In the ALEHOOP project, ANFACO is leading the processing of residual green seaweeds for the extraction of protein. The seaweeds are collected by the marine brotherhoods in Galicia (NW of Spain). This way, it is possible to avoid that the accumulation of high quantities of green seaweeds during bloom episodes, in the bivalve harvesting areas, causes the mortality of clam and cockles (Figure 1). During the project, it was calculated that between 2.000 and 3.000 tons of residual green seaweeds would be collected in the Galician Rias Baixas, each year.
Some samples of different seaweeds have been already characterized and it was concluded that, for the valorization of these biomass (via extraction of protein or polysaccharides), these seaweeds needed to be cleaned first. This is because, in many cases, the content of impurities (mainly sands and even bivalve shells) was very high. A prototype, based in the cutting of the seaweeds and flotation in a water column, due to the feeding of air microbubbles, was designed (Figure 2).
Figure 3: Different steps of the protein extraction at laboratory scale (enzymatic hydrolysis of seaweeds, membrane fractionation, spray drying and one of the products).
After having a mechanism for the cleaning process, it was time for the process for the extraction and fractionation of protein from the residual seaweeds, which was done at laboratory scale. This process was performed by using an enzymatic hydrolysis and a membrane filtration process for the separation of high molecular weight polysaccharides (Figure 3). Currently, the team is in the middle of the scaling up of the process to produce enough quantities of dry extract that will be studied in fish and animal feed assays.