Temperature-programmed process for the production of levulose-bearing syrups

Claim 2

AN ENZYMATIC ISOMERIZATION PROCESS FOR THE CONVERSION OF DEXTROSE TO LEVULOSE, COMPRISING: IN AN INITIAL OPERATING PHASE, SUBJECTING A SOLUTION CONTAINING DEXTROSE TO THE ACTION OF A XYLOSE ISOMERASE ENZYME PREPARATION AT AN OPERATING TEMPERATURE OF AT LEAST 50*C., BUT NOT MORE THAN 70*C., THEN INCREASING THE TEMPERATURE TO A VALUE THAT IS AT LEAST 5* HIGHER THAN THE TEMPERATURE DURING THE INITIAL OPERATING PHASE, AND CONTINUING THE ISOMERIZATION PROCESS AT SAID INCREASED TEMPERATURE.

Claim 3

in a subsequent operating phase, increasing the temperature to a value that is at least 5* higher than the temperature during the initial operating phase.

Claim 4

in a subsequent operating phase, increasing the temperature to a value that is at least 5* higher than the temperature during the initial operating phase.

Claim 5

A process in acCordance with claim 1, wherein the temperature during the initial operating phase, is in the range from 50* C to 65* C.

Claim 6

A process in accordance with claim 1, wherein the temperature, after the initial operating phase, is increased gradually.

Claim 7

A process in accordance with claim 1, wherein the temperature, after the initial operating phase, is increased in a single step increment.

Claim 8

A process in accordance with claim 2, wherein the operating temperature, after the initial operating phase, does not exceed 80* C.

Claim 9

A continuous process for the isomerization of dextrose to levulose with a xylose isomerase enzyme preparation that comprises: in an initial operating phase, passing a stream of a solution containing dextrose into contact with an immobilized xylose isomerase enzyme preparation for an initial period of time at an operating temperature of at least 50* C, and then continuing the operation at a temperature higher than the temperature employed during the initial phase but that does not exceed 80* C, to maintain a desired ketose level in the effluent.

Claim 10

A continuous process for the isomerization of dextrose to levulose with a xylose isomerase enzyme preparation that comprises: in an initial operating phase, passing a stream of a solution containing dextrose into contact with an immobilized xylose isomerase enzyme preparation for an initial period of time at an operating temperature of at least 50* C, and then continuing the operation at a temperature higher than the temperature employed during the initial phase but that does not exceed 80* C, to maintain a desired ketose level in the effluent.

Claim 11

A process in accordance with claim 6, wherein the dextrose solution is a starch hydrolysate.

Claim 12

A process in accordance with claim 7, wherein the starch hydrolysate has a D.E. of at least 95.

Claim 13

A process in accordance with claim 6, wherein the dextrose solution is one prepared by dissolving crystalline dextrose in an aqueous medium.

Claim 14

A process in accordance with claim 6, wherein the stream of solution is passed into contact with the enzyme preparation at a pH of at least 7.

Claim 15

A process in accordance with claim 6, wherein the operating temperature during the initial phase of operations is in the range from 50* C to 65* C.

Claim 16

A process in accordance with claim 11, wherein the pH is maintained in the range from about 7.5 to 8.5.

Claim 17

A process in accordance with claim 12, wherein the enzyme preparation is derived from an organism of the Streptomyces genus.

Claim 18

A process in accordance with claim 6 comprising: continuing the operation in the second phase by raising the temperature in small increments.

Claim 19

A process in accordance with claim 6 comprising: continuing the operation in its second phase by raising the temperature at least 5* C higher than the operating temperature during the initial phase.

Claim 20

A continuous process for the isomerization of a solution containing dextrose, with a xylose isomerase enzyme preparation, that comprises: in an initial operating phase, passing a stream of a solution containing dextrose in an aqueous medium into contact with an immobilized xylose isomerase enzyme preparation derived from a microorganism of the Streptomyces genus at a pH of at least 7.0 and at a temperature of at least 50* C and up to about 65* C, then continuing the isomerization at a pH of at least 7.0 but at a temperature that is higher than the temperature employed during the initial phase but that does not exceed 80* C, to maintain a desired ketose level in the effluent, and recovering a levulose-bearing product.

Claim 21

A continuous process for the isomerization of a solution containing dextrose, with a xylose isomerase enzyme preparation, that comprises: in an initial operating phase, passing a stream of a solution containing dextrose in an aqueous medium into contact with an immobilized xylose isomerase enzyme preparation derived from a microorganism of the Streptomyces genus at a pH of at least 7.0 and at a temperature of at least 50* C and up to about 65* C, then continuing the isomerization at a pH of at least 7.0 but at a temperature that is higher than the temperature employed during the initial phase but that does not exceed 80* C, to maintain a desired ketose level in the effluent, and recovering a levulose-bearing product.

Claim 22

A process in accordance with claim 16, wherein the xylose isomerase preparation comprises intact cells of the microorganism.

Claim 23

A process in accordance with claim 16, wherein the isomerization is conducted at a pH in the range from about 7.5 to about 8.5.

Claim 24

A process in accordance with claim 18, wherein the dextrose solution initial material is a corn starch hydrolysate having a D.E. of at least 95.

Claim 25

A process in accordance with claim 16 comprising: continuing the isomerization by raising the temperature in small increments.

Claim 26

A process in accordance with claim 16 comprising: continuing the isomerization by raising the temperature at least 5* C higher than the operating temperature during The initial phase.

Claim 27

A process in accordance with claim 19 comprising: continuing the isomerization by raising the temperature at least 10* C higher than the operating temperature during the initial phase.

Claim 28

A process for the enzymatic conversion of dextrose to levulose, comprising:

Claim 29

A process for the enzymatic conversion of dextrose to levulose, comprising:

Claim 30

The process of claim 23, wherein the xylose isomerase enzyme is derived from a microorganism of the genus Streptomyces.

Claim 31

The process of claim 23, wherein said stabilized enzyme is packed in a column.