Other Marine Pigments

Ask a buyer to picture a marine pigment and the answer is nearly always red. Yet seawater-grown biomass produces a far wider palette: emerald light-harvesting chlorophylls, brick-orange carotenoids, fuchsia and azure biliproteins, ink-black melanins, violet prodiginines brewed by bacteria on rotting seaweed. Each family carries its own chemistry, its own handling rules and its own assay logic — which is precisely why mixing them into one generic 'marine colour' catalogue does nobody any favours.

Eata Marisource supplies this broader palette for research and industrial use, as crude extracts, purified proteins, oleoresins and dried powders. Astaxanthin and fucoxanthin have pages of their own on this site; the pigments gathered below are everything else the ocean colours with.

A map of the palette

Before choosing a grade or a pack size, it helps to know which family you are actually shopping in, because the families barely resemble one another in behaviour:

What follows walks through the families a procurement officer is most likely to meet, with the numbers that actually change a purchase decision.

Beta-carotene from a cell that never built a wall

Dunaliella salina is the odd one out among industrial microalgae: it abandoned the rigid cell wall entirely, wrapping itself in nothing more than a plasma membrane and a thin glycocalyx. That single anatomical decision shapes everything about how its pigments are produced and sold. The alga tolerates salt concentrations high enough to pickle most other life, and under stress — intense light, high salinity, nitrogen starvation — it floods inter-thylakoid lipid globules with beta-carotene at concentrations that reach 14% of dry weight — among the highest reported for any photosynthetic organism.

Commercial culture runs on the same two-phase logic the alga itself follows: build biomass in nutrient-rich brine of moderate salinity, then shift the crop into high-salinity, high-light, nutrient-poor water to trigger carotenogenesis. Extensive operations simply let the alga colour shallow (around 20 cm) saltern ponds, where the water turns from green to a saturated salmon-orange you can see from the air. Harvesting is correspondingly gentle — no bead mill is needed to breach a wall that does not exist, so mild solvent or edible-oil extraction keeps the carotene largely all-trans. As a bonus, the same cells stockpile glycerol as an osmotic counterweight, so a Dunaliella crop is always a co-product stream rather than a single-molecule affair.

Solar salt ponds at harvest brine concentrations — the orange and red compartments owe their colour to dense Dunaliella populations.

The biliproteins: pigments that light up

Where carotenoids absorb light and quietly dissipate it, the phycobiliproteins absorb it and hand most of it straight back as fluorescence. These water-soluble proteins — the light-harvesting antennae of red algae and cyanobacteria — carry linear tetrapyrrole chromophores bonded covalently to the protein scaffold, and the result is fluorescence of a brightness and photostability that synthetic dyes struggle to match. R-phycoerythrin, the flagship, is a 240 kDa assembly of alpha, beta and gamma subunits with absorption maxima near 498 and 565 nm, emission around 573–578 nm, a molar extinction coefficient of roughly 1.96 × 10⁶ M⁻¹cm⁻¹ and a quantum yield of about 0.84. Flow cytometry panels, cell sorting and immunoassay conjugation chemistry were all built on that performance.

Purity for this family is not a vague adjective but a ratio: absorbance at the pigment maximum divided by absorbance at 280 nm. The trade recognises 0.7 as food-grade, 3.9 as reagent-grade and above 4.0 as analytical-grade material, and the purification ladder that climbs to those numbers is well understood — ammonium sulfate fractionation, ion-exchange or hydroxyapatite chromatography (which has pushed purity ratios past 6.5), ultrafiltration, and more recently membrane chromatography on salt-responsive PVDF membranes, which reaches analytical grade with reported yields of 69–82% while skipping expensive column steps altogether.

We ship this family as buffered solutions, ammonium sulfate suspensions or lyophilised powder, with the purity ratio stated on every lot and conjugation-ready material available on request.

Phycobiliprotein solution in a quartz cell emitting orange-red under blue excitation — the property that made these proteins irreplaceable in fluorescence-based instrumentation.

