Macroalgae Cultivation, Biorefinery and Application

Current Status and Future Directions

Macroalgae represent a relatively underutilised, sustainable resource and are an exceptional source of diverse compounds for use in cosmetics, pharmaceutical, food, feed, fertiliser and bio-fuel based applications.

Recently, algae experts and enthusiasts met to discuss the latest developments and future of macroalgae at two international conferences. The first of these took place in Den Helder/Texel, The Netherlands in September, entitled Seagriculture, Exploring the Seaweed Chain. As the title suggests, this event focused on materials, cultivation and harvesting, waste streams, market chain development and the seaweed biorefinery.

With almost 90% of today’s energy usage derived from the consumption of fossil fuels, renewable energy sources are highly sought after. Despite this, less than 10% of the world’s energy is derived from renewable sources (such as seaweed) and it falls well short of the target set by the EU of 20% by 2020.

Bio-fuel Challenges

During the conference, the challenges of producing biofuel were highlighted by Jaap van Hal, from the Energy Centre of the Netherlands. These challenges include the stable chemical composition of seaweeds, which renders them particularly difficult to fractionate when compared to land-based biomass. A further challenge described by Jaap is the seasonal, geographical and species-dependent variation in the chemical composition of seaweed. This variation in the protein, carbohydrate and the ash content of seaweed is further complicated by the fact that seaweed can contain up to 90% water which contributes to both transport and drying costs.

The conference nevertheless highlighted a number of facts that make seaweed an excellent choice for biofuel production. For instance, the production of biofuel from seaweed does not require land or freshwater, and therefore does not compete with food crops for these resources.

In addition, the available area for seaweed cultivation is much greater than on land as around 70% of the earth’s surface is covered with water. Furthermore, seaweed-based biofuels are produced without the need for fertilisers and pesticides which are associated with many land plants. The potential profitability and overall feasibility of biofuel production from seaweed was also discussed by experts including Sander van den Burg, researcher at Wageningen University and Machiel van Steenis, Senior Project Manager at Energy Valley.

Adequate Fractionation

The importance of adequate fractionation of macroalgae into both low and high-value product streams in order to maximise profitability was highlighted. For example, high-value products such as cosmetics can be extracted from the seaweed, while leaving behind a large amount of biomass that can be used to produce lower value products such as food/feed, and ultimately, biofuel.

Ireland was represented at the Seagriculture conference by Dr. Stefan Kraan, Co-Founder of Oceanfuel Ltd Galway, where the importance of adequate fractionation and separation of seaweed-derived compounds. In addition to producing ethanol from seaweed on a pilot scale, Oceanfuel is also developing scalable methods to extract fibre, oil, ash and protein from macroalgae.

Experts had another chance to discuss the past, present and future of algae at the 3rd Danish Algae Conference in Grenaa, Denmark in October. This conference also included a tour of AlgeCenter Denmark’s research and development plant. Here scientists are currently using specialised tanks to investigate how parameters can affect seaweed growth and composition.

Latest Developments

The conference began with presentations from the Danish Shellfish Center; Hortimare (Holland); SIOEN Industries (Belgium) and Ocean Rainforest (Faroe Islands) and went on to outline the latest developments in seaweed cultivation, integrated aquaculture, seaweed harvesting and seaweed processing.

Following a similar theme to the Seagriculture conference, the topics discussed throughout this event also included biofuel production from algae; the location and season-dependent variation in seaweed composition and methods to extract various compounds from micro and macro-algae, including beneficial Omega-3 fatty acids.

The latest developments in the utilisation of both macro and micro-algae in Iceland were outlined by Dr Hörður G. Kristinsson and Hrönn Arnardóttir from Marinox and the Blue Lagoon respectively. Like Marinox, the German company OceanBASIS also described the use of bioactive compounds that are currently extracted from brown seaweed and included in cosmetic products to provide a number of benefits, including an anti-aging effect.

Ireland was represented in Grenaa by Dr Prannie Rhatigan, a medical doctor and lifelong seaweed cook from Co. Sligo, who provided a fascinating presentation on the use of seaweed in different food recipes for healthy living. During her presentation Prannie outlined how it is possible to make healthy and tasty food using seaweed with a number of associated health benefits. The information presented at both conferences shows that macroalgae is indeed an exceptional source of diverse compounds that can be used for a wide range of applications ranging from cosmetics to fertiliser to food. It is also apparent that, despite some challenges, sustainable seaweed cultivation may help reach the EU target for renewable energy sources by 2020.

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