Cambridge researcher Dr Matt Davey on how algae could be used for energy, healthcare and monitoring penguins from space
If you thought algae was just sludge, think again as we venture inside The Algal Innovation Centre at Cambridge Univerity's Botanic Garden.
Disco lights shine out from within the greenhouse. But given that it’s the hottest summer solstice since 1976 on the day we visit and the temperature inside has spiralled to a stifling 38C (100F), no-one feels much like dancing.
The LED lights are there to promote the growth of algae, which you might be tempted to think of as slime. Their array of potential uses, however, makes them worthy of study.
Defying the inhospitable temperature, Dr Matt Davey bravely slips on his fetching green lab coat – it’s horticultural attire, you see – and explains more.
“The Algal Innovation Centre is a very expensive greenhouse – but it’s classified as a lab,” he says.
Built at a cost of £500,000 by the University of Cambridge, including £188,600 from a European Union project to research alternatives to fossil fuels, the centre opened at the Botanic Garden last year and is designed to take lab research to an industrial scale.
“It looks like a normal greenhouse but there are a few hidden features in here – like a sealed floor so that if there are any spills we can contain them. We have ‘swimming pools’ here where we can do scale-up experiments up to 1,000 litres,” says Matt, a senior research associate at the Department of Plant Sciences.
Since the 1970s, scientists have recognised the potential for algae to be used as a biofuel due to their oily content. But they have encountered challenges growing significant quantities and it has yet to take off.
“We have been collaborating with industry to see if we can get it to work. We now know a lot more about the algae biochemistry of it, the genetics and there were a lot of new discoveries made about the biology of the organism, so even though the industrial output didn’t take off, we advanced the science well,” says Matt. “When oil was 150 dollars per barrel it was an economically viable solution, but as the oil price crashed to 40 dollars it wasn’t worth investing in the technology to grow the algae.”
However, in June US companies ExxonMobil and Synthetic Genomics announced a breakthrough in growing genetically-modified oily algae that reignites hopes of the commercial production of biodiesel from algae, although more work is needed – see panel.
In the meantime, there is another energy option that is well advanced – and it starts by using excess nutrient run-off from farmers’ fields.
“Cambridge Water has lots of nitrate waste to deal with,” explains Matt. “We wondered whether we could take the waste and produce artificial algal blooms. It’s what we call a bio-circular economy – we take waste from one industry source, grow the algae and then do something with it such as produce methane for electricity or heat production rather than putting the nitrates back into the water supply.”
The methane production is carried out using anaerobic digestion – the same process already in use at plants around the country.
“You concentrate it down into a paste and then digest the algal cells, rotting them using enzymes, and that produces the methane. The trials carried out here show that per kilogram of algae it produces more methane compared to common agricultural leaf matter used in anaerobic digestion plants,” says Matt. “We know it performs better and the feedback from anaerobic digestion companies is even if they had it as a blend of five or 10 per cent that’s better than nothing, if you are getting the algae growing on another industry’s waste source.”
Growing sufficient quantities of algae – particularly with high oil content to create more methane – is the remaining challenge to make the process commercially viable, meaning it could still be some years before the process becomes established industrially.
But surely, given that our lakes fill naturally with the stuff, algae must be simple to grow?
“If you look at your pond and it’s green and scummy, it’s usually something different – normally it’s cyanobacteria. Historically, it’s called blue-green algae, but it’s not really algae. It’s not a species with commercial value, even though it has the trait we want to exploit, which is that it blooms very fast in warm temperatures,” says Matt.
Recreating the optimum conditions for algal growth at an industrial scale turns out to be tricky.
“Like all plants, you need enough light and nutrients. But with a bigger volume and a denser culture, you get a very dark green sludge algae bioreactor and the light will only penetrate five or 10 centimetres.
“So you need a lot of mixing. If you use a lot of artificial light, it’s expensive, so we’ve been experimenting with LED lighting for lower energy consumption.”
Air lift reactors are used at the Algal Innovation Centre to bubble air through the algae, turning it as it moves. But in addition to light for photosynthesis. algae need nutrients such as the aforementioned nitrates, along with phosphates, potassium and more – and some species need a vitamin B12 boost.
“Prof Alison Smith, my boss, works on the symbiotic relationship between bacteria that secretes vitamin B12 and the algae that will take that up. For species you can’t grow on their own, you add vitamin B12 or bacteria that makes it,” says Matt.
Algae can themselves be the source of health supplements – and the neutraceuticals market is a potentially high-value one.
“The hot topic at the moment is cod liver oil. Fish can’t produce omega-3 and omega-6 oils naturally. It’s the algae that are producing these. Sustainably, it doesn’t make sense to catch a lot of fish just to extract the oils, so why not skip that trophic level and just extract the oil from the algae in the first place?” says Matt.
“That is quite attractive in terms of sustainability for fisheries and food supply, and there is a big vegetarian and vegan market who want health food products either as an additive or in capsule form but not from an animal source.”
