Patent

1. A Bacillus subtilis strain BLCY-005 or a progeny thereof, wherein the strain BLCY-005 was deposited on Oct. 26, 2016 in the China General Microbiological Culture Collection Center, with an accession number of CGMCC No. 13152.

2. A method for culturing the Bacillus subtilis strain according to claim 1 , comprising a step of inoculating the strain or a progeny thereof into a medium.

3. The method according to claim 2 , wherein the method comprises the following steps:

(1) inoculating the strain or a progeny thereof into a solid medium and culturing at a temperature of 25-40° C. for 6-12 hours to obtain an activated strain;

(2) inoculating the activated strain obtained in the step (1) into a seed medium and culturing at a temperature of 25-40° C. for 6-12 hours to obtain a seed liquid;

(3) inoculating the seed liquid obtained in step (2) into a fermentation medium in a volume ratio of 1-10%, and culturing at a temperature of 25-40° C. for 30-48 h to obtain a bacterial fermentation broth.

4. A culture comprising the Bacillus subtilis strain or a progeny thereof according to claim 1 and a culture medium.

5. A lysate of a strain, wherein the strain is the Bacillus subtilis strain or a progeny thereof according to claim 1 .

6. A composition comprising fructose and at least one component selected from the group consisting of: (1) the strain or a progeny thereof according to claim 1 ; (2) a culture comprising the Bacillus subtilis strain or a progeny thereof; and (3) a lysate of the Bacillus subtilis strain or a progeny thereof.

7. A method for preparing a D-psicose epimerase, comprising a step of lysing the Bacillus subtilis strain or a progeny thereof according to claim 1 and isolating the D-psicose epimerase, or a step of isolating the D-psicose epimerase from a culture comprising the Bacillus subtilis strain or a progeny thereof or a lysate of the Bacillus subtilis strain or a progeny thereof.

8. A method for preparing a D-psicose, comprising any one of the following steps:

contacting the strain or a progeny thereof according to claim 1 with fructose;

contacting a culture comprising the strain or a progeny thereof with fructose;

contacting a lysate of the strain or a progeny thereof with fructose; and

isolating a D-psicose epimerase from the strain or a progeny thereof according to claim 1 , or a culture comprising the strain or a progeny thereof or a lysate of the strain or a progeny thereof, and contacting the D-psicose epimerase with fructose.

9. The method according to claim 2 , wherein the method comprises the following steps:

(1) inoculating the strain or a progeny thereof into a solid medium, and performing cultivation;

(2) inoculating the strain in the solid medium into a first medium, and performing cultivation;

(3) optionally, inoculating the strain in the first medium into a second medium, and performing cultivation.

10. The method according to claim 9 , wherein the method is characterized by one or more of the following items:

(a) the cultivation is performed at a temperature of 25-40° C. in step (1);

(b) the cultivation is performed at a temperature of 25-40° C. in step (2);

(c) the cultivation is performed at a temperature of 25-40° C. in step (3);

(d) the first medium is a seed medium;

(f) the second medium is a fermentation medium.

11. The method according to claim 3 , wherein the method is characterized by one or more of the following items:

(a) the seed medium comprises: 1% peptone, 0.5% yeast extract powder, 1% sodium chloride, 0.01% anhydrous magnesium sulfate, 0.02% potassium dihydrogen phosphate, and the balance of water (all percentages are weight percentages) in step (2);

(b) the seed medium has a pH of 6.0-7.0 in step (2);

(c) the fermentation medium comprises: 3% yeast extract powder, 2% corn steep powder, 1% glucose, 0.01% anhydrous magnesium sulfate, 0.02% diammonium hydrogen phosphate, 0.02% ammonium sulfate, and the balance of water in step (3);

(d) the fermentation medium has a pH of 6.0-7.0 in step (3);

(e) the solid medium is LB medium in step (1).

12. The composition according to claim 6 , wherein the fructose is obtained or provided in form of an aqueous crystalline fructose solution, liquid fructose, glucose-fructose syrup, dried fructose, or fructose syrup.

13. The method according to claim 7 , wherein the method comprises the following steps:

(1) culturing the strain under a condition that allows the growth of the strain or a progeny thereof to obtain a fermentation broth of the strain; and

(2) isolating the D-psicose epimerase from the fermentation broth obtained in step (1).

14. The method according to claim 13 , wherein the D-psicose epimerase is isolated from the fermentation broth by centrifugation, filtration, dialysis, or chromatography in step (2).

15. The method according to claim 13 , wherein the D-psicose epimerase is isolated from the fermentation broth in step (2) by the following steps:

(2a) centrifuging the fermentation broth obtained in step (1) to obtain a precipitate;

(2b) thermally denaturing the precipitate obtained in step (2a);

(2c) drying the product of step (2b) to obtain the D-psicose epimerase.

16. The method according to claim 15 , wherein the method is characterized by one or more of the following items:

(i) the precipitate obtained in step (2a) is thermally denatured at a temperature of 50-60° C. in step (2b);

(ii) the product of step (2b) is vacuum freeze-dried in step (2c);

(iii) the fermentation broth is centrifuged under a condition of 10000 r/min for 10 min at 4° C. in step (2a).

17. The method according to claim 8 , wherein the fructose is obtained or provided in form of an aqueous crystalline fructose solution, liquid fructose, glucose-fructose syrup, dried fructose, or fructose syrup.

18. The method according to claim 8 , wherein the method comprises the following steps:

(1) isolating a D-psicose epimerase from the strain or a progeny thereof according to claim 1 , or a culture comprising the strain or a progeny thereof or a lysate of the strain or a progeny thereof;

(2) contacting the D-psicose epimerase obtained in step (1) with fructose;

(3) optionally recovering D-psicose from the product of step (2).

19. The method according to claim 18 , wherein the D-psicose epimerase is contacted with fructose under a condition suitable for D-psicose epimerase activity in step (2).

20. The method according to claim 18 , wherein the D-psicose epimerase is contacted with fructose under a condition of pH 5.5-6.5 in step (2).