Algal DHA & EPA

The omega-3 ratio is written by the enzyme, not by the blender. Fish oil can only concentrate what the fish already made, but fermentation chooses the pathway first. Thraustochytrids such as Schizochytrium build docosahexaenoic acid (DHA, C22:6 n-3) through a polyketide synthase loop whose terminal product is heavily biased toward DHA, with eicosapentaenoic acid (EPA, C20:5 n-3) appearing at trace levels in traditional production strains. Nannochloropsis and the diatom Phaeodactylum tricornutum run the classical desaturase-and-elongase route instead, and their chemistry stops earlier — which is exactly why their oils pile up EPA. Two different enzymes, two different products.

Everything happens inside a closed stainless fermenter, so the oil does not depend on a fishing season, a reduction fishery or whatever the open ocean happened to carry that month. Glucose goes in, lipid-rich biomass comes out, and the oil is released by enzymatic lysis, separated by centrifugation and refined on the same unit operations the vegetable-oil industry has run for a century. Eata Marisource supplies this family across its full width: DHA-rich triglyceride oils, balanced DHA+EPA grades, EPA-forward phototrophic oils, short-path concentrates and microencapsulated powders — every lot released with a complete fatty acid profile and its own oxidation data.

Two Biosynthetic Routes, Two Product Families

PUFA-PKS strains (Schizochytrium and relatives): anaerobic polyketide synthase, energy-efficient and terminated at DHA. Commercial DHA oils from these strains typically run 35-55% DHA with EPA below 3%, which is why they dominated the first generation of omega-3 products that never touched a fish.
Next-generation fermentation strains: metabolically optimised Schizochytrium strains are reported to shift the ratio toward EPA, with emerging grades reaching roughly 20-40% EPA alongside 20-40% DHA — a profile that closes most of the historical gap between fermentation-derived and marine EPA.
Desaturase-route strains (Nannochloropsis, Phaeodactylum, Isochrysis): the classical aerobic route terminates earlier, so the oil is EPA-dominant — commonly 25-40% EPA with little DHA. Phaeodactylum additionally co-yields the carotenoid fucoxanthin, a useful second fraction from the same biomass.
Whole-biomass route: dried Schizochytrium powder carries 38-71% total lipid, for buyers who want the oil delivered with the cell wall still around it — feed trials, fermentation media and matrix applications.

Stainless steel fermentation tanks used to grow omega-3 producing microalgae.

Figure 1. Closed heterotrophic fermentation: pure-culture Schizochytrium grown on glucose before the nitrogen-limited switch into lipid storage.

What the Numbers Look Like

Grade	Typical DHA	Typical EPA	Character of the lot
DHA-rich Schizochytrium triglyceride oil	≥35% (standardised batches commonly 38–50%)	≤3%	Reference spec: acid value ≤0.5 mg KOH/g, peroxide value ≤5 meq/kg, unsaponifiables ≤3.5%, trans fats ≤1%, moisture ≤0.05%
DHA+EPA Schizochytrium oil	≥22.5% (batches often 33–35%)	≥10% (batches often 15–18%)	Fatty acid profile closer to conventional fish oil; sterol content around 1% (cholesterol and stigmasterol)
High-DHA concentrate (short-path)	50–70%	low	Molecular distillation; shipped as ethyl ester or re-esterified triglyceride on request
EPA-forward phototrophic oil (Nannochloropsis / Phaeodactylum)	<5%	25–40%	EPA-dominant; fucoxanthin-bearing fractions available from Phaeodactylum
Crypthecodinium cohnii DHA oil	~40% of total fatty acids	trace	Purity-first DHA source with a minimal EPA background

One refinement worth flagging for formulators: molecular form moves with concentration. Natural triglyceride oil keeps the fatty acids where the alga placed them; pushing past roughly 50% omega-3 requires an ethyl ester step, and re-esterified triglyceride restores the glycerol backbone afterwards. Comparative absorption work (Dyerberg et al., 2010) puts ethyl esters near 60–73% of natural triglyceride uptake without a fatty meal, with re-esterified triglyceride slightly above the natural form. We ship all three forms and state the form explicitly on the certificate, because a grade without its form is half a specification.

Glass vials filled with golden algal oil showing a range of amber depths.

Figure 2. Grades across the refining and standardisation range, from pale winterised lots to deep amber crude oil.

From Fermenter to Drum

Fermentation— pure-culture heterotrophic fed-batch growth; nitrogen limitation flips the culture from biomass production into lipid accumulation.
Release and separation— enzymatic (protease) or mechanical cell disruption releases the intracellular oil, which is then separated by centrifugation. Solvent-free routes are preferred wherever the downstream specification demands it.
Refining— degumming, bleaching and deodorisation, run gently — six double bonds do not forgive aggressive thermal loads.
Winterisation— chilled crystallisation strips saturates and waxes so the finished oil stays glass-clear in the cold.
Standardisation and stabilisation— high-oleic sunflower oil brings the DHA figure to an exact target; mixed tocopherols (typically 0.1–0.5%), ascorbyl palmitate and lecithin go in while the oil is still warm from the deodoriser.
Packaging— nitrogen-flushed containers, held cold until dispatch. Crude oil, when supplied, is stored at −18 to −13 °C with the same nitrogen discipline.

