Green Superheroes

Micro-algae have been here on Earth for 1.2 billion years. They have a remarkable capacity to consume what we don’t want – and produce what we do want. That they do it quickly, efficiently and sustainably – makes this almost ubiquitous, highly-versatile form of microscopic life a very attractive solution for some major challenges. Nutrition and immunity support, waste-management, carbon-crusading and heavy metal remediation are all within algae’s scope. Yet many of us still see it as the green smear on damp window panes and reach for a cloth and a bottle of bleach.

“I’m particularly interested in how algae consume carbon and nutrients and respond to environmental stresses” says Professor Carole Llewellyn. “After this interview, I’m talking to a brewer about dealing with his CO₂”.

For farmers, algae can deliver a complete nutritional source for livestock – storable and non-contaminating, resistant to decomposition, portable and economic. In its hydrolysed form it strengthens immunity and can be an alternative to antibiotics. Secondly, it’s a solution for tackling excess food and farm waste – and working together these two factors combine into a formula for a sustainable circular farm economy.

Carole continues, “Within, say 5 years, we’d like to see a number of UK farmers buying-into this. We’d like to work closely with them to make it work – sustainably and commercially. We are working on a set of Decision Support Tools which integrate our pilot data, we will make this available to facilitate debate and inform decision making– but most-of-all, we’d like to build real working relationships.”

There’s already kit on the ground. ALG-AD has developed three industrial-based process facilities – one built alongside an anaerobic digestion facility in Devon, and two other sites in France and Belgium – a virtual demonstration tour is set to be open for online visitors in April. *

“Land has limited capacity to take AD digestate – so an excess nutrient problem arises, farmers are paying for its’ disposal. It’s particularly a problem in NVZs. Algae is a crop which they could be growing – valuable as an animal feed - or to develop higher value products.” Carole adds, “We’re at a stage where we understand the production process and the product. There’s an immense appetite to further identify and nurture markets. Solutions here will let the whole project take-off under its own momentum. Pharma’, cosmetics, feeds, bio-stimulants – we’re looking at them all, and we have expertise in quite a few of those. Bio-stimulants is an interesting area: this is about providing specific minerals and organic compounds in an accessible form for growth in some specific plants.”

Dr Alla Silkina explains the process on-the-ground. “The Devon algal cultivation facility is linked to a dairy farm and AD plant. Here, we installed 7,000 litre photo-bioreactors, two membrane filtration rigs, and several tanks. Unwanted AD digestate is stored in a preparation tank before filtration to reduce it to a less dense solution. As the digestate is very thick, we further dilute to 2.5 per cent and use this to cultivate the algae. The culture is grown in the photo-bioreactor for 2-3 weeks. Up to 50 per cent of this culture is then harvested and filtered – before entering a secondary photo bio-reaction process. Here we’re accelerating the reaction – doubling it - by adding more energy in the form of sugars.

“From 1 tonne of prepared digestate, we can currently produce up to 200 kilogrammes of dry algal biomass. This quantity depends on the nitrogen and phosphorus in the digestate. The resulting biomass is being further formulated to make animal feed. When you are extracting higher value compounds from the algal biomass, this becomes an even more attractive economic proposition. To achieve that higher value we’ve been studying the biochemistry of the cells breaking down macro-molecules (using hydrolysation) to produce higher-value different compounds for speciality feeds, for example, peptides from proteins.”

Alla continues, “A farmer would need the three basic components: tanks, reactors - the transparent polycarbonate tubes with a pump and control system to feed and agitate the algae – and a filtration harvesting system. In terms of area required for the plant, a former silage clamp would be ideal.”

“We’re developing a whole new area of agriculture in a short time-space here!” Carole says. “Just think how long it’s taken to develop growing systems for today’s farm-products! We’ve passed proof-of-concept on a large scale,” Carole concedes, “Yes, we can do better: we’d like to be consuming more digestate in the process, for example. But that gives us something to aim for! We’re looking at process-plant development with our Swansea University engineering department, and we’re looking at alternative, cheaper open systems or “raceways.” It’s an exciting project: the potential’s enormous!”

*For further information visit: https://www.nweurope.eu/projects/project-search/alg-ad-creating-value-from-waste-nutrients-by-integrating-algal-and-anaerobic-digestion-technology/

For further information contact: Professor Carole Llewellyn at c.a.llewellyn@swansea.ac.uk or Dr Alla Silkina at a.silkina@swansea.ac.uk