Methods for improving yields of a polyunsaturated fatty acid (PUFA) oil containing product using multiple centrifugation steps
This invention relates to a method of using a two-step serial centrifugation process in extracting nutritive oil from a fermentation broth, this novel method prevents oil yield losses while preserving product quality.
1. A method of improving product yield of a polyunsaturated fatty acid (PUFA) oil containing product, wherein the method comprises:
(a) directing a PUFA oil-containing fermentation broth to a first centrifuge and subjecting the PUFA oil-containing fermentation broth to a first centrifugation step within the first centrifuge to form a first centrifuged product comprised of a first light phase and a first heavy phase;
(b) separating the first light phase from the first heavy phase in the first centrifuged product by making a first separation cut of the first centrifuged product into the first heavy phase below an interface between the first light phase and the first heavy phase thereof;
(c) discarding the first heavy phase separated from the first centrifuged product and directing the first light phase separated from the first centrifuged product to a second centrifuge;
(d) subjecting the first light phase separated from the first centrifuged product to a second centrifugation step in the second centrifuge to form a second centrifuged product comprised of a second light phase and a second heavy phase;
(e) separating the second light phase from the second heavy phase in the second centrifuged product by making a second separation cut of the second centrifuged product in the second light phase close to an interface between the second light phase and the second heavy phase thereof;
(f) retaining the second light phase separated from the second centrifuged product and recycling the second heavy phase obtained from the second centrifuged product to fresh PUFA oil-containing fermentation broth to be directed to the first centrifuge.
2. The method of claim 1 , wherein the PUFA oil yield of the second light phase is greater than 88%.
3. The method according to claim 1 , wherein step (a) comprises the steps of:
(a1) adding the fermentation broth to a vessel;
(a2) adding a component to the fermentation broth to facilitate breaking of emulsion formation;
(a3) heating the vessel; and
(a4) pumping the fermentation broth to a first centrifuge.
4. The method of claim 3 , wherein the component in step (a2) is an enzyme or sodium hydroxide.
5. The method of claim 4 , wherein in step (a3) comprises heating the vessel to a temperature selected from the group consisting of at least 40° C., at least 50° C., at least 60° C., at least 70° C., at least 75° C., at least 80° C., at least 85° C., at least 90° C., and at least 95° C.
6. The method of claim 3 , wherein PUFA oil yield of the second light phase is greater than 88%.
7. The method of claim 6 , wherein PUFA oil yield of the second light phase is greater than 92%.
8. The method of claim 6 , wherein PUFA oil yield of the second light phase is greater than 95%.
9. The method according to claim 3 , wherein step (c) comprises the step of pumping the first light phase from the first centrifuge into the second centrifuge.
10. The method of claim 1 , wherein the process comprises repeating the steps (a)-(f) at least one time.
11. The method of claim 10 , wherein the process comprises repeating the steps (a)-(f) two more times.
12. The method of claim 10 , wherein the process comprises repeating the steps (a)-(f) three more times.