Beaker of oil chilling in an ice bath during the winterisation step.

Figure 3. Cold crystallisation during winterisation: saturates and waxes come out of solution while the omega-3 fraction stays liquid.

A Temperature Trade-off Worth Knowing

Schizochytrium negotiates with its own thermostat. Lower culture temperature stresses the chain-ending machinery in a way that raises the DHA share of total lipid, at the cost of how much lipid the cells make at all. Reported figures for the same strain read roughly like this:

Culture temperature	Total lipid in biomass	DHA share of lipids
25℃	~55%	~35%
20℃	~48%	~42%
15℃	~40%	~48%

Same organism, same vessel, three different oils. We specify the cultivation window alongside the oil, so a repeat order behaves like the first one.

Short path distillation column used to concentrate omega-3 oils.

Figure 4. Short-path molecular distillation lifts omega-3 content past 50% while keeping thermal exposure seconds short.

The Oxidation Budget

DHA carries six double bonds, and every one of them is an invitation to oxygen. The industry shorthand for that exposure is TOTOX = 2 × peroxide value + anisidine value, with voluntary monograph limits of PV ≤5 meq/kg, anisidine ≤20 and TOTOX ≤26 for finished oils. We treat the budget as a manufacturing parameter rather than a release formality: nitrogen blanketing runs from first separation to final container, antioxidants are dosed while the oil is still warm, storage stays cold, and the anisidine value is reported at batch level so secondary oxidation is visible, not averaged away.

Each lot leaves with the following on its certificate:

full FAME profile by gas chromatography — DHA, EPA, and the supporting fatty acids (myristic, palmitic, oleic, docosapentaenoic n-6) that reveal both strain and standardisation history
peroxide value, anisidine value and free fatty acids / acid value
moisture and volatiles (≤0.05%), unsaponifiable matter, trans fatty acids (≤1%)
trace elements at specification limits: arsenic, cadmium, mercury and lead around 0.1 mg/kg, copper 0.05, iron 0.2
microbiological status, including Salmonella (negative in 25 g) and Cronobacter (negative in 10 g) where the grade calls for it

Electron microscope view of spherical microencapsulated oil particles.

Figure 5. Spray-dried microcapsules under the electron microscope: the oil droplets ride inside a carbohydrate or gum matrix wall.

Forms We Ship

Form	What it is	Typical specification
Bulk refined triglyceride oil	The workhorse grade, nitrogen-flushed in drums or totes	DHA ≥35% or DHA+EPA grades, PV ≤5, cold-stored
Winterised oil	Saturates and waxes removed by chilled crystallisation	Stays glass-clear at 0 °C
High-potency concentrate	Short-path distilled, ethyl ester or re-esterified triglyceride	Omega-3 up to 70%
Microencapsulated powder	Oil droplets spray-dried into a carbohydrate or gum wall	Oil load commonly 10–50%; turns a liquid into a free-flowing powder for dry blends and protects it from oxygen
Crude algal oil	Post-separation, pre-refining, for further processing	Full trace and composition data included
Whole Schizochytrium biomass	Dried fermented powder with the lipid inside the matrix	Total lipid 38–71%

Dropper bottle releasing a single drop of golden oil onto glass.

Figure 6. The finished oil: deep amber, clear when chilled, and documented down to the last anisidine point.

Where It Goes

nutritional formulation research and ingredient development, where a documented, fish-independent DHA source simplifies both supply planning and allergen declarations
cell-culture and fermentation media work, where the oil or the whole biomass serves as a lipid and carbon co-feed
aquaculture feed trials, where Schizochytrium biomass or oil substitutes fish oil at the diet formulation stage
lipidomics, method development and analytical reference work that needs a reproducible DHA-dominant or EPA-dominant matrix
oleochemical and cosmetic formulation research, from microencapsulated powders to polar-lipid fractions

Tailored to Specification

Most of this range is made to order rather than picked from a shelf. We can select the strain family behind a target EPA:DHA ratio, standardise to an exact DHA figure, concentrate to a chosen potency, adjust the antioxidant package (tocopherol level, ascorbyl palmitate, rosemary extract), tune powder oil load and matrix, and package from grams to drums. If your application needs a QC panel beyond the standard certificate — oxidation trend over accelerated storage, sterol profile, polar lipid fraction — tell us what the data has to prove and we will build the release plan around it.

Contact us with your target grade, form and packaging, and we will come back with a specification sheet and sample support.

Catalog Number	Product Name	Order	Quantity
MLO-0010	Microalgal DHA and EPA Oil (100 Percent Vegetarian, DHA 50-92 Percent, EPA plus DHA up to 90 Percent)	Inquiry	- +

For Research or Industrial Raw Materials, Not For Personal Medical Use!