Isolasi Alginat Rumput Laut Coklat (Sargassum sp.) menggunakan Jalur Kalsium Alginat

Alginate has been widely used in industrial field because of its natural properties as gelling agent. Brownseaweed, especially Sargassum and Turbinaria as the alginate sources are widely grown in Indonesia; butunfortunately there has yet to be any alginate industry in Indonesia. Alginate content in Sargassum isconsidered quite large, about 35%, whereas alginate content in Turbinaria is only around 20-25%. In thisresearch, sodium alginate was isolated from dried brown seaweed (Sargassum sp.) which first passedthrough the acid treatment using 0,5%-b/v HCl and alkaline treatment using 0,5%-b/v NaOH. Extraction wasdone in batch, using 2%-b/v Na2CO3 solvent. The chosen post-treatment method was through the Ca-alginatepath with experimental design Reponse Surface Methods-Central Composite Design with 5 center point. Thevaried variable was the concentration of CaCl2 (0,11 – 2,09 M) and the ratio of CaCl2 solution/alginateextract (0,48 – 4,02 g/g). The result showed that higher concentration of CaCl2 increased the yield, viscosity,and ash content. As the ratio of CaCl2/alginate extract got higher, the viscosity had the tendency to decreaseand the ash content increased. Yield of the obtained sodium alginate powder was 6,95 -30,7%; 1,48 – 11,85cP viscosity; ash content about 18,46 – 52,65%; and water content around 6,14 – 8,32%. The optimumcondition was obtained at CaCl2 concentration of 1,02 M and the ratio of CaCl2/alginate extract about 2,01g/g with 27,72% yield, 11,38 cP viscosity, 19,56% ash content, and 6,14-8,32% water content of sodiumalginate

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity