| 摘要 |
A process for producing modified heteropolysaccharides derived from a bacteria of the genus Xanthomonas, comprising the steps: (a) preparing an aqueous solution which contains (i) from about 200 to about 30,000 parts per million, by weight of an impure and unmodified heteropolysaccharide product and (ii) at least about 0.5 weight percent of at least one salt to obtain a saline heteropolysaccharide solution; (b) heating said saline heteropolysaccharide solution to a temperature of at least about 100 DEG C.; (c) maintaining said saline heteropolysaccharide solution at a temperature of at least about 100 DEG C. for a period of time sufficient to increase the injectivity and filterability characteristics of the heteropolysaccharide but for an insufficient time to impair the viscosity imparting properties of the heteropolysaccharide; and (d) removing or separating the proteinaceous materials and/or residual whole bacterial cells or other cell debris from the saline and heat-treated heteropolysaccharide product. The solution is preferably filtered or otherwise treated to separate the modified heteropolysaccharide from bacterial cells, cellular debris and other materials, prior to being put to use in, e.g., oil recovery processes, additive for foodstuffs, pharmaceutical preparations, etc.
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