Commercial importance of marine macro algae

Abstract

India with a vast coastline of more than 8000 km supports a rich standing crop of marine algae wherever rocky or coral formations occur along the coast. The current estimate of annual standing crop of marine algae of India is 3, 01,646 tonnes (fresh weight).The algae contain minerals, trace elements (iodine and bromine), proteins, carbohydrates, lipids etc.The marine algae are a good source of organic constituents such as vitamins, bioactive substances and polysaccharides and also are useful as raw material for biofuel production and liquid fertilizer. Important polysaccharides obtained from algae are agar, carrageenan and algin. The Indian red algae such as Gelidium, Gelidiella, Pterocladia and Gracilaria yield agar and agarose. Agarose is the most important medium for electrophoresis. The red algae viz. Hypnea, Kappaphycus, Acanthophora, Laurencia are the sources of carrageenan. Algin is extracted from brown algae like Sargassum, Turbinaria, Hormophysa and Cystoseira. Mannitol is also obtainable from brown algae. This is used as a diuretic and helps in excretion of some toxins. Many of the green, brown and red algae form part of the diet taken by people of South East Asia. In India, the red alga Gracilaria edulis is eaten in certain coastal areas of Tamil Nadu as porridge. Some of the marine algal constituents are of antimicrobial, antifungal, antiviral, diuretic and spasmolytic values. The algae are used in the treatment of goiter and as ichthyotoxic compounds. Other medicinal properties and commercial uses of algae in industry and biotechnology are reviewed in this paper. Efforts must therefore be made by concerned agencies and entrepreneurs to make best use of the renewable marine algae which are available along our coasts.