Harnessing sustainable value from seaweed
If you have ever visited a shoreline in Ireland, you have probably encountered seaweed, lying as straggled strands on the sand or flowing in forests of fronds in the water. For centuries, people in Ireland have used seaweed for fuel, food and medicine, and a new project funded by SFI is looking to harness the power of seaweed in a smart and sustainable way.
One potential use for seaweed today is to generate fuel in the form of biogas, but this may not be the most effective use of such a valuable natural resource, explains Dr Nessa O’Connor, an Associate Professor in Zoology at Trinity College Dublin.
“Seaweed grows very quickly, so it could be attractive as a source of biomass for generating biogas, but it is a lot of work to grow it just to digest it,” she says. “Our previous research showed that growing seaweed just for biogas extraction is not economically useful as a biofuel. If you want to make it economically feasible, you need to extract high value products as well as biogases.”
Dr O’Connor now leads the SFI-funded Beyond Biofuel project, which seeks to understand more about the biology of seaweed and grow it with specific products in mind. The key here, she notes, is the ‘plasticity’ of seaweed, or how it responds and adapts to its environment.
“Seaweeds are very plastic, they respond to their environment very quickly, both at the visible level - so if there is more wave action in the sea they will grow in different shapes - and at the level of their chemical properties,” says Dr O’Connor. “Our project is looking at how we might tune the molecular content of kelp by growing it under different conditions, so that it produces something that we can harvest from it as well as biomass.”
The idea is that the kelp could become a natural factory for useful compounds such as polyphenols, which are used in foods, or gels called alginates, which could be used in medical applications.
We want to be very clever about how we grow them so we can have the biochemical level change as well as the biomass,” explains Dr O’Connor. “We are looking to see if we allow snails or limpets to graze the kelp as it grows, does this boost the level of polyphenols, or if we grow it under different conditions can we increase the quantity of gel that the kelp makes.”
Growing the kelp under controlled conditions could also help to protect naturally growing seaweeds from being over-harvested for biofuels, she notes, and farming seaweed might also create more protected local environments for marine life. ‘With climate change the oceans are becoming more acidic, but seaweeds may be able to help buffer this locally,” says Dr O’Connor. “So cultivating seaweed may be another tool in our arsenal against climate change.”
The Beyond Biofuel project is working on pilot aquaculture sites for seaweed and draws on expertise around Ireland, linking in with the SFI-funded MAREI Centre at University College Cork, bioengineers in Trinity College Dublin and seaweed farmers in the west of Ireland. “We want to understand the ecology of growing seaweed, how best to cultivate it and extract those high-value products and importantly where the markets will be for these products,” says Dr O’Connor. “We want to create a circular, sustainable system where nothing gets wasted.”