Gracilaria gracilis, Source of Agar: A Short Review

Marine organisms represent an enormous reservoir of compounds with many potential applications. Microbes, vegetals and animals from the sea have been exploited for numerous purposes. From seaweeds, in particular, many active compounds can be obtained, such as three important phycocolloids: agar, carrageenan and algin. In this report, an overview is given about biological characteristics, cultivation, agar and bioactive molecules content of the Rhodophyta Gracilaria gracilis; also, agar extraction processes and its traditional and innovative applications are discussed. Cultivation of G. gracilis is subject of several studies and experiments, because there is still much to understand for improving productivity and biomass yield. G. gracilis is one of the best candidates for cultivation and consequent agar extraction, thanks to: fast growth rate, ease of vegetative reproduction, good resistance to salinity and temperature oscillation, good agar qualities. The possibility of farming G. gracilis opens positive perspectives if some factors are taken into account: constant availability of raw material for agar extraction and preservation of ecological balances in natural environments. Agar extraction methods have been also reviewed in terms of improvement related to both agar yield and agar gel strength. As widely acknowledged, the main uses of agar are related to formation of thermoreversible gels at low concentrations in water. It exhibits also many beneficial biological activities including anticoagulant, antiviral, antioxidative, anticancer and immune- modulating activities. Newest applications of agar in pharmaceutical, medical, engineering and other fields are of great interest and are the topic of current and future studies.