Prosea, short for 'Plant Resources of South-East Asia', is an international programme focused on South-East Asia. Its purpose is to make available the wealth of dispersed knowledge on plant resources for education, extension, research and industry through a computerized data bank and an illustrated multivolume handbook. A thorough knowledge of plant resources is essential for human life and plays a key role in ecologically balanced land-use systems. Extensive information on the plants growing in the region is needed to enable the plant resources of each country to be used optimally. A large international team of experts is preparing the texts on particular species/or genera, which are being published in commodity groups. All taxa are treated in a similar manner with details on uses, botany, ecology, agronomy or silviculture, genetic resources, breeding, prospects and literature.
This volume deals with the algae that are used in some form in South-East Asia. Their utilization falls mainly into four main categories: direct human consumption (vegetables, salads, health food), production of phycocolloids, raw material for animal feed and fertilizer, and medicinal and pharmaceutical uses. Small and unicellular algae (microalgae) are used differently from the larger ones (macroalgae). Several marine macroalgae (seaweeds) as well as a few microalgae are commercially cultured in large quantities. Among the more than 70 taxa included are vegetables such as seagrapes, purpleweed (nori) and also Spirulina and Chlorella. Important producers of phycocolloids are Betaphycus, Eucheuma and Kappaphycus for carrageenan production, Gelidium, Gelidiella and Gracilaria for the production of agar and Sargassum for alginate production. Many species of seaweeds can be used as animal feed, while microalgae often have an important role as feed for larvae of fish, crustaceans and molluscs. The use of seaweeds as fertilizer is profitable: Halimeda adds lime, while many blue-green algae can be used to enhance nitrogen fixation. Examples of medicinal and pharmaceutical uses are Acetabularia major (against gallstones) and Digenia simplex (a vermifuge).