % on chitosan. Methods to prepare chitosan-calcium complexes use a gel of a chitosan salt, containing not less than 0.5 wt % of the polymer. Calcium salts are introduced in the amount of at least 0.1 wt % Ca (II) on chitosan weight. The mixture is next homogenized and reacted at 10° C. during a time not shorter than 1 minute. Methods of producing a gel of chitosan salts involves subjecting a chitosan with the concentration of at least 0.5 wt % in an aqueous acidic solution to a controlled enzymatic, hydrolytic or oxidative degradation.

Abstract: Disclosed are methods of producing modified microcrystalline chitosan. Chitosan in aqueous solution is degraded enzymatically, hydrolytically or oxidatively. The chitosan solution is then alkalized with agitation using aqueous hydroxides and/or their salts to attain a pH not lower than 7.0. The precipitated modified microcrystalline chitosan is highly pure and may be concentrated and dried according to known methods. Methods according to the invention also include methods by which an aqueous solution of chitosan is first alkalized using hydroxides and/or their salts to a pH not lower than 7.0. Then the precipitated microcrystalline chitosan is subjected to enzymatic or oxidative degradation to achieve a desired average molecular weight and polydispersity. The product is highly pure and may be concentrated and dried according to known methods.

Abstract: Disclosed is a process for producing particles of the modified carbohydrate polymer chitosan. Such chitosan particles are “activated” as a consequence of the specific steps used in the process. The process involves precipitation of dissolved chitosan from an acid solution thereof by the step-wise addition of neutralizing agent to the solution. A partial neutralization is carried out under shear agitation to form a continuous gel phase having a pH within the range of 5.0 to 6.9. This partially neutralized chitosan gel phase is then further subjected to shear agitation for at least 10 seconds to homogenize the gel phase. The homogenized gel phase is then further neutralized under shear agitation to a pH of above 6.9 to form a gel-like suspension of discrete chitosan particles. Chitosan particles in this form are useful in a number of contexts including, in particular, in the area of plant care.

Abstract: Disclosed are bioagent compositions for plant care which can be used for treatment of plants and seeds. Such treatment serves to inhibit the activity of plant pathogens against the treated plants, stimulate natural plant immunity against such pathogens and provides plant growth biostimulation. The compositions comprise a chitosan polymer which can either be in the form of particles of microcrystalline chitosan which are in a composition of pH greater than 6.9, or in the form of a chitosan salt gel which are in a composition of pH of from 5.0 to 6.9. In either form, the chitosan polymer has specified molecular weight, polydispersity degree and degree of deacetylation characteristics. Preferably the chitosan polymer has a bimodal molecular weight distribution and contains a fraction of water-soluble oligoaminocarbohydrates.

Abstract: Disclosed is a process for producing particles of the modified carbohydrate polymer chitosan. Such chitosan particles are “activated” as a consequence of the specific steps used in the process. The process involves precipitation of dissolved chitosan from an acid solution thereof by the step-wise addition of neutralizing agent to the solution. A partial neutralization is carried out under shear agitation to form a continuous gel phase having a pH within the range of 5.0 to 6.9. This partially neutralized chitosan gel phase is then further subjected to shear agitation for at least 10 seconds to homogenize the gel phase. The homogenized gel phase is then further neutralized under shear agitation to a pH of above 6.9 to form a gel-like suspension of discrete chitosan particles. Chitosan particles in this form are useful in a number of contexts including, in particular, in the area of plant care.

Abstract: Modified viscose fibres comprise regenerated cellulose and contain in their structure microcrystalline chitosan bound mainly by hydrogen bonds with the regenerated cellulose of viscose fibres. To improve the properties of the fibres the modified fibres contain as a third component a water-soluble and/or alkali-soluble natural polymer or a derivative thereof of polysaccharide origin containing groups bound by hydrogen and/or ionic bonds with the microcrystalline chitosan. Examples of such polymers are alginic acid, sodium and potassium alginate and sodium carboxymethycellulose.

Abstract: Poly(lactic acid) with a high molecular weight is produced by the polycondensation reaction of the free monomer carried out in the presence of a catalytically effective quantity of iron ions. High molecular weight poly(lactic acid) and lactide are obtained as the principal products.