US 5,567,451 A · Alginate or pectate gel deficient in gelling ions for use in binding metal ions

Abstract

An ionically gellable material is gelled with a metal cation and the metal cation content of the gel is reduced to provide the gel with binding sites not occupied by the metal cation so the gel can be used to bind and remove metal cations from solution. In a preferred embodiment, a calcium alginate or calcium pectate gel in the form of beads is prepared, the calcium ion content of the gel is reduced to between 0.01 mg/g and 1.5 mg/g of moist gel by contacting the gel with an aqueous solution of acid such as lactic or tartaric acid having a pH of 1 to 3.5. The gel can be produced containing a microorganism such as yeast used for fermentation so metal ions can be removed while fermenting with the microorganism. In the bottle fermentation of wine to produce champagne, the gel containing yeast is added to the wine in the bottle. During fermentation, calcium and potassium ions are bound by the gel to reduce the precipitation of calcium tartrate and/or potassium bitartrate. Other uses of the gel include binding metal ions which can be other than calcium ions to provide metal ions for regulating enzymic activity or for recognizing, binding or purifying organic materials such as proteins or amino acids.

Claims60

Dependent claims

A method of preparation of a solid gel selected from the group consisting of an alginate and a pectate gel, said gel being partially deficient in calcium ions, comprising the successive steps of:

(a) preparing a solution of a solubilized form of said gel selected from the group consisting of alginic acid, pectic acid, water-soluble salts of alginic acid, and water-soluble salts of pectic acid,
(b) preparing a solution of a calcium salt capable of gelling said solution of said solubilized form of said gel,
(c) contacting said solution of said solubilized form of said gel with said calcium salt solution under conditions capable of gelling said solubilized form of said gel as a calcium alginate or pectate gel, wherein said calcium alginate or pectate gel has a calcium ion content corresponding substantially to saturation of the binding sites of the alginate or pectate gel,
(d) reducing by ion exchange of calcium ions with protons the content of said calcium ions in the alginate or pectate gel by contacting said gel with an aqueous solution of acid having a pH between 1 and 3.5 during a period of time sufficient to lower the content of said calcium ions in said gel to between about 0.01 mg/g and about 1.5 mg/g of moist alginate or pectate gel, so that said gel is deficient in calcium ions, has ionic binding sites resulting from the absences of said calcium ion and has an affinity for ions capable of binding to said gel at binding sites not occupied by calcium ions, and
(e) recovering said calcium alginate or pectate gel partially deficient in cation ions, whereby said gel has an affinity for ions capable of binding to said gel at said binding sites not occupied by calcium ions.

2 more elements

A solid alginate or pectate gel partially deficient in ionic gelling entity formed by a process comprising the successive steps of:

(a) preparing a solution of a solubilized form of said gel selected from the group consisting of alginic acid, pectic acid, water-soluble salts of alginic acid, and water-soluble salts of pectic acid,
(b) preparing a solution of an ionic gelling entity capable of gelling said solution of said solubilized form of said gel,
(c) contacting said solution of said solubilized form of said gel with said solution of said ionic gelling entity under conditions capable of gelling said solubilized form of said gel as an alginate or pectate gel, wherein said alginate or pectate gel has an ionic gelling entity content corresponding essentially to saturation of the binding sites of the alginate or pectate gel,
(d) reducing by ion exchange of the ions of said gelling entity with protons, the content of said ion gelling entity in the alginate or pectate gel by contacting said gel with an aqueous solution of acid having a pH between 1 and 3.5 during a period of time sufficient to lower the content of said ion gelling entity in said gel to between 0.005 times and 0.75 times said content of ion gelling entity corresponding essentially to saturation of the binding sites of the alginate or pectate gel, so that said gel is deficient in ion gelling entity, as ionic binding sites resulting from the absences of said ion gelling entity and has an affinity for ions capable of binding to said gel at binding sites not occupied by said ion gelling entity, and
(e) recovering said alginate or pectate gel partially deficient in ionic gelling entity, whereby said gel has an affinity for ions capable of binding to said gel at said binding sites not occupied by said ionic gelling entity.

2 more elements

A method of preparation of a solid gel selected from the group consisting of an alginate and a pectate gel, said gel being partially deficient in an ionic gelling entity, comprising the successive steps of:

(a) preparing a solution of a solubilized form of said gel selected from the group consisting of alginic acid, pectic acid, water-soluble salts of alginic acid, and water-soluble salts of pectic acid,
(b) preparing a solution of an ionic gelling entity capable of gelling said solution of said solubilized form of said gel,
(c) contacting said solution of said solubilized form of said gel with said solution of said ionic gelling entity under conditions capable of gelling said solubilized form of said gel as an alginate or pectate gel, wherein said alginate or pectate gel has an ionic gelling entity content corresponding essentially to saturation of the binding sites of the alginate or pectate gel,
(d) reducing by ion exchange of the ions of said gelling entity with protons, the content of said ion gelling entity in the alginate or pectate gel by contacting said gel with an aqueous solution of acid having a pH between 1 and 3.5 during a period of time sufficient to lower the content of said ion gelling entity in said gel to between 0.005 times and 0.75 times said content of ion gelling entity corresponding essentially to saturation of the binding sites of the alginate or pectate gel, so that said gel is deficient in ion gelling entity, as ionic binding sites resulting from the absences of said ion gelling entity and has an affinity for ions capable of binding to said gel at binding sites not occupied by said ion gelling entity, and
(e) recovering said alginate or pectate gel partially deficient in ionic gelling entity, whereby said gel has an affinity for ions capable of binding to said gel at said binding sites not occupied by said ionic gelling entity.

2 more elements

Dependencies are inferred from the claim text.

Alginate or pectate gel deficient in gelling ions for use in binding metal ions

Life of this patent

Alginate or pectate gel deficient in gelling ions for use in binding metal ions

Life of this patent

Abstract

Claims60