̽��ֱ�� of Cambridge - photosynthesis

Driving on sunshine: clean, usable liquid fuels made from solar power

sc604 — Thu, 18 May 2023 15:01:02 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, harnessed the power of photosynthesis to convert CO2, water and sunlight into multicarbon fuels – ethanol and propanol – in a single step. These fuels have a high energy density and can be easily stored or transported.

Unlike fossil fuels, these solar fuels produce net-zero carbon emissions and are completely renewable, and unlike most bioethanol, they do not divert any agricultural land away from food production.

While the technology is still at laboratory scale, the researchers say their ‘artificial leaves’ are an important step in the transition away from a fossil fuel-based economy. ̽��ֱ��results are reported in the journal Nature Energy.

Bioethanol is touted as a cleaner alternative to petrol, since it is made from plants instead of fossil fuels. Most cars and trucks on the road today run on petrol containing up to 10% ethanol (E10 fuel). ̽��ֱ��United States is the world’s largest bioethanol producer: according to the U.S. Department of Agriculture, almost 45% of all corn grown in the US is used for ethanol production.

“Biofuels like ethanol are a controversial technology, not least because they take up agricultural land that could be used to grow food instead,” said Professor Erwin Reisner, who led the research.

For several years, Reisner’s research group, based in the Yusuf Hamied Department of Chemistry, has been developing sustainable, zero-carbon fuels inspired by photosynthesis – the process by which plants convert sunlight into food – using artificial leaves.

To date, these artificial leaves have only been able to make simple chemicals, such as syngas, a mixture of hydrogen and carbon monoxide that is used to produce fuels, pharmaceuticals, plastics and fertilisers. But to make the technology more practical, it would need to be able to produce more complex chemicals directly in a single solar-powered step.

Now, the artificial leaf can directly produce clean ethanol and propanol without the need for the intermediary step of producing syngas.

̽��ֱ��researchers developed a copper and palladium-based catalyst. ̽��ֱ��catalyst was optimised in a way that allowed the artificial leaf to produce more complex chemicals, specifically the multicarbon alcohols ethanol and n-propanol. Both alcohols are high energy density fuels that can be easily transported and stored.

Other scientists have been able to produce similar chemicals using electrical power, but this is the first time that such complex chemicals have been produced with an artificial leaf using only the energy from the Sun.

“Shining sunlight on the artificial leaves and getting liquid fuel from carbon dioxide and water is an amazing bit of chemistry,” said Dr Motiar Rahaman, the paper’s first author. “Normally, when you try to convert CO2 into another chemical product using an artificial leaf device, you almost always get carbon monoxide or syngas, but here, we’ve been able to produce a practical liquid fuel just using the power of the Sun. It’s an exciting advance that opens up whole new avenues in our work.”

At present, the device is a proof of concept and shows only modest efficiency. ̽��ֱ��researchers are working to optimise the light absorbers so that they can better absorb sunlight and optimising the catalyst so it can convert more sunlight into fuel. Further work will also be required to make the device scalable so that it can produce large volumes of fuel.

“Even though there’s still work to be done, we’ve shown what these artificial leaves are capable of doing,” said Reisner. “It’s important to show that we can go beyond the simplest molecules and make things that are directly useful as we transition away from fossil fuels.”

̽��ֱ��research was supported in part by the European Commission Marie Skłodowska-Curie Fellowship, the Cambridge Trust, and the Winton Programme for the Physics of Sustainability. Erwin Reisner is a Fellow and Motiar Rahaman is a Research Associate of St John’s College, Cambridge.

Reference:
Motiar Rahaman et al. ‘Solar-driven liquid multi-carbon fuel production using a standalone perovskite-BiVO4 artificial leaf.’ Nature Energy (2023). DOI: 10.1038/s41560-023-01262-3

For more information on energy-related research in Cambridge, please visit Energy IRC, which brings together Cambridge’s research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.

Researchers have developed a solar-powered technology that converts carbon dioxide and water into liquid fuels that can be added directly to a car’s engine as drop-in fuel.

Shining sunlight on the artificial leaves and getting liquid fuel from carbon dioxide and water is an amazing bit of chemistry

Motiar Rahaman

A photoreactor with an artificial leaf working under solar irradiation.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Photosynthesis ‘hack’ could lead to new ways of generating renewable energy

sc604 — Wed, 22 Mar 2023 15:57:53 +0000

Researchers have ‘hacked’ the earliest stages of photosynthesis, the natural machine that powers the vast majority of life on Earth, and discovered new ways to extract energy from the process, a finding that could lead to new ways of generating clean fuel and renewable energy.

Floating ‘artificial leaves’ ride the wave of clean fuel production

sc604 — Wed, 17 Aug 2022 14:58:44 +0000

Researchers have developed floating ‘artificial leaves’ that generate clean fuels from sunlight and water, and could eventually operate on a large scale at sea.

Wireless device makes clean fuel from sunlight, CO2 and water

sc604 — Mon, 24 Aug 2020 15:00:00 +0000

̽��ֱ��device, developed by a team from the ̽��ֱ�� of Cambridge, is a significant step toward achieving artificial photosynthesis – a process mimicking the ability of plants to convert sunlight into energy. It is based on an advanced ‘photosheet’ technology and converts sunlight, carbon dioxide and water into oxygen and formic acid – a storable fuel that can be either be used directly or be converted into hydrogen.

̽��ֱ��results, reported in the journal Nature Energy, represent a new method for the conversion of carbon dioxide into clean fuels. ̽��ֱ��wireless device could be scaled up and used on energy ‘farms’ similar to solar farms, producing clean fuel using sunlight and water.

Harvesting solar energy to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and transition away from fossil fuels. However, it is challenging to produce these clean fuels without unwanted by-products.

