Eucheuma

Eucheuma is a genus of red algae (Rhodophyta) within the family Solieriaceae. It comprises several species native to tropical and subtropical coastal waters of the Indo-Pacific, where they grow on rocky substrates or are cultivated on longlines. The best-known species include Eucheuma cottonii and Eucheuma spinosum, both widely used in carrageenan production.

The primary commercial value of Eucheuma comes from carrageenan, a sulfated polysaccharide used as a thickener and gelling agent in foods, cosmetics, and other industrial products. The seaweed is harvested from wild beds or grown on ropes in mariculture operations, then processed to extract carrageenan via alkaline treatment and purification.

Taxonomy and classification: The taxonomic status of Eucheuma has been revised by phycologists, and many species traditionally placed in Eucheuma have been moved to related genera such as Kappaphycus. Both genera remain important sources of carrageenan in tropical aquaculture, and the distinction between them has implications for cultivation, management, and trade.

Ecology and cultivation: Eucheuma species favor warm, shallow, nutrient-rich waters with ample sunlight. Farming is typically conducted on suspended ropes or nets along coastlines. Cultivation cycles span several months, with harvest planning aimed at balancing yield and sustainability. Environmental considerations include habitat impact, nutrient dynamics, and resilience to climate-related changes.

Overall, Eucheuma represents a key group of carrageenan-producing red algae supporting tropical seaweed farming and the global supply of this industrial polysaccharide.