Robust cultivation of marine microalgae species for the aquaculture industry in Zeeland

Background

In the aquaculture sector algae form the first part of the life-cycle of each product. Algae are at the beginning of almost every food-chain for marine life. Land-based, controlled production of marine products such as fish and molluscs therefore requires a reliable supply of high quality micro-algae. Most companies now cultivate all the algae they require in-house as no commercially available products suit their needs. Economic margins within the aquaculture sector are generally low and therefore costs for the construction and operation of microalgae production systems should be used as efficient as possible. Although most industrial aquaculture companies have been cultivating micro-algae for some years, the costs associated to this process are not known. The species of algae used in aquaculture differ from the typical strains used in biotechnology research on algae. The limited knowledge of biological parameters of the cultivated strains (Rhodomonas, Isochrysis and Skeletonema sp.) makes it difficult to operate efficiently. This often leads to unstable cultures and rapid cell death, increasing costs. RAAQUA focusses on increasing available knowledge of the used microalgae species as well as a detailed economic analysis of the different systems used in industry.

Aim/research question

The focus is on increasing stability of the algae cultures (robustness) used in industry while aiming for highest cost efficiency.
For increased understanding of the microalgae species experimental work is performed on the growth parameters and of the used strains and the effect on the biomass quality. To assess the cost efficiency of the different reactor systems a detailed economic model of these systems will be created.

Approach

Firstly a techno economic model describing the costs associated with the production of microalgae on a small-industrial scale will be created. From a detailed costs analysis, a sensitivity analysis will determine what the most significant factors for changes in terms of costs reduction for algae production are.
Once these factors are identified experimental work will determine whether these changes could be performed on an industrial scale.
Generally techno-economic models contain many assumptions as the models describe scenarios that are not yet realized in industry. Here we work closely together with the aquaculture industry to create a model that is based on real world scenarios. Modelling work is always verified with data from project partners. Assumptions are reduced to a minimum by describing real world scenarios.
Also subject to research is the stability of the current systems in the industry. Currently operated photo bioreactors in aquaculture tend to be unstable and therefore the systems suffer from a high maintenance and downtime, significantly increasing costs. Lab scale experiments will be performed to increase understanding of the biological parameters of the used strains of microalgae. Results of the lab-scale experimental work is then tested in pilot plant scale photo bioreactors located at the HZ University of Applied Sciences, Vlissingen.
For all experimental work on lab scale the focus is the applicability on larger scale towards industrial sized operations (e.g. medium preparation, handling and sterilization methods).
As the produced biomass is used as feed in the aquaculture industry, the quality of the produced biomass is monitored during the project. Changes to growth parameters that reduce costs must still result in high quality biomass. Biomass quality for aquaculture feed is generally described using the percentage of the omega-3 fatty acids DHA and EPA (docosahexaenoic acid and eicosapentaenoic acid) of the dry weight of the algal biomass.

Partners and/or acknowledgments

The RAAQUA project is a collaboration of the Wageningen University and the HZ University of applied sciences Zeeland. All work within the project is performed at the HZ University of applied sciences, Vlissingen.

Project partners include

• AE3 Consultancy
• Algaspring
• FryMarine
• HZ University of Applied Sciences
• Imares
• LGem
• Prins & Dingemanse
• Renart Boulon
• Roem van Yerseke
• Sietec
• Smit & Smit
• Stichting Zeeschelp
• Van Antwerpen Milieutechniek
• Wageningen University