Recovering and purifying resveratrol produced by microbial fermentation

Patent metadata

Field	Value
Publication number	US-11136283-B2
Application number	US-201816481943-A
Country	US
Kind code	B2
Filing date	Jan 31, 2018
Priority date	Jan 31, 2017
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

The present invention relates to a process for recovering and purifying resveratrol produced by microbial fermentation. More particularly, the present invention relates to a process for recovering and purifying resveratrol produced by yeast fermentation.

First claim

The invention claimed is:

1. A process for recovering and purifying resveratrol from a microbial fermentation broth said process comprising:
(a) increasing the pH of the fermentation broth to about 11;
(b) separating and removing the host microbes such that a substantially microbe free liquid remains;
(c) decreasing the pH of the substantially microbe free liquid to a value which is no less than about 7 to about 8.5 such that crude resveratrol is precipitated;
(d) separating the precipitated crude resveratrol;
(e) dissolving the crude resveratrol recovered in step (c) in a purification solvent to form a crude resveratrol containing solution;
(f) contacting the solution produced in step (e) with one or more absorbents; and
(g) crystallizing the purified resveratrol from the purification solvent, said purified resveratrol having a lower concentration of impurities including bisnoryangonin than the precipitated crude resveratrol of step (c).

2. The process according to claim 1 where the one or more absorbents are selected from carbon, optionally activated carbon, ion exchange resins, and/or Al 2 O 3 .

3. The process according to claim 1 where step (f) comprises the steps of:
i) contacting the solution produced in step (e) with one or more absorbents selected from ion exchange resins and/or Al 2 O 3 ; and
ii) contacting the solution produced in step i) with carbon, optionally activated carbon.

4. The process according to claim 1 , wherein the host microbes are removed by ultrafiltration, pressure filtration, vacuum drum filtration, or cross-flow filtration.

5. The process according to claim 4 , wherein the host microbes are removed by ultrafiltration using an ultrafilter having a molecular weight cut-off of about 100 kDa to about 5 kDa or less.

6. The process according to claim 1 , wherein the process includes a concentration step before step (c).

7. The process according to claim 6 , wherein the concentration step is carried out by reverse osmosis.

8. The process according to claim 1 , wherein the reduction of pH in step (c) is achieved by the addition of sulphuric acid or hydrochloric acid.

9. The process according to claim 1 , wherein the purification solvent is selected from methanol, ethanol, propanol, acetone, ethyl acetate, and tetrahydrofuran.

10. The process according to claim 9 , wherein the purification solvent is ethanol.

11. The process according to claim 10 , wherein the resveratrol concentration of the solution formed in step (e) is in the region of from about 30 to about 50 g/L.

12. The process according to claim 3 , wherein the amount of carbon to which the solution formed in step (e) or step i) is contacted will be from about 1.5 kg to about 2 kg per kg of resveratrol.

13. The process according to claim 3 , wherein the solution formed in step (e) or step i) is contacted 3 times with 0.5 kg of carbon per kg of resveratrol.

14. The process according to claim 1 , wherein crystallisation in step (g) is achieved by decreasing the concentration of the solvent solution to about 40% to about 15% by volume.

15. The process according to claim 1 , wherein the precipitated crude resveratrol obtained in step (d) is subjected to pre-crystallisation before being passed to step (e), the pre-crystallisation comprising:
(x) dissolving the crude resveratrol recovered in step (d) in a first solvent; and
(y) crystallizing the resveratrol out of the first solvent, said resveratrol having a lower concentration of dihydroresveratrol impurities than present in the precipitated crude resveratrol.

16. The process according to claim 15 , wherein the first solvent is the same or different to the purification solvent.

17. The process according to claim 16 , wherein the first solvent is selected from methanol, ethanol, propanol, acetone, ethyl acetate, and tetrahydrofuran.

18. The process according to claim 17 , wherein the first solvent is ethanol.

19. The process according to claim 18 , wherein the ethanol concentration is about 65% to about 80% by volume.

20. The process according to claim 18 , wherein the ethanol is mixed at a temperature of about 50° C. to about 80° C.

21. The process according to claim 15 , wherein crystallisation in step (y) is achieved by decreasing the concentration of the solvent solution to about 40% to about 15% by volume.

22. The process according to claim 15 , wherein steps (x) and (y) are repeated.

23. A composition comprising at least about 70 wt % resveratrol, about 10 to about 5000 mg/kg dihydroresveratrol, and about 10 to about 5000 mg/kg pinosylvin, wherein the composition further comprises bisnoryangonin at a maximum concentration of about 5000 mg/kg as measured by dry weight ratio to resveratrol and wherein the composition is free of emodin.

24. The composition according to claim 23 , wherein the composition has about 2 wt % or less water.

25. The composition according to claim 23 , wherein the compound has a yellowness index of about 40 to about 5 or less.

26. The composition according to claim 23 , wherein the compound has a whiteness index of about −50 or less to about 100.

27. The composition according to claim 23 , wherein the composition is dissolved or suspended in a solvent.

Assignees

• Evolva Sa

Inventors

• Ohler Nicholas Lawrence
• Bachu Satish Kumar
• Frankovic Oliver

Classifications

• C07C37/84 Primary

  by crystallisation · CPC title

• C07C39/21

  with at least one hydroxy group on a non-condensed ring · CPC title

• C12P7/22 Primary

  aromatic · CPC title