Phaeodactylum tricornutum - Pennate Diatom with Unique Properties

Scientific Classification

Kingdom: Chromista | Phylum: Bacillariophyta | Class: Bacillariophyceae | Order: Naviculales | Family: Phaeodactylaceae | Genus: Phaeodactylum | Species: P. tricornutum

Phaeodactylum tricornutum Profile

Phaeodactylum tricornutum represents a unique pennate (elongated) diatom measuring 15-30 micrometers in length, displaying remarkable morphological plasticity with fusiform (spindle-shaped), triradiate (three-pointed), and oval forms. This marine diatom differs from most diatoms by having lightly silicified cell walls, requiring less silicate for cultivation. Has gained significant attention in biotechnology, nutraceutical production, and marine aquaculture.

Biochemical Profile

Protein Content: 35-50% dry weight Lipid Content: 18-30% dry weight (varies with culture conditions) EPA Content: 25-40% of total fatty acids Fucoxanthin: 0.5-1.5% dry weight (very high) Chrysolaminarin: Storage polysaccharide unique to diatoms Low Silica Requirements: Minimal compared to other diatoms

Specialized Applications

EPA Production Platform: Phaeodactylum produces exceptionally high EPA concentrations, making it valuable for producing EPA-enriched copepods and rotifers. Has become model organism for studying EPA biosynthesis in microalgae.

Copepod Diet Component: Marine copepods readily consume Phaeodactylum despite elongated morphology. High EPA content makes it particularly valuable in mixed phytoplankton diets for copepod culture.

Fucoxanthin Production: The exceptionally high fucoxanthin content makes it valuable for producing this carotenoid with potential anti-obesity, anti-cancer, and antioxidant properties. Application extends beyond traditional aquaculture into nutraceutical production.

Aquaculture Biotechnology: Serves as genetic engineering platform in marine biotechnology due to available transformation protocols, complete genome sequence, and fast growth rates. Research continues into enhancing nutritional profile through genetic modification.

Cultivation Parameters

Optimal Growth Conditions:

• Salinity: 20-35 ppt, optimal 30-35 ppt
• Temperature: 18-25°C, optimal 20-22°C (64-77°F)
• pH: 7.5-8.5, optimal 8.0-8.3
• Light: 100-300 μmol photons m⁻² s⁻¹
• Silicate: Low requirements (0.2-1.0 mg/L sufficient)
• Photoperiod: Continuous light or 16:8 light:dark
• Growth Rate: Doubling time 20-30 hours

Culture Medium: Grows well in standard marine media with reduced silicate concentrations compared to other diatoms. F/2 medium, Provasoli's medium, and commercial aquaculture fertilizers all support healthy cultures.

Reef Aquarium Applications

Copepod Enrichment: Using Phaeodactylum in mixed phytoplankton diets for reef aquarium copepod cultures enhances copepod EPA content, producing more nutritious live food for reef fish that preferentially consume copepods.

Coral Nutrition: Some coral species consume Phaeodactylum cells, though elongated morphology may limit consumption by small-polyp corals. High fucoxanthin content may contribute to coral pigmentation.

Research Applications: Reef aquarium hobbyists interested in marine microbiology and phytoplankton diversity benefit from culturing Phaeodactylum as educational organism demonstrating diatom biology and morphological plasticity.

Advantages Over Other Diatoms

Reduced Silicate Demand: Low silicate requirements simplify cultivation, reducing fertilizer costs and minimizing silicate introduction into reef aquarium systems when used for copepod production.

High Lipid Production: Under nutrient stress conditions, accumulates substantial lipid reserves, making it valuable for producing lipid-enriched live food or for research into algal biofuel production.

Genetic Tools Available: Available genetic modification protocols make Phaeodactylum platform for developing designer phytoplankton strains with enhanced nutritional profiles for future aquaculture applications.