Evaluation of low environmental impact extraction from macroalgal species in transition environments

One of the most used and remunerative applications of macroalgae is the extraction of phycocolloids, which have many uses from food to pharmaceutical application. In this context, many new species are often placed side by side to the conventional ones for extractions, especially invasive and thriving algal biomass in transitional environments. Conventional techniques for the extraction of bioactive compounds from macroalgae can be complex, as they require long times, a certain amount of solvents and energy consumption, which can be simplified through alternative techniques. The objective of this work concerns the comparison of different polysaccharide extraction techniques to evaluate yield, costs and potential environmental impact. In the present work, we evaluated the yield of the polysaccharides extracted from alien macroalgae, collected in Lake Ganzirri (Oriented Natural Reserve of Capo Peloro Lagoon, Messina) and in Venice Lagoon. The choice of the species is based on algae that produce large biomass and present invasive character. Conventional methods for the extraction of algal polysaccharides involve the use of dH2O instead of HCl. In both cases, there are several disadvantages. Maintaining water temperature (70° C) for a long period involves a high expenditure of energy and consequently an increase in production costs, especially when transferred at industrial level. Another weakness of the extraction methods is represented by the use of chemicals (HCl), which can certainly be considered an environmental risk factor due to the potential toxicity. A new method is currently being evaluated that involves the use of microwaves. This technique appears to be promising due to its "green" inspiration, but the data currently available do not allow to fully evaluate its effectiveness. In this regard, we present data on the optimization of extraction using microwaves, testing the following parameters: extraction time. working temperature, HCl vs. water as an extraction solvent. Conventional and "green" extraction methods have been compared in order to evaluate them in terms of extract yield, time and cost reduction, and environmental impact.