BR-112020002577-B1 - METHOD FOR IMPROVING THE YIELD OF DOUBLE CENTRIFUGATION FOR THE PURIFICATION OF NUTRITIVE OIL

Abstract

The present invention relates to a method of using a two-stage serial centrifugation process in the extraction of nutritive oil from a fermentation broth, this innovative method avoiding oil yield losses while preserving product quality.

Inventors

• Holger Pfeifer
• DAVID ALLEN TINSLEY
• Jochen LEBERT
• Marc BEISER
• NEIL FRANCIS LEININGER

Assignees

• EVONIK OPERATIONS GMBH
• DSM IP ASSETS B.V

Dates

Publication Date

20260317

Application Date

20180809

Priority Date

20170810

Claims (6)

1. 1. Method for improving the yield of polyunsaturated fatty acid (PUFA) oil, the method being characterized by comprising performing at least two centrifugation steps on a fermentation broth, wherein the light phase product produced after the first centrifugation step is fed to the centrifuge of the second centrifugation step, and the heavy phase product produced after the first centrifugation step is discarded, and wherein the separation cut after the first centrifugation step is made on the heavy phase side, and wherein the light phase product produced after the second centrifugation step is retained and the heavy phase product produced after the second centrifugation step is recycled into a fermentation broth that will be processed in the next processing round using said two centrifugation steps.
2. 2. A method according to claim 1, characterized by comprising the steps of: a. Adding a fermentation broth to a container; b. Adding an enzyme or sodium hydroxide; c. Heating the container; d. Pumping the fermentation broth into a first centrifuge; e. Centrifuging the mixture and discarding the heavy phase product; f. Pumping the remaining light phase into a second centrifuge; g. Centrifuging the light phase from step f and producing a new light phase and a new heavy phase; h. Retaining the oil product in the new light phase from step g) and recycling the new heavy phase and the remaining new light phase by pumping it back into a container where a new round of fermentation broth is added.
3. 3. Method according to claim 2, characterized in that, in step c), the container is heated to 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, or at least 95 °C.
4. 4. Method according to claim 2 or 3, characterized in that said steps a-h are repeated once more.
5. 5. Method according to claim 2 or 3, characterized in that said steps a-h are repeated two more times.
6. 6. Method according to claim 2 or 3, characterized in that said steps a-h are repeated three more times.

Description

CROSS-REFERENCE TO RELATED REQUESTS [0001] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62/543,659 filed August 10, 2017, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] Nutritious oils are becoming well-recognized as necessary for inclusion in a daily diet to achieve various desirable health effects. One type of nutritious oil consists of oils containing polyunsaturated fatty acids (PUFAs). The sources of these types of oils are varied and include fish, microbial sources (yeasts and algae), and possibly genetically modified plants. It is also well known that, due to the desirable unsaturation, these oils are readily oxidizable and therefore sensitive to heat and long processing times. If these oils do oxidize, the oxidation byproduct has an extremely unpleasant taste, and the product is avoided by consumers. Thus, it is desirable to use continuous or semi-continuous manufacturing processes to reduce production costs. The semi-continuous manufacturing process refers, here, to batch processing of fermentation media at the end of the fermentation process. The continuous manufacturing process here refers to the continuous processing of fermentation media, with continuous replenishment of the fermentation media that have been processed. The challenge of continuous or semi-continuous manufacturing processes, however, is to bring all the process steps together on a reasonable schedule, allowing a continuous or semi-continuous process to be used. One of the main subprocesses during a continuous or semi-continuous manufacturing process is the isolation and purification of the desired oils after they have been extracted from the oil-generating microorganisms that have been fermented and then subjected to lysis to increase the oil yield. [0003] Isolating and purifying these types of oils is challenging, since the oils are intended for human consumption and, therefore, the generation of oxidation byproducts must be reduced and the use of certain toxic additives to facilitate the isolation and purification of these oils must be avoided. [0004] Methods for isolating and purifying these types of oils are known, and in many of them, after fermentation and cell lysis, there is typically an aqueous removal step of the oil product for the purposes of product separation and purification. During the aqueous removal step, it is normal to separate the aqueous phase from the oil phase and isolate the desired final oil product while removing cell debris, digestive enzymes, and other process aids. Achieving an exact separation at the interface of two immiscible fluids is complicated, however, due to the presence of a stable emulsion that occurs due to natural emulsifiers created by the fermenting microorganisms and released during digestion and cell wall rupture. Both a yield loss problem and a low yield problem will arise. [0005] To improve oil yield, additional steps have been attempted by the oil manufacturer. However, this will substantially increase the cost of the final product. Furthermore, due to the sensitivity of nutrient oils to oxidation, the inclusion of additional processing steps will result in the oxidation of the desired oils. This oxidized oil product produces a very undesirable odor when perceived by the user. [0006] What is needed, but presumably lacking, is a manufacturing process that will have higher product yields than the current method, while still minimizing further oxidation of the final oil product and not compromising oil quality. Considering the extremely large volumes of product manufactured, each yield improvement, for example, in increments of 1%, will generate substantial savings in the manufacture of nutritive oils. SUMMARY OF THE INVENTION [0007] By using a two-stage serial centrifugation process, the dilemma of choosing between having high-quality oil but losing oil yield and having high-yield oil but losing oil quality is avoided. [0008] In a traditional single-stage centrifugation process, the final oil product is collected from the light phase after one centrifugation step. Either high-quality oil or high-yield oil is collected, but not both. For example, if high-quality oil is desired, the separation cut will be made in the light phase and thus far from the interface between the light and heavy phases. This allows some of the oil-containing fluid to be discarded with the heavy phase product, resulting in a loss of oil yield. If high oil yield is desired, the separation cut will be made in the heavy phase near the interface between the light and heavy phases in order to collect as much oil as possible. The oil collected by this method includes impurities in the isolated oil and thus impairs the oil quality. [0009] The two-stage serial centrifugation process helps to solve the above problem. After the first centrifugation stage, the separation cut is made in the heavy phase near the interface