It's what we call a bio-circular economy ﾖ we take waste from one industry source, grow the algae and then do something with it
The benefits of oily fish in our diet – such as salmon, mackerel and sardines – were studied after researchers spotted that Eskimos had fewer heart attacks and strokes than average. The evidence of a benefit to our cardiovascular health from omega-3 is strong enough for the government to recommend that we eat at least two portions of fish a week, one of which should be oily. There is some evidence that fish oils can be good for our eyes too and reduce the risk of age-related macular degeneration, although it is less conclusive.
The research has driven a huge market for fish oil supplements. While some of these are produced from the byproducts of fishing, there are companies fishing specifically to serve this lucrative market.
There have even been stories of endangered sharks being caught for their fatty livers.
Algal oil is already available on the market as an alternative that doesn’t rely on taking more fish out of the oceans. But to enable production at higher volumes, Matt is examining how to optimise the growth conditions and nutrient supply.
“Some algae produce more oils when they are stressed. If they think they are entering a period of starvation they convert a lot of their energy into fat storage. These fats can be a convenient source of omega-3 and omega-6,” says Matt.“There is an EU programme that Cambridge is involved in looking at how the EU as a whole can sustainably source ingredients. As multinational food companies want these products, there will be a lot more emphasis on how we scale this up. There are some small companies out there doing it who are in a good position.”
Red algae are also a natural source of astaxanthin – a “more powerful anti-oxidant than vitamin C”.
The red pigment is used by salmon farms to make fish pinker.
“Wild salmon will eat red algae, which makes their flesh go pink, but on salmon farms there’s not enough algae so the flesh is grey and no-one wants to eat grey salmon,” explains Matt. “In terms of per kilogram, it’s probably one of the most expensive pigments. But organic salmon farmers don’t want synthetic pigment.
“It’s an industrial spin-off. If we can sustainably grow red algae to get the pigment in Cambridge or Scotland, that would be fantastic because at the moment it’s imported from China, so the carbon footprint is huge,” observes Matt.
It might seem easier to educate shoppers that salmon isn’t always pink, but as Matt says: “You try putting grey salmon in Waitrose...”
The study of red algae took Matt on a trip to Antarctica in 2015 – and he’ll return in January/February to continue his work.
“You get algae blooming on the snow’s surface. You get big fields of green and then they turn red – like leaves in autumn,” says Matt.
“We found that when the algae is blooming on the snow’s surface, there is vitamin B12 in the snow. When the bloom is calming down, the amount of vitamins decreased as well. This is now the forefront of our knowledge – so this is one of the reasons we’re going back. We’ll find out what come first – the vitamins or the algae.
“The snow algae bloom is right on the edge of the Antarctic areas, which are at risk of global warming. As you get more rain and they start melting earlier, it doesn’t give a chance for this ecosystem to bloom so it’s a rush to understand this before it disappears.
“One of the things we will try to work out is the amount of carbon they lock up. When they melt, they melt into rocks and the shoreline and then out into the ocean. So if you have tonnes of carbon and vitamins and nutrients being flushed in, that has to be significant.”
Scientists at the British Antarctic Survey in Cambridge have for a number of years used satellite pictures to monitor populations of penguins and other seabirds, based on their different guano ‘signatures’.
“Shrimps and krill are red because they eat the algae and when the penguins eat them and poo, it’s red everywhere – which you can see from space,” explains Matt, who will use a similar technique to examine algae. “We will be looking at satellite imagery to look at where these algal blooms are and how big they are.
“Even Scott’s early expeditions noticed these red areas. You get them in the Alps and Arctic, so another question is: ‘Are they the same species and do they have the same ecosystem impact?’.
Understanding how different strains of algae thrive in different climates could have a significant industrial benefit – and enable algae to be grown more widely.
“We can have year-round production – in summer you grow one species and in winter you grow another,” says Matt.
Progress within this intriguing greenhouse could yet have a significant impact for us all.
A breakthrough in biofuel research
Biofuel production from algae has so far failed to take off amid the challenges of producing it at industrial scale.
Developing a strain that is high in oil content and grows quickly – two essential characteristics for viable industrial oil production – has proven to be a bottleneck in the research.
But in the US in June, ExxonMobil and Synthetic Genomics announced a breakthrough in their joint research into advanced biofuels that rekindles hope.
They genetically modified an algae strain to more than double its oil content from 20 per cent to more than 40 per cent without significantly inhibiting the strain’s growth.
Unlike traditional biofuels, algae can also grow in salt water and in harsh environmental conditions, limiting stress on food and fresh water supplies.
“This key milestone in our advanced biofuels program confirms our belief that algae can be incredibly productive as a renewable energy source with a corresponding positive contribution to our environment,” said Vijay Swarup, vice president for research and development at ExxonMobil Research and Engineering Company. “Our work with Synthetic Genomics continues to be an important part of our broader research into lower-emission technologies to reduce the risk of climate change.”
The companies have been working together on producing this more sustainable and lower-emission fuel since 2009 but warn the technology is “still many years from potentially reaching the commercial market” as each element of the process needs testing to confirm that it can work at scale.
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