Immobilization of psicose-epimerase and a method of producing D-psicose using the same
The present invention relates to a method of successively producing D-psicose from D-fructose or D-glucose by using a psicose-epimerase derived from Agrobacterium tumefaciens which is expressed in a food safety form.
1. A method of preparing D-psicose from D-fructose by using a psicose-epimerase isolated from Agrobacterium tumefaciens , and expressed in a GRAS (generally accepted as safe) strain, wherein the GRAS strain is Corynebacterium glutamicum KCCM 11046, said method comprising steps of:
expressing the psicose-epimerase isolated from Agrobacterium tumefaciens in the GRAS strain; and
preparing D-psicose from D-fructose by using the expressed psicose-epimerase.
2. The method of claim 1 , wherein the psicose-epimerase used in the preparation of D-psicose is contained in a culture of the GRAS strain or separated from the culture.
3. The method of claim 1 , wherein the psicose-epimerase isolated from Agrobacterium tumefaciens has the amino acid sequence of SEQ ID NO: 1.
4. The method of claim 1 , wherein the step of preparing D-psicose comprises the step of immobilizing the psicose-epimerase onto a carrier.
5. The method of claim 4 , wherein the carrier is sodium alginate.
6. The method of claim 4 , wherein the method further comprises the steps of packing a column with the carrier onto which the psicose-epimerase is immobilized and supplying the packed column with a D-fructose solution.
7. A method of preparing D-psicose from D-glucose, wherein psicose-epimerase is isolated from Agrobacterium tumefaciens and expressed in a GRAS (generally accepted as safe) strain, wherein the GRAS strain is Corynebacterium glutamicum KCCM 11046, comprising the step of immobilizing a psicose-epimerase and a D-glucose isomerase onto carriers.
8. The method of claim 7 , wherein the expressed psicose-epimerase is contained in a culture of the GRAS strain or separated from the culture.
9. The method of claim 8 , wherein the GRAS strain is a strain transformed with a recombinant vector including a gene encoding a psicose-epimerase.
10. The method of claim 8 , wherein the psicose-epimerase has the amino acid sequence of SEQ ID NO: 1.
11. The method of claim 7 , wherein the carrier is sodium alginate.
12. The method of claim 7 , wherein the method further comprises the steps of packing a column with the carriers onto which the psicose-epimerase and the D-glucose isomerase are immobilized and supplying the carrier-packed column with a D-fructose solution.
13. The method of claim 12 , wherein each of the carriers onto which the psicose-epimerase and the D-glucose isomerase are immobilized, respectively, is packed into a separate column, and the two columns are connected in communication with each other.