As a child in the mid-1960s, I spent my days living an idyllic country life on a dairy farm in the village of Lewdown in central Devon. I recall many happy days exploring the glorious countryside, living a life in balance with nature and the environment – or at least, that's how I feel.
But I also remember the always-filled mud pit at the end of our barn. It's not fenced off, and my mother constantly reminds me that getting lost too close can mean drowning in what is essentially a giant bucket full of stinking cow dung. As a five-year-old, I'm still clear.
What we didn't know was that this farmyard manure pit was not only dangerous to me but also to our environment. Manure, which is often returned to the soil as a nutritious fertilizer without taking into account its broader effects, releases greenhouse gases including methane, carbon dioxide and nitrous oxide as well as other gases. other harmful nitrogen such as ammonia. It can also lead to nitrogen-rich runoff into water bodies, polluting rivers, lakes and coastlines – with a knock-on effect on fish mortality and tourism.
In short, what I thought was an idyllic childhood, living on a farm in balance with nature, was not quite so. Then, as a biologist, I spent most of my life studying microorganisms that can help maintain a healthy planet. Nearly 60 years later, I find myself leading a pioneering Europe-wide project dedicated to turning potentially harmful waste into something positive. In the process, we can help build a “circular economy” that regenerates nature and keeps materials in circulation. And at the heart of this work are some remarkable microscopic creatures – our “green gold”.
Nature's Gems
We all know how important trees are to carbon sequestration, but we tend to overlook two-thirds of our planet being covered by water. Our seas and oceans are filled with organisms that are equally important to the Earth's life cycle, but because they are harder to see with the naked eye than land plants, we largely ignore them. through them.
Microalgae - not to be confused with macroalgae (seaweed) - abound in our freshwater seas, lakes and rivers. These tiny organisms are important "primary producers" on our planet, acting as biomass production plants. They use sunlight through photosynthesis to convert inorganic molecules (carbon dioxide, nutrients, and water) into proteins, fats, and carbohydrates, along with a host of other organic compounds that help they grow and survive. These tiny microorganisms support all life in our oceans, and with their high turnover rates, they contribute to about 50% of the planet's primary production.
There are literally hundreds of thousands of species of microalgae. One commonly occurring group is the diatoms, of which there are an estimated 20,000 species. With beautifully intricate, snowflake-like cell walls made of glass, diatoms are nature's true gems. Another common group are the coccolithophores, which are covered with intricate, saucer-like plates of calcium carbonate. During the Cretaceous period, which ended 66 million years ago, huge flowers of coccolithophores formed the white cliffs of Dover.
Since microalgae have no roots, leaves and stems, they can use carbon dioxide and nutrients more efficiently than terrestrial plants, allowing them to grow faster. They can be grown and harvested relatively easily to produce biomass crops (“algae farming”) that can be used for food or bioenergy. Algae biomass also contains a wide variety of useful molecules that can be used in bioplastics, biofuels, health products, cosmetics and food ingredients.
My growing appreciation for these fascinating microorganisms, with their amazing ability to grow on wasted nutrients and produce something useful, has inspired I want to help address the dual global challenges of sustainability and environmental protection. To me, using nature's "green gold" to clean up excess nutrients while also producing sustainable animal feed and other products seems indisputable.
Back in the 70s, I recall my A-level biology teacher, Mr. Montague, introducing us to the carbon and nitrogen cycles and explaining the importance of the balance of each of these cycles. for life on our planet. I even remember him talking about the greenhouse effect and rising temperatures. But we didn't realize then how severe the threat of climate change related to carbon dioxide - or nitrogen - would emerge as a major contributor to the complex environmental challenges we face. face today.
Towards a circular economy
To have any hope of achieving global climate change goals and achieving a sustainable equilibrium, we need to move towards a circular economy that eliminates waste and pollution, maintains circulation. materials and natural reproduction. This must replace our current linear “use and discard” model, which has resulted in unbalanced nutrient cycles.
To address this, farmers, the food industry, and wastewater companies are increasingly turning to anaerobic digestion (AD) to treat their waste. AD is a natural process in which bacteria in large pools known as digesters feed on organic waste - wastewater, food waste, farm manure and other agricultural waste - to produce biogas. science, rich in carbon and hydrogen, can be captured and used to generate renewable electricity and heat.
The nitrogen component of organic waste is retained in a thick liquid called digesta, which can be returned to the soil by farmers as a naturally produced fertilizer – better than synthetically produced fertilizers. produced by energy-intensive and CO₂-emitting processes. However, as the AD industry has expanded, so has increased yields and the return of digestibles to the soil with the risk of nutrient contamination.
As a result, many areas in the UK and Europe are currently restricted by the Nitrate Directive and the nitrate vulnerable zone (NVZ) law, introduced to prevent pollution from excessive nitrogen use. back to the land. Currently, 55% of land in England is designated as an NVZ, while the whole of Wales is in the process of becoming one.
One way to overcome this regulatory challenge is to use microalgae. And so, in 2017, our Europe-wide circular economy project called ALG-AD was born. The ultimate goal is to convert nitrogen that poses environmental risks into microalgae that can be used in sustainable animal feeds, replacing existing resource-intensive feed sources in the process. Using funding from the INTERREG North West Europe program, Swansea University has partnered with ten other institutions across North West Europe – an agriculturally densely populated region and particularly vulnerable to nitrate pollution. in groundwater. All of Belgium, Germany, the Netherlands and Denmark have also been designated as NVZs.