The greens: chlorophylls and what they become

Chlorophyll is so universal that it is easy to forget it is a product with real specifications. Marine biomass delivers the a and b forms from green algae and seaweeds, plus the c family from diatoms and brown seaweeds, and extraction is a solvent exercise — ethanol, acetone or supercritical carbon dioxide depending on how the extract will be used. The interesting chemistry starts after extraction. Drop the pH or apply heat and the central magnesium abandons the porphyrin ring, converting bright chlorophyll into olive-brown pheophytin — an outcome that ruined more than one natural-colour formulation before the industry learned to work around it. The durable answer is chlorophyllin: saponified, copper-substituted and fully water-soluble, it survives conditions that would demolish the native pigment. Between those endpoints sits a family used for colour systems, photosensitiser studies and as the sensitising layer in experimental photovoltaics, where the green pigment's ability to inject electrons into semiconductor films is the whole point.

A chlorophyll-rich extract held in a shallow glass dish — the deep green deepens toward black as concentration rises.

Ink black and bacterial colour

The darkest marine pigment comes from a defensive organ. Squid and cuttlefish ink is a suspension of eumelanin granules, typically 100–200 nm across, built from oxidised catecholamines — the same DHI and DHICA chemistry that colours human hair and skin. Eumelanin accounts for roughly 12% of the liquid ink, and once proteins and polysaccharides are stripped away by deproteinisation and solvent washing, what remains is a colloidal black solid with broad-band optical absorption, radical-scavenging behaviour and metal-chelating surface groups. Materials researchers value it for UV-shielding films that stay visibly transparent; biomedical groups study its nanoparticles for radiation protection and metal binding. Marine bacteria produce melanins too, with sponge-associated Vibrio isolates among the strongest producers reported.

Bacterial fermentation also yields the loudest colours in the catalogue. Prodigiosin — a red tripyrrole made by Hahella chejuensis, Vibrio gazogenes, Alteromonas rubra and relatives — is insoluble in water but dissolves happily in methanol or chloroform, and is famously light-sensitive; fermentation has been scaled to 200-litre bioreactors with glucose-driven productivity. Violacein, the violet counterpart from Chromobacterium and marine Pseudoalteromonas strains, has a decade of antibacterial screening literature behind it. And in the salt ponds themselves, haloarchaea synthesise bacterioruberin, a C50 carotenoid whose extra-long conjugated chain out-quenches the C40 carotenoids of photosynthetic life — optimised cultures of Halorubrum ruber have pushed production to nearly 2 mg per litre.

Cephalopod ink beside granules of the dried eumelanin pigment — the raw material of black marine coloration.

Reading a pigment certificate properly

Because these families fail in different ways, no single assay serves them all. A certificate worth its paper usually stacks several of the following:

• UV-visible spectrophotometry. The fastest identity and concentration check, but only honest when the published extinction coefficient is quoted together with the solvent and wavelength — for biliproteins the same scan should also report the purity ratio against A280.
• HPLC with diode-array detection. Separates carotenoid isomers and chlorophyll breakdown products that a single-wavelength reading lumps together; C30 phases do the heavy lifting for carotenes, and the spectral data caught by the diode array flags degradation peaks on sight.
• LC-MS confirmation. Essential territory for the bacterial pigments, where prodigiosin and its alkylated relatives have near-identical optical properties and only mass spectrometry tells them apart.
• Instrumental colour measurement. For powders and liquid lots sold on colour strength, CIELAB coordinates from a bench colorimeter track batch-to-batch drift more usefully than any subjective swatch — and the data can be trended across lots, which is where fading problems first show up.

A colorimeter reading a pigmented reference tile — the objective arbiter when colour itself is the specification.

How each colour fails

None of this is exotic. It is ordinary chemistry applied early enough — the difference between a pigment that arrives at the customer's bench performing to its literature value and one that quietly spent its potency in a warehouse.

Where these pigments are working

Test coatings of green, orange and magenta pigment films on glass — the formulation stage where colour meets its working environment.

Built to your specification

Few projects need the pigment that happens to be on the shelf. Custom work we handle routinely: Dunaliella-derived beta-carotene standardised to a chosen assay and diluted into the oil your formulation prefers; biliproteins at a specified purity ratio, in the buffer your instrument expects, or pre-activated for conjugation; chlorophyll material delivered as native extract or copper chlorophyllin depending on how acidic your system runs; eumelanin as dried powder or controlled colloidal suspension; and bacterial pigments supplied as screened research lots with identity confirmed by mass spectrometry. Pack sizes, packaging atmosphere and certificate format all follow your methods rather than ours — tell the lab what it needs and the documentation arrives already speaking its language.

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