Process for enriching the biomass of microalgae of the thraustochytrium genus with dha and with arg and glu amino acids
AssigneeRoquette Freres
InventorBernard Caulier
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Abstract
The present invention relates to a process for enriching a biomass of microalgae of the Thraustochytrium genus with DHA and with arginine and glutamic acid amino acids, characterized in that it comprises a step aimed at limiting the rate of growth of the microalga while at the same time maintaining or continuously introducing a source of nitrogen in or into the fermentation medium.
Claims13
1- A process for enriching a biomass of microalgae of the Thraustochytrium genus with docosahexaenoic acid (DHA) and with arginine and glutamic acid amino acids, comprising limiting the growth rate of the microalga in a fermentation medium, determining a ratio of growth rates μ/μmax of the microalgae, concurrently with said limiting maintaining or continuously introducing a nitrogen source in or into the fermentation medium as soon as the value of the ratio of the growth rates μ/μmax of the microalgae becomes less than 0.2, to produce a biomass.
2- The process according to claim 1, wherein the microalgae are of the genus Schizochytrium sp. or Schizochytrium mangrovei genus.
3- The process according to claim 1, wherein the microalgae are a strain selected from strain references CNCM I-4469 and CNCM I-4702 deposited with the Collection Nationale de Cultures de Microorganismes [French National Collection of Microorganism Cultures] of the Institut Pasteur on Apr. 14, 2011 and Nov. 22, 2012, respectively.
4- The process according to claim 1, wherein the limitation of the growth rate of the microalga is obtained by reducing or exhausting trace elements in the fermentation medium or by limiting the O2 transfer.
5- The process it according to claim 1, further comprising harvesting the biomass, optionally preparing a cell extract or lysate from this biomass, and then optionally extracting a DHA-rich crude oil.
6- The process according to claim 1, wherein the biomass obtained comprises at least 45% of DHA by weight of total fatty acids.
7- The process according to claim 1, wherein the biomass obtained comprises at least 40% of proteins by weight of biomass (g/g) expressed in N.6.25, including at least 10% of arginine and at least 25% of glutamic acid by weight relative to total amino acids.
8- A process for producing a biomass, comprising,
- culturing microalgae of genus Thraustochytrium in a fermentation medium to enrich docosahexaenoic acid (DHA), arginine and glutamic acid amino acid content,
- feeding a source of nitrogen to the medium,
- assessing μ/μmax during said culturing, wherein μ is the actual growth rate of the microalga and μmax is the is optimal growth rate of the microalgae,
- maintaining or adding said nitrogen source to the fermentation medium when μ/μmax of the microalgae becomes less than 0.2,
- optionally, controlling the supply oxygen to the fermentation medium such that μ drops to μ/μmax <0.2 rapidly, and
- recovering a biomass, including at least 10% of arginine and at least 25% of glutamic acid by weight relative to total amino acid content.
9- The process according to claim 8, wherein the microalgae is one of Schizochytrium sp. Strain CNCM I-4469, or Schizochytrium mangrovei strain CNCM I-4702.
10- The process according to claim 1, wherein the biomass includes at least 25% of DHA by weight of total fatty acids.
11- The process according to claim 9, wherein the biomass includes at least 45% of DHA by weight of total fatty acids.
12- The process according to claim 1, wherein the biomass includes at 15% of arginine and at least 40% of glutamic acid.
13- The process according to claim 9, wherein the biomass includes at 15% of arginine and at least 40% of glutamic acid.