Drugs and chemicals from aquaculture [potential products]

Aquatic organisms, especially those of marine origin, offer much interest compared to terrestrial ones with respect to drugs and secondary metabolites. Microalgae have developed metabolic pathways that lead to the accumulation of some chemicals in high quantity: carotenoids and other pigments, glycerol, proline, polysaccharides, and fatty acids. Some production of these substances occurs in open reactors with species showing special growth requirements (Dunaliella and Spirulina). A greater diversity of species, and hence of products, is likely to depend upon the operation of closed photobioreactors such as the tubular system developed and used for growing Porphyridium cruentum. Some of the significant operating parameters of this type of bioreactor are briefly described and the existing on potentiel products from microalgae reported. Some considerations about microalgae for aquaculture are also made. The world and economic contexts for macroalgae are briefly outlined and the uses of existing products (agar, carrageenan, and alginate) examined. The more numerous potentiel products are evaluated in the perspective of their present experimental uses and potentiel market, especially with respect to the pharmaceutical industry. Many of the substances identified in seaweeds show interesting properties, but widely marketed products are still to come. Although some significant efforts have been made regarding the identification and purification of biologically active substances present in invertebrates, very few success stories exist. Existing products from invertebrates are examined as well as the potentiel products and sources, which are numerous indeed. Exploitation of specific wastes (crustacean shells, for example) might be the up and coming way of obtaining useful chemicals such as carotenoids or chitin/chitosan. Although bioactive agents from invertebrates are numerous and, quite often, very potent, development of marketable products is not yet much advanced. A critical assessment of the factors involved is presented. The very few products from fish and vertebrates are also briefly considered. In conclusion, the ability of aquaculture to cope with the production of the appropriate organisms and the impact of genetic engineering are assessed