By recycling unwanted nitrogen into something useful, we can prevent it from escaping into the atmosphere and into water bodies, thereby reducing pollution to both the soil and the atmosphere. Microalgae naturally convert nitrogen into proteins and other nutrient molecules that can be used back up the food chain. Five years since the project's launch, we have proven that such a circular economy solution is possible on an industrial scale.
A new source of protein
The projected growth of the planet's population over the next half century means that global food production is expected to increase by at least 50%. We are also encouraged to reduce meat protein consumption to reduce greenhouse gas emissions and deforestation. Therefore, new sources of protein are the priority and microalgae are strong competitors. Companies like Nestlé have studied microalgae as an alternative source of protein, both as animal feed and as food for humans.
While the microalgae production industry is still in its infancy, the possibility of producing a new source of protein without the problems associated with meat and soy is intriguing. Furthermore, being able to grow microalgae close to where they will be used by farmers as animal feed offers a distinct advantage.
A major challenge for our European project was testing this technology for development at full operational scale. We have therefore worked directly with the AD industry as it processes food and farm waste, providing us with industrially produced nitrogen (in digestibles) for microalgae farming. ours.
Algal 7,000 L photobioreactor, built in a heated greenhouse at Langage-AD in Devon. Photo: Claudio Fuentes- Grünwald, Author provided
In the UK, just 30 miles from the Devon farm where I lived as a child, we built an “algae-AD” test facility at an AD company located next to Langage Dairy Farms. Langage-AD has the capacity to process 20,000 tons of food waste per year, generating bio-methane to generate heat and electricity. We were provided with a large, heated greenhouse located right next to the waste disposal site. This is the ideal location for our “algae photobioreactor”, a series of transparent vertical tubes in which microalgae are grown in nutrient-rich water exposed to even light. daylight and artificial light.
Two sister photobioreactors have been built in Brittany in France and Ghent in Belgium. All partners have carried out in-depth studies to determine the best way to process digesta and optimize nutrient absorption. Too much and we find that our microalgae don't like it; too little and not much happens.
Algae farming facility in Langage-AD.
Promisingly, we have found that microalgae grown on protein-rich digesters than microalgae grown on more commonly used inorganic nutrients, with protein levels up to approx. 80% of the total biomass is generated. This is more than double the amount of protein found in meat and soy products. In a world where protein shortages are on the rise and people are looking for alternatives to meat, this is a real bonus.
Currently, about 75% of world soybean production is used as a source of protein in animal feed. As with beef production, soybean production has come under scrutiny for its role in deforestation, particularly in Brazil and Argentina. In addition, shipping soybeans around the globe creates a huge carbon footprint. On top of that, shipping soybeans to highly agricultural areas disturbs the global nitrogen balance, leading to "nutrient hotspots" and an increase in NVZ.
Our studies confirmed the potential of microalgae as a protein source to supplement and replace soy protein. However, the scale of microalgae farming is not yet large enough to make a significant impact on the soybean market. Therefore, our field feed trials to date have focused on testing microalgae as a food supplement, to improve the health of piglets and fish. But we know that the market for algae-based feed and ingredients will grow rapidly.
Deploy these new biotechnologies
So far in the UK we have focused on two common freshwater green microalgae, Chlorella vulgaris and Scenedesmus obliquus (both in the phylum Chlorophyta). Both species contain good levels of protein and a host of molecules with health-promoting properties that we are still discovering.
But another great thing about microalgae is their diversity. There are tens of thousands of other species, with many spectacular shapes and functions, still waiting to be discovered.
Now, backed by our research platform, pioneers, regulators and investors must work together to enable wider deployment of these new biotechnologies. As we transition to a more circular society and economy that uses waste while preventing pollution, it seems likely that microalgae will become more familiar to all of us in the form of one form or another.
Our project has demonstrated that microalgae have a strong potential to help reduce problems related to food security such as soil scarcity, climate change and inefficient and unsustainable use of fertilizers. sustainability, as well as nutrient leakage and water pollution. In doing so, they can be used to raise environmental standards in Europe and around the world. Indeed, our work supports the recently announced European Green Deal, promoting the circular economy and protecting nature, as well as the New Common Agricultural Policy with an emphasis on methods Eco-friendly farming and agro-ecology.
For the period 2023-27, the Common Agricultural Policy (CAP) will be built around these 10 key goals. EC
However, it is still relatively early days. As with any waste-related technology, laws and regulations need to be carefully considered. Currently, the simplest way is to use anaerobically digested plant waste instead of animal waste, thus eliminating the possibility of any animal waste or animal contamination coming back into the chain. food.
We also wanted to further enhance the uptake of digesta by algae, and like any new and developing technology, we needed to balance the costs and the overall environmental benefits. To this end, we are collecting results from the entire partnership and consolidating our data for use in lifecycle analytics. This will also allow farmers, food producers and other interested industries to decide if the technology is for them and what they can best achieve according to their specific needs. mine.
Another way that microalgae can be used to aid in agriculture is as biostimulants – natural products that, when used in small amounts, enhance nutrient uptake and improve yield. stress tolerance, thus reducing the need for chemical fertilizers. We are also doing further research on many other valuable components in microalgae cells, including beneficial molecules such as human and animal immune modulators, anti-inflammatory and anti-inflammatory drugs. virus. The full benefits of microalgae for the production of new products are just waiting to be reaped.
Ironically, during my working life, I hadn't really heeded my mother's advice years ago to stay away from the dangerous mix of nutrients that smelt in the manure pit at the bottom of the barn. our cow. But I like to think that, by not doing so, I was part of a revolution in the way we value and treat waste, ensuring that the valuable nutrients in cow manure and organic waste are More and more opportunities can be used for our benefit. , and our planet.
