ALGAE – Management and valorisation of algae biomass discarded in aquaculture activity
Pleamar program
The general objective of the project has been to quantify, identify and characterise algae whose massive upwelling in aquaculture areas requires their removal from the environment. Based on these data, their management and alternative processes that would allow them to better exploit their potential have been evaluated, respecting the guidelines set by environmental legislation and seeking a compromise between environmental care and the economic sustainability of the aquaculture activities affected. It is part of two very different areas: the Rías Baixas of Galicia and the estuaries of Andalusia, where algae affect the cultivation of molluscs and fish, respectively.
On the one hand, ANFACO focused on the use of the protein fraction of the algae that are usually present among the biomass removed from the shellfish banks of the Rías Baixas; and on the other hand, CTAQUA valorized the algae generated in the estuaries of the South-Atlantic region of Andalusia, through a pilot trial of production of quality organic composting, made from the surplus of macroalgae from aquaculture facilities located in Esteros de Cádiz and Huelva.
Demonstration actions have been carried out on some of the proposed processes to valorise the algae removed from the environment in which aquaculture activities are carried out.
Line of action:
Marine ecosystemsStatus:
FinalizadoExecution date:
2018General Objective:
To value the biomass of algae that, due to excessive proliferation in coastal areas, puts at risk the proper exploitation of aquaculture resources in these areas.
Specific objectives:
- Quantify the algae generated as aquaculture exploitation waste in the study areas and know their destination.
- To know the characteristics of the algae removed from aquaculture farms.
- To propose, depending on the scenario identified, the possible alternatives to improve the current situation and make a viable use.
- Carry out pilot experiences to verify that the proposed recovery processes are feasible and assess their effectiveness.
- Disseminate, among the agents involved, the information obtained, the results achieved and the possibilities for improvement with respect to the initial situation.
The ALGAS project quantified the algae waste generated in Galicia and Andalusia with its subsequent sampling, identification and characterisation of algae present in four shellfish areas and in three estuaries. The predominant biomass removed has been mainly green algae of the genus Ulva and its physical-chemical characterization revealed that certain components of these algae, such as polyphenols, fatty acids, amino acids, pigments, sugars, vitamins or cytokinins, have a great potential for application. The second pilot action, developed in Andalusia, focused on obtaining quality compost, but the expected result was not obtained, as there were technical problems with the composter and the use of Ulva sp. negatively influenced the final result, so its potential application in agriculture could not be confirmed.
Two pilot actions were carried out to valorize the algae. In Galicia, the pilot experience focused on obtaining protein for animal or fish feed. This action led to the conclusion that the use of nanofiltration membranes with a smaller size, with a molecular cut-off of less than 1 kD, would facilitate the obtaining of higher concentrations of proteins. On the other hand, it was observed that a high presence of impurities in the algae biomass (cockle shells and sand) not only decreases the performance of the processes, but can also hinder the action of the mechanical elements. In the second action, the expected result was not obtained due to technical problems in the execution. In addition, the use of Ulva sp. negatively influenced the final result.
The project made it possible to highlight the value of algae biomass that, due to excessive proliferation in coastal areas, puts at risk the proper exploitation of aquaculture resources, highlighting that the macroalgae biomass associated with land-based aquaculture facilities has potential for use in the food or agricultural industry.
The results obtained have been shared with numerous aquaculture agents and represent a first approximation, with new studies being necessary to provide solutions for the recovery of algae that have a technical, environmental and economic viability.
ALGAE – Management and valorisation of algae biomass discarded in aquaculture activity
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