The study examines the physical and chemical description of magnesium alginate obtained from the brown alga Cystoseira barbata, existing in the coastal area of the Black Sea. We have separated a magnesium alginate by a specific method, which involves the precipitation of the alginate with an alcohol solution of magnesium chloride. The study is focused on three directions: determining the concentration of certain metals, confirming the structure of the alginate type through IR spectral analysis and the examination of the ratio of fixation of magnesium on the alginate. Results confirmed the alginate type structure as well as the presence of certain metals, among which Fe, Cd, Mn, which are to be found in the alga. The presence of Mg is to be noticed, which was fixed on the alginate during the process of obtaining the alginates. The magnesium was fixed in the ratio approximately 80% from the added magnesium quantity in the phase of precipitation of the magnesium alginate.
Proximate composition of the three green seaweeds viz., Chaetomorpha aerea, Enteromorpha intestinalis, Enteromorpha compressa one brown seaweed Dictyota dichotoma and one red seaweed Gracilaria corticata was investigated by determination of protein, carbohydrates, lipid, moisture and ash content. In the present study, the total protein was recarded upper most in E. intestinalis and bare minimum in E. compressa. The maximum carbohydrates recorded in C. aerea and minimum in G. corticata. The lipid content was acquired upper limit in E. compressa and least in C. aerea. The ash and moisture content in following of 5 different seaweeds are as follows: 7.45mg/g, 3.91mg/g were recorded in the C. aerea, 8.52mg/g, 3.42mg/g in the E. intestinalis, 8.58mg/g, 3.75mg/g in the E. compressa, 9.47mg/g, 4.23mg/g in the D. dichotoma and 6.95mg/g, 3.98mg/g in G. corticata. The proximate composition of 5 different seaweed species exhibited high nutritional value for human consumption.