Method for producing a biomass which can be easily broken down and which has an increased content of polyunsaturated fatty acids
AssigneeEvonik Operations GmbH
InventorsHorst Priefert, Jens Schneider, Joachim Windau, Gabriel Závodský, Christian Rabe
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Abstract
According to the invention, it has been found that when the amount of sulfate used in the culturing of PUFAs-producing cells is selected such that the sulfate concentration drops to zero in the last phase of the growth phase of the cells, an easily disruptable biomass is obtained which has an increased proportion by mass of polyunsaturated fatty acids (PUFAs) in the final product.
Claims19
A process for producing a biomass containing polyunsaturated fatty acids (PUFAs) by fermentation, said fermentation comprising:
- a) a growth phase wherein Thraustochytriaceae cells are incubated in a fermentation medium comprising sulfate and nutrients needed for cell growth other than sulfate;
- b) an oil-production phase that begins after sulfate in the growth phase falls below 0.05 g per kg of fermentation medium and that is initiated by limiting at least one of said nutrients needed for cell growth other than sulfate;
- wherein sulfate in the fermentation medium is at a concentration that remains below 0.05 g/kg throughout the oil-production phase;
- and at the beginning of the growth phase a concentration of sulfate is present in an amount such that there is a sulfate concentration of 7.5 to 9.5 g per kg of biomass at the end of the oil-production phase.
A process for producing a biomass containing polyunsaturated fatty acids (PUFAs) by fermentation, said fermentation comprising:
- a) a growth phase wherein Thraustochytriaceae cells are incubated in a fermentation medium comprising sulfate and nutrients needed for cell growth other than sulfate wherein:
- i) the sulfate concentration at the beginning of the growth phase is chosen, at least in part, to optimize purity based on grams of docosahexaenoic acid (DHA) per kg of dry biomass in cells when an oil-production phase is complete;
- and ii) the cells are cultured in the growth phase up to a biomass density of 50 to 250 g per litre of fermentation medium;
- and b) an oil-production phase, wherein said oil-production phase begins after sulfate in the growth phase falls below 0.05 g per kg of fermentation medium and that is initiated by limiting nitrogen or phosphate;
- wherein sulfate in the fermentation medium is at a concentration that remains below 0.05 g/kg throughout the entire oil-production phase and there is a chloride content of not more than 250 mg/L during the entire fermentation;
- and at the beginning of the growth phase a concentration of sulfate is present in an amount such that there is a sulfate concentration of 7.5 to 9.5 g per kg of biomass at the end of the oil-production phase.
Dependencies are inferred from the claim text.