• polysaccharides
• extraction
• enteromorpha intestinalis
• ulva
• ulva laetevirens

In the last years, many attention has been given to the algae cultivation due to their use in different field. Thus literature data concerning their cultivation and their utilization are increasing. In particular macroalgae contains high amount of carbohydrates, medium/high content of proteins, low amount of lipids as well as vitamins and aminoacids. The possible uses of algae are various and different; they can be used in both animal and human supply, in the agronomy sector, medicine, in the energy production and in the phytodepuration of water. But macroalgae are also used for the extraction of phycolloids such as carrageenans, laminarin, alginates and also ulvans.
Ulvans are a class of hetero polysaccharides content inside the vegetable cell wall of the green algae, belonging to the order of Ulvales. The composition of ulvans are extremely variable; however they are formed by xylose, ramnose and uronic acids. Like the other phycolloids, ulvans are used in the food and pharmaceutical industry for the realization of nanogels and biopolymers for capsule coating. Ulvan represents one of the easily water-soluble extractable compound belonging to the genus Ulva, and more generally from the algae of the Ulvophyceae family. In this work the attention is focused on the evaluation of the production of ulvan, extracted from two algae belonging to different genera and collected in different marine areas. In particular, alga Ulva Laetevirens, an alga from the Tyrrhenian Sea, and Enteromorpha Intestinalis, an alga from the Ligurian Sea were analyzed. Moreover other metabolites were followed during the extraction procedure, as chlorophyll, carotenoids, antocyanin , phenolic compounds, soluble proteins and sugars. Ulva Laetevirens was also cultivated in different growing condition, to investigate the role of nutrients and light to the production of metabolites and ulvan.
The analyses have been carried out on the algae and on the ulvan extracted from these.
In particular the extraction has been done on Ulva collected in march and on Enteromorpha collected in january and in may.
The data obtained show that the efficiency of extraction is higher in the algae collected in may (13% on the dry weight).
During the process of extraction metabolites such as chlorophyll, carotenoids and anthocyanins decrease in all the three type of algae. While metabolites such as phenolic compounds and antioxidant activity increase. Proteins shows a little decrease in the algal extract.
The setting up of the cultivation of Ulva involved two different aquariums: one control aquarium and one treated aquarium. In the treated aquarium have been put pollutants such as nitrates, ammonium and phosphates in order to create a condition of real environment. The cultivation has been carried out for two months, from may to june, and the pollutants have been added in two different moments (may and june).
From the analyses carried out on the algae cultivated in the aquariums chlorophyll, anthocyanins and carotenoids decrease from may to june, while polyphenols increase a little in both aquariums.
It is interesting to note that, under conditions of pollutants concentration higher, the content of sugars increase.
For this reason, algae such as Ulva and Enteromorpha, widely found in the Mediterranean, can be used in treatments called phyto purification of water. Placed at the level of industrial discharges of aquaculture plants, livestock farms, dairies and wine-making cellars, they can collect and mineralize the organic substance, after installing oxidative filters that allow the conversion of ammonia into nitrates (easily metabolizable and much less toxic). Then they can be collected for the extraction of compounds of high commercial value (ulvans). In this way not only would there be a strong reduction in pollution but also a "secondary production" linked to the trade in algae and the compounds they can obtain. The advantages of this technique are mainly related to the minimum costs that installation and maintenance would require compared to a traditional purification plant and the possibility of reusing purified water, while the only disadvantage should be sought in the request for a greater surface area than to a traditional purifier.