Shin-etsu Chemical Co., Ltd.

Shin-etsu Bio., Inc.

Taira Homma

Shigehiro Nagura

Kanji Murofushi

Richard W Armentrout

Kazumasa Maruyama

Kazuyuki Yamamoto

Sigehiro Nagura

A fermenter for the production of xanthan gum is provided with an upper helical impeller and a lower turbine impeller which are positioned therewithin, and an agitator shaft for driving these helical impeller and turbine impeller. The helical impeller consists of a pair of vertically spaced arms extending from the agitator shaft in opposite directions and arranged in twisted relationship, and at least one shearing paddle bridging these arms, and the turbine impeller consists of a rotating disc having at least one turbine blade attached thereto.

Apparatus for the production of xanthan gum

Xanthan gum is purified by heat-treating a xanthan gum fermented broth, and consecutively treating the broth first with alkaline protease and then with lysozyme or in reverse order, and thereafter recovering xanthan gum from the treated broth. A clear aqueous solution of xanthan gum may be obtained without complex procedures. The xanthan gum is separated and purified and 0.3% aqueous solution of the purified xanthan gum has a transmittance of at least 80%.

Process of purifying xanthan gum using an alkaline protease and lysozyme

Apparatus and method for the production of xanthan gum

The process comprises heat-treating a xanthan gum fermented broth, and consecutively treating the broth first with alkaline protease and then with lysozyme or in reverse order, and thereafter recovering xanthan gum from the treated broth. A clear aqueous solution of xanthan gum may be obtained without complex procedures.

Process for preparation of purified xanthan gum

A xanthan gum having an improved transmittance is disclosed. Further, the transmittance of the xanthan gum is at least 75% in an 1% by weight aqueous solution. The xanthan gum is prepared by subjecting a strain ATCC 55429 or ATCC 55298 to submerged fermentation conditions to produce a broth containing the gum and debris. The broth is then subjected to heating at a temperature from 45.degree. to 70 .degree. C. for a period of time of at least one half to two hours and at a pH of 9 to 12.5. Two enzyme treatments are performed using an alkaline protease and lysozyme of which the order of their application is irrelevant to the recovery of the xanthan gum. The enzymes are applied at specific temperatures and time periods as well as pH conditions such as a protease is applied at a temperature of 40.degree. to 65 .degree. C. for a period of from 20 minutes to five hours at a pH range of 6 to 10; and the lysozyme is applied at a temperature of 25.degree. to 60 .degree. C. for a period of 20 minutes to five hours at a pH range of 5.5 to 8.0. Both of the enzyme treatments are applied after the broth has been heated in step b) and before the recovery of the xanthan gum.

A xanthan gum-containing fermented solution is subjected to an enzyme treatment for solubilizing the microbial cells present in the fermented solution. While the fermented solution having undergone the enzyme treatment is maintained at a temperature of 50.degree. C. to 80.degree. C., and xanthan gum is precipitated by adding an hydrophilic organic solvent incapable of dissolving xanthan gum to the fermented solution. When a rotary turbine is used, the precipitate can be cut with a shearing cutter to recover a finely-divided fibrous product.

Process for the recovery and purification of xanthan gum

A method for continuously precipitating a polysaccharide dissolved in an aqueous solution wherein a non-solvent for the polysaccharide is admixed with the aqueous solution to cause the polysaccharide to precipitate from the solution. The method includes the step of simultaneously feeding the aqueous solution containing the dissolved polysaccharide and the non-solvent through respective constant flow rate-pumps to produce non-pulsating metered first and second streams which are unaffected by pressure changes in the aqueous solution or the non-solvent fed to the respective pumps. The metered streams are simultaneously introduced from the respective pumps into a rotary turbine to mix the solution and the non-solvent and precipitate the polysaccharide. The precipitated polysaccharide is cut with an interlocking cutter which comprises a fixed cutter and a rotary cutter, and a suspension of finely cut polysaccharide particles is continuously withdrawn.

Method for purifying polysaccharides

The process includes heat-treating a xanthan gum fermented broth, and consecutively treating the broth first with alkaline protease and then with lysozyme or in reverse order, and thereafter recovering xanthan gum from the treated broth. A clear aqueous solution of xanthan gum may be obtained Without complex procedures.

A method for continuously purifying a polysaccharide comprises the steps of continuously and simultaneously feeding an aqueous solution of a polysaccharide and a hydrophilic organic solvent which does not solubilize the polysaccharide, mixing these two kinds of liquids with a rotary turbine to precipitate the polysaccharide, cutting the precipitated polysaccharide with an interlocking cutter which comprises a fixed cutter and a rotary cutter, and continuously withdrawing a suspension of finely cut polysaccharide particles. The resulting polysaccharide is not in the form of strings, but in the form of fine particles and thus it is never adhered to an apparatus for purification and does not cause any retention within the apparatus. The particulate polysaccharides obtained by the method are easily separated from the resulting suspension and dehydrated.

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Joetsu, Japan

Taira Homma