Marine Collagen: The New Frontier of Sustainable Beauty?

Collagen is the most abundant protein in our bodies, yet its demand far exceeds traditional production from cattle or pigs. That's why scientists are turning to the sea, a rich yet underused resource. In this article we explore how marine collagen is extracted and why it could reshape its applications. Classic techniques like acid or pepsin solubilization work but have drawbacks: they consume a lot of time, energy, and can damage the protein's structure. To overcome these limits, researchers have tested innovative methods. Ultrasound, for instance, gently breaks fibers, cutting extraction times. Deep eutectic solvents—organic compound mixtures—provide a greener environment than conventional solvents. Finally, supercritical CO₂, a gas acting like both liquid and gas, extracts collagen without toxic residues. Once obtained, collagen can be hydrolyzed into bioactive peptides: short amino‑acid chains with antioxidant, anti‑inflammatory, and even skin‑collagen‑stimulating properties. These peptides are used in cosmetics, nutraceuticals, and even biodegradable packaging, supporting a true circular economy. In short, marine collagen offers a sustainable, efficient, and versatile solution to meet the growing global demand.

Marine collagen is mainly composed of types I and III, with an amino‑acid sequence rich in glycine, proline, and hydroxyproline, which confer stability to the triple helix. Common sources include skin, scales, and bones of fish such as cod, salmon, and tuna. Traditional extraction with hydrochloric acid (pH 2‑3) breaks non‑covalent bonds but can cause uncontrolled hydrolysis, lowering the average molecular weight (MW) of collagen. Pepsin, a gastric enzyme, removes telopeptides without altering the helical structure, yielding soluble collagen (pepsin‑soluble collagen, PSC). Both methods, however, require long incubation times (12‑24 h) and large water volumes, increasing the ecological footprint.

Emerging technologies aim to optimize energy balance and product purity. Ultrasound at 20‑40 kHz generates micro‑bubble cavitation that disintegrates protein matrices, cutting extraction time to 30‑60 minutes and improving yield (up to 70% versus 40% traditionally). Deep eutectic solvents, typically a choline chloride‑glycerol mix, provide high solvating power for hydrophilic proteins while maintaining neutral pH and limiting thermal degradation. Supercritical CO₂, operating at 31.1 °C and 73.8 bar, extracts collagen under near‑isothermal conditions, preserving secondary structure and reducing solvent residues to negligible levels.

After isolation, collagen undergoes enzymatic hydrolysis (e.g., with alcalase or specific proteases) to produce peptides ranging from 2‑10 kDa. These peptides exhibit bioactivity thanks to sequences such as Gly‑Pro‑Hyp, known to stimulate fibroblast collagen synthesis and inhibit matrix metalloproteinases (MMPs). In vitro, marine peptides have shown antioxidant capacity via DPPH and ABTS assays and anti‑inflammatory activity by down‑regulating COX‑2 expression in keratinocyte cells. Cosmetic applications exploit these effects to improve skin elasticity and reduce wrinkles, while nutraceuticals target joint health and muscle regeneration. Integrating these processes into a circular value chain—from fish waste to high‑value products—creates a sustainable blue economy model, reducing reliance on terrestrial sources and mitigating the environmental impact of the collagen industry.