Spirulina

Spirulina (Arthrospira platensis and A. maxima) is a filamentous, photosynthetic cyanobacterium that thrives in alkaline, warm freshwater lakes. It is cultivated primarily as a protein‑rich dietary supplement, prized for its high content of phycocyanin, essential amino acids, and a spectrum of micronutrients that support overall human health.

• Phycocyanin: Spirulina’s major bioactive pigment, phycocyanin, is a phycobiliprotein with the molecular formula C₁₁₈H₁₈₁N₁₁₈O₂₁₁S₁₆. Its IUPAC name is (α‑β)‑phycocyanin, a tetrameric protein composed of α‑ and β‑subunits each bound to a phycocyanobilin chromophore (C₅₅H₇₀N₈O₁₈).
• Light Absorption: The pigment’s conjugated double‑bond system absorbs light at 620 nm, giving spirulina its characteristic blue‑green hue.
• Other Key Compounds: Other key compounds include β‑carotene (C₄₀H₅₆, a polyene with 11 conjugated double bonds) and γ‑linolenic acid (C₁₈H₃₀O₂, a polyunsaturated fatty acid).
• Composition: The overall dried biomass contains ~60 % protein (by weight), 7–10 % phycocyanin, 15 % carbohydrate (primarily polysaccharides), and 5–7 % lipids, of which 30 % are essential fatty acids.

• Cultivation: Commercial spirulina is cultivated in controlled, alkaline ponds (pH 9–11) in regions such as China, the United States (Hawaii, California), India, and Mexico.
• Harvesting and Drying: The algae are harvested by filtration, washed, and dried at ≤45 °C to preserve heat‑sensitive pigments. Freeze‑drying and spray‑drying are common industrial drying methods that preserve protein integrity and phycocyanin content.
• Manufacturing Practices: Quality‑focused manufacturers employ closed‑system photobioreactors to minimize contamination by toxic cyanobacteria (e.g., Microcystis) and to control nutrient composition.
• Product Certification: Certified organic and GMP‑certified products are preferred; third‑party testing for heavy metals, microcystins, and microbial load is essential for safety.
• Wild Harvesting: Wild‑harvested spirulina is rare due to environmental variability and higher contamination risk.