Extraction of chlorophyll from wild and farmed Ulva spp. using aqueous solutions of ionic liquids

•Process to extract chlorophylls from Ulva sp.•Biomasses from two European locations were studied.•A tensioactive ionic liquid was selected as the best solvent.•The chlorophylls extracted are chemically stable. Products extracted from natural resources are an increasing trend in several fields promoted by consumer demand. Allied to the importance attached to the concept of “natural product” should be the way the “natural product” is obtained. In this work, chlorophyll was extracted from batches of wild-harvested and farm-raised green macroalgae Ulva spp. from two different European locations, Portugal and France. The performance of different aqueous solutions of tensioactive compounds such as ionic liquids and common surfactants in the yield of extraction of chlorophyll was studied and the operational conditions of extraction were optimized. The effect of drying the biomass on the yield of extraction of chlorophyll was evaluated as well as the effect of both locations (and the specific conditions of each location in terms of nutrients, water temperature and light intensity) in chlorophyll production. After optimization of all operational conditions, a maximum yield of extraction of 5.96 mgchl·gdry algae−1 was obtained using 250 mM of tributyltetradecylphosphonium chloride ([P4,4,4,14]Cl). The use of this solvent has allowed the development of a cost-effective (conclusion obtained after the economic analysis) and efficient process capable of maintaining the stability of the final product for more than one month.