Transnational approaches to resolving biological bottlenecks in macroalgal biofuel production (SuBBSea)

The green macroalgae, or seaweeds, are one of the most common sights on beaches and shorelines around the UK, providing food and shelter for many marine animals. The most familiar of these green seaweeds are the Ulva species; the 'sea lettuces'. These are particularly important because they act as a link between the land and the seas; increased nutrient run-off from agricultural fertilisers, or from urban sewage treatment plants, can lead to higher nutrient levels in the rivers and seas that border farmlands and cities. These enriched waters, which can also occur naturally through the spring upwelling of nutrient-rich deeper sea waters, can, in turn, see extraordinarily rapid growth of the seaweeds that live in them; the so-called 'green tides' that can choke coastal waters worldwide and which are responsible for threatening the Olympic sailing regatta at Qingdao in 2008, covering beaches along the south coast of the UK in 2010, and fouling the Breton coast annually.

Our project aims to build on these astonishing growth rates by converting green seaweeds into fuel. We will start by using standard crop-breeding techniques (rather than genetic modification) to produce economically productive seaweed strains that can be grown safely and sustainably around the UK's coastline. Once they've been harvested, we will look at how to harness the natural processes by which seaweeds are broken down, extracting enzymes and microbes capable of converting seaweed biomass into the advanced biofuels that the UK economy will need in the years ahead.

Seaweeds are strong candidates for sustainable 2nd generation biofuels. They can be cultivated at low cost, and grow more rapidly than terrestrial plants without competing for land or water resources. Additionally, as ecosystem engineers along both the UK and Indian coastlines, they provide a number of ecosystem services that can counter the effects of wave erosion and anthropogenic stress.
SuBBSea will address its overall ambition in three broad themes:

Theme 1. GWAS approaches to macroalgal strain improvement (UK: Belfast, Bangor; India: CSMCRI): Genetic modification of seaweeds for open-water cultivation is, at present, both unacceptable and impossible. Selective breeding of seaweeds, however, has never been tried and SuBBSea represents a first application of modern breeding techniques to macroalgae. Desirable traits (e.g. growth rates, polymer composition) will be scored and Genome-Wide Association Studies will correlate traits with RADseq markers, with novel crosses generating new lines that will be tested for optimal growth.

Theme 2. NGS-driven pre-processing enzyme identification (UK: IBERS; India: CEB): Natural processes of macroalgal biomass degradation (marine grazers, microbes) will be used to inform biorefinery pre-processing strategies for the separation and extraction of structural macroalgal components. Metagenomic and functional screens of marine microbes will identify seawater-tolerant enzymes that contribute to different stages of decomposition and drive nutrient flow in coastal areas.

Theme 3. Synthetic approaches to microbial platform construction (UK: Edinburgh, India: CEB): Microbial platforms will be developed to convert the full range of seaweed-derived carbohydrates into advanced (longer-chain) biofuels, transforming known and discovered polysaccharide lyases and oligomer transporters into seawater-tolerant microbes. Biorefinery principles will determine the balance between biofuel and high value product generation.

As detailed in the Case for Support, SuBBSea will take a process view of the flow of biological material along seaweed biofuel generation pathways in the UK and India, developing: a) more productive seaweed lines for commercial and coastal management use, b) improved biocatalysts for seaweed biomass pre-processing and, c) improved biocatalysts for longer-chain biofuel generation. Accordingly, SuBBSea will be of particular benefit to the following groups:

I. Private sector - large companies (for Advanced Biofuels): The production of sustainable biofuels is obviously the subject of huge commercial investment and the green seaweeds are attracting increased interest as potential biofuel and biotechnology sources (e.g Statoil). Indian partners (ICT-CEB) already collaborate closely with IndianOil, and we will feed into this collaboration to identify synergies between bio- and thermo-chemical processing and conversion. Within the UK, partners at IBERS have strong links to the biorefinery and bioprocessing industry and further links with appropriate industrial stakeholders in the UK will be developed through the mid-term dissemination meeting in Belfast.

II. Private sector - SMEs and local enterprise (for Biotechology and low-grade biofuels): Although the green seaweeds grow abundantly in a diverse range of habitats and their mariculture as a human and animal food staple is common in Asia, their economic potential remains underexploited in UK waters. SuBBSea holds particular opportunities for SME involvement in improving low-grade, local bionergy generation (e.g. By improving pre-processing in AD) and the UK partners already have strong links with local mariculture and SMEs (e.g. B9, Deepdock Ltd, Green Biofuels Ireland, Irish Seaweeds) interested in scaling-up production plants for small-scale biofuel generation. Additionally, the green seaweeds are now attracting increased interest as potential biotechnology sources, with particular efforts being made to exploit their biofouling and bioadhesive ability, so Themes 1 and 3 of SuBBSea will be of immediate interest to biotechnology companies interested in the economic potential of algal secondary metabolites.

III. Policy makers and advisors, such as the Environment Agency, and its devolved counterparts (SEPA, NIEA): Ecosystem managers will benefit from SuBBSea's improved understanding of the ways in which seaweed cultivation may be made biosecure and, by relieving the pressures on agricultural land use, can help food security. The green seaweeds contain a number of bloom-forming ('green tides') and invasive species (a potential issue with the large-scale cultivation of any animal or crop; see Implications document); measures that are used as important indicators of estuarine quality by the EU Water Framework Directive and biosecurity by the Convention on Biological Diversity. The factors which determine whether or not particular green seaweed species will invade or bloom are thought to include sudden increases in the levels of nitrate run-off from agricultural fertilisers and sewage plants, but remain poorly understood because we do not know the extent to which seaweed behaviour is dependent on specific genetic haplotypes. The elucidation of this behaviour (= SuBBSea Theme 1) would bolster the UK's commitment to evidence-based science and agriculture policy, helping to decide how large-scale seaweed cultivation farms should be located and managed relative to onshore agriculture and industrial activity.