| 摘要 |
Preparing a polysaccharide (A) that is heat treated and also hydrolyzed (A1); deacetylated (A2) or both hydrolyzed and deacetylated (A3), comprising bacterial culture, filtration and drying processes, is new. Preparing a polysaccharide (A) that is heat treated and also hydrolyzed (A1); deacetylated (A2) or both hydrolyzed and deacetylated (A3), comprises, to produce (A1), the bacterium CNCM I-1809 is grown in a medium rich in glucose and nitrogen sources to form a culture broth, which is diluted up to 1/20 with water; heated at 70-130 [deg]C, then centrifuged and subjected to tangential filtration to obtain a supernatant, which is passed through a 0.22 micron filter. The filtrate is concentrated by treatment with a first solvent (preferably ethanol), the precipitate recovered and dried to give a heat-treated polymer (P). A solution of (P), 10 g/l, is adjusted to pH 1-3 by adding acid and the mixture stirred at 70-95 [deg]C to produce a solution of viscosity 1-6 mPa.s at 25 [deg]C (10 g/l), particularly comprising addition of hydrochloric acid to pH 2.2 and hydrolysis for 60-240 minutes. The final solution is treated with a second alcohol and the precipitate separated and dried to give (A1). To produce (A2), 0.2-60 g/l of (P) are dissolved in a first solution, with 0.01 N base added per g, by stirring for at least 10 minutes (for deacetylation), then the solution treated with acid to pH 4.5-6.5 and treated with a third solvent to form a precipitate that is dried to give (A2). To produce (A3), 0.2-60 g/l (P) are dissolved in an aqueous solution, or a solution of (A1) is treated with base to pH 5-7, then 0.01 N base added per g and the mixture stirred for 10 minutes. The solution is adjusted to pH 4.5-6.4 with acid, then treated with an alcohol and the precipitate recovered and dried to give (A3). Independent claims are also included for: (1) (A1), (A2) and (A3) as new compounds; and (2) a composition comprising (A1), (A2) and (A3). |
