METHOD OF SEPARATING LIPIDS FROM A LYSED LIPIDS CONTAINING BIOMASS

Abstract

The current invention relates to a method of separating polyunsaturated fatty acids containing lipids from a lipids containing biomass.

Claims

1-16. (canceled)

17. A method of separating a polyunsaturated fatty acids (PUFAs)-containing lipid from the debris of a biomass, comprising the following steps: a) providing a suspension of a biomass comprising cells which contain a PUFAs-containing lipid; b) lysing the cells of the biomass; c) heating the suspension obtained in step b) to a temperature of 80 C. to 100 C., and adjusting the pH to a value of 9.0 to 11.5; d) maintaining the temperature and pH value in the ranges of paragraph c) for at least 10 hours.

18. The method of claim 17, wherein, in step c) the suspension obtained in step b) is heated to a temperature of 85 C. to 95 C., and the pH is adjusted to a value of 9.0 to 11.0 and in step d), the temperature and pH are maintained for a period of 20 to 36 hours.

19. The method of claim 17, wherein lysing of the cells of the biomass is carried out enzymatically, mechanically, chemically and/or physically.

20. The method of claim 19, wherein lysing of the cells of the biomass comprises: a) heating the suspension of the biomass to a temperature of between 50 C. and 70 C., adding a cell wall-degrading enzyme, and adjusting the pH to a value at which the enzyme is active; b) maintaining the temperature and pH in the ranges of paragraph a) for at least one hour.

21. The method of claim 17, wherein less than 1 wt.-%, of organic solvents and/or less than 1 wt.-%, of chloride are used in the method.

22. The method of claim 17, wherein after lysing of the cells, the suspension is concentrated to a total dry matter content of 30 to 60 wt.-%.

23. The method of claim 17, comprising as a further step the harvesting of the PUFAs containing oil.

24. The method of claim 23, wherein harvesting of the PUFAs containing oil comprises neutralizing the demulsified suspension and subsequently separating the resulting oil-containing light phase from the water, salts, residual oil and cell debris containing heavy phase and wherein separation of the oil containing light phase from the water, salt, remaining oil and cell debris containing heavy phase is realized by mechanical means at a temperature of 70-80 C. and at a pH value of 7-8.5.

25. The method of claim 24, comprising as a further step the conversion of the water, salt, residual oil and cell debris containing heavy phase into a dried biomass with a total dry matter content of more than 90 wt.-%,

26. The method of claim 25, wherein conversion into a dried biomass is carried out by concentrating the heavy phase to a dry matter content of 30-50 wt.-% and subsequently spray granulating using a fluidized bed granulator.

27. The method of claim 17, wherein the suspension is provided as a fermentation broth with a biomass density of preferably at least 80 g/l.

28. The method of claim 27, wherein the cells are selected from algae, fungi, protists, bacteria, microalgae, plant cells, and mixtures thereof.

29. The method of claim 27 wherein the cells are of the genus Schizochytrium.

30. The method of claim 20, wherein the cell-wall degrading enzyme is selected from proteases, cellulases, hemicellulases, chitinases, pectinases, sucrases, maltases, lactases, alpha-glucosidases, beta-glucosidases, amylases, lysozymes, neuraminidases, galactosidases, alpha-mannosidases, glucuronidases, hyaluronidases, pullulanases, glucocerebrosidases, galactosylceramidases, acetylgalactosaminidases, fucosidases, hexosaminidases, iduronidases, maltases-glucoamylases, beta-glucanases, mannanases, and combinations thereof.

31. A PUFAs containing biomass comprising less than 2 wt.-%, of a non-polar organic solvent and less than 2 wt.-%, of chloride, wherein the biomass contains cells and/or cell debris of the family of Thraustochytrids.

32. The PUFAs containing biomass of claim 31, comprising less than 0.1 wt.-%, of a non-polar organic solvent and wherein the biomass contains cells and/or cell debris of the genus Schizochytrium.

33. The PUFAs containing biomass of claim 31, comprising a mixture of DHA and EPA, wherein the content of DHA is at least 10 wt.-% relative to the total amount of lipid present.

34. A PUFAs containing aqueous suspension, containing a biomass, comprising a content of non-polar organic solvents of less than 1 wt.-%, and a content of chloride of less than 1 wt.-%, and wherein the aqueous suspension comprises a total dry matter content of 20 to 60 wt.-%.

35. The PUFAs containing aqueous suspension, of claim 34, comprising a content of non-polar organic solvents of less than 0.1 wt.-%.

36. The PUFAs containing aqueous suspension of claim 35 wherein said suspension comprises cells and/or cell debris of the genus Schizochytrium.

Description

WORKING EXAMPLES

Example 1

[0137] An unwashed cell broth containing microbial cells (Schizochytrium sp.) at a biomass density of over 100 g/l was heated to 60 C. in an agitated vessel. After heating up the suspension, the pH was adjusted to 7.5 by using caustic soda (50 wt.-% NaOH solution), before an alcalase (Alcalase 2.4 FG (Novozymes)) was added in liquid form in an amount of 0.5 wt.-% (by weight broth). Stirring was continued for 3 hours at 60 C. After that, the lysed cell mixture was transferred into a forced circulation evaporator (obtained from GEA, Germany) and heated to a temperature of 85 C. The mixture was concentrated in the forced circulation evaporator, until a total dry matter content of about 30 wt.-% was reached. The concentrated lysed cell mixture was transferred into a new vessel, heated up to 90 C. under low shear agitation, while adjusting the pH to 10.5 by adding caustic soda. Low shear agitation was continued for about 30 hours, while keeping the temperature at 90 C. and the pH above 9.0 by adding caustic soda.

[0138] After that the resulting demulsified mixture was neutralized by adding sulfuric acid to adjust a pH of 7.5. Phase separation into a light phase, containing the oil, and a heavy phase, containing water, cell-debris, residual oil and salts, was carried out mechanically by using a disc stack separator (Alfa Laval Disc Stack Centrifuge, LAPX 404/Clara 20)

[0139] After separation of the crude oil, the remaining cell debris were resuspended in the aqueous phase, concentrated and dried by spraygranulation.

[0140] Due to the efficient demulsification, more than 90 wt.-% of the oil could be separated from the biomass without the addition of organic solvents or sodium chloride.

[0141] The remaining heavy phase was converted into a solid biomass by concentrating via evaporation to a total dry matter of 45 wt.-% at a temperature of about 90 C. and subsequent drying via spray granulation in a fluidized bed spray granulator. The resulting biomass exhibits a high bulk density of more than 530 kg/m3, a high energy value of about 4000 kcal/kg and very good handling properties, in particular a flowability of 4. Comparable biomasses originating from Schyzochitria as available on the market exhibit all a much worse flowability of 6 and a much lower bulk density of between 325 to 500 kg/m3.