“It’s been difficult to achieve artificial photosynthesis with a high degree of selectivity, so that you’re converting as much of the sunlight as possible into the fuel you want, rather than be left with a lot of waste,” said first author Dr Qian Wang from Cambridge’s Department of Chemistry.

“In addition, storage of gaseous fuels and separation of by-products can be complicated – we want to get to the point where we can cleanly produce a liquid fuel that can also be easily stored and transported,” said Professor Erwin Reisner, the paper’s senior author.

In 2019, researchers from Reisner’s group developed a solar reactor based on an ‘artificial leaf’ design, which also uses sunlight, carbon dioxide and water to produce a fuel, known as syngas. ̽��ֱ��new technology looks and behaves quite similarly to the artificial leaf but works in a different way and produces formic acid.

While the artificial leaf used components from solar cells, the new device doesn’t require these components and relies solely on photocatalysts embedded on a sheet to produce a so-called photocatalyst sheet. ̽��ֱ��sheets are made up of semiconductor powders, which can be prepared in large quantities easily and cost-effectively.

In addition, this new technology is more robust and produces clean fuel that is easier to store and shows potential for producing fuel products at scale. ̽��ֱ��test unit is 20 square centimetres in size, but the researchers say that it should be relatively straightforward to scale it up to several square metres. In addition, the formic acid can be accumulated in solution, and be chemically converted into different types of fuel.

“We were surprised how well it worked in terms of its selectivity – it produced almost no by-products,” said Wang. “Sometimes things don’t work as well as you expected, but this was a rare case where it actually worked better.”

̽��ֱ��carbon-dioxide converting cobalt-based catalyst is easy to make and relatively stable. While this technology will be easier to scale up than the artificial leaf, the efficiencies still need to be improved before any commercial deployment can be considered. ̽��ֱ��researchers are experimenting with a range of different catalysts to improve both stability and efficiency.

̽��ֱ��current results were obtained in collaboration with the team of Professor Kazunari Domen from the ̽��ֱ�� of Tokyo, a co-author of the study.

̽��ֱ��researchers are now working to further optimise the system and improve efficiency. Additionally, they are exploring other catalysts for using on the device to get different solar fuels.

“We hope this technology will pave the way toward sustainable and practical solar fuel production,” said Reisner.

Reference:
Qian Wang et al. ‘Molecularly engineered photocatalyst sheet for scalable solar formate production from carbon dioxide and water.’ Nature Energy (2020). DOI: 10.1038/s41560-020-0678-6

A bold response to the world’s greatest challenge
̽��ֱ�� ̽��ֱ�� of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the ̽��ֱ��’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

Researchers have developed a standalone device that converts sunlight, carbon dioxide and water into a carbon-neutral fuel, without requiring any additional components or electricity.

We hope this technology will pave the way toward sustainable and practical solar fuel production

Erwin Reisner

Dr Qian Wang

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Scientists pioneer a new way to turn sunlight into fuel

hll43 — Mon, 03 Sep 2018 15:00:00 +0000

Photosynthesis is the process plants use to convert sunlight into energy. Oxygen is produced as a by-product of photosynthesis when the water absorbed by plants is ‘split’. It is one of the most important reactions on the planet because it is the source of nearly all of the world’s oxygen. Hydrogen which is produced when the water is split could potentially be a green and unlimited source of renewable energy.

A new study, led by academics at the ̽��ֱ�� of Cambridge, used semi-artificial photosynthesis to explore new ways to produce and store solar energy. They used natural sunlight to convert water into hydrogen and oxygen using a mixture of biological components and manmade technologies.

̽��ֱ��research could now be used to revolutionise the systems used for renewable energy production. A new paper, published in Nature Energy, outlines how academics at the Reisner Laboratory in Cambridge's Department of Chemistry developed their platform to achieve unassisted solar-driven water-splitting.

Their method also managed to absorb more solar light than natural photosynthesis.

Katarzyna Sokół, first author and PhD student at St John’s College, said: “Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store.”

Artificial photosynthesis has been around for decades but it has not yet been successfully used to create renewable energy because it relies on the use of catalysts, which are often expensive and toxic. This means it can’t yet be used to scale up findings to an industrial level.

̽��ֱ��Cambridge research is part of the emerging field of semi-artificial photosynthesis which aims to overcome the limitations of fully artificial photosynthesis by using enzymes to create the desired reaction.

Sokół and the team of researchers not only improved on the amount of energy produced and stored, they managed to reactivate a process in the algae that has been dormant for millennia.

She explained: “Hydrogenase is an enzyme present in algae that is capable of reducing protons into hydrogen. During evolution, this process has been deactivated because it wasn’t necessary for survival but we successfully managed to bypass the inactivity to achieve the reaction we wanted – splitting water into hydrogen and oxygen.”

Sokół hopes the findings will enable new innovative model systems for solar energy conversion to be developed.

She added: “It’s exciting that we can selectively choose the processes we want, and achieve the reaction we want which is inaccessible in nature. This could be a great platform for developing solar technologies. ̽��ֱ��approach could be used to couple other reactions together to see what can be done, learn from these reactions and then build synthetic, more robust pieces of solar energy technology.”

This model is the first to successfully use hydrogenase and photosystem II to create semi-artificial photosynthesis driven purely by solar power.

Dr Erwin Reisner, Head of the Reisner Laboratory, a Fellow of St John’s College, ̽��ֱ�� of Cambridge, and one of the paper’s authors described the research as a ‘milestone’.

He explained: “This work overcomes many difficult challenges associated with the integration of biological and organic components into inorganic materials for the assembly of semi-artificial devices and opens up a toolbox for developing future systems for solar energy conversion.”

Reference:
Katarzyna P. Sokół et al. 'Bias-free photoelectrochemical water splitting with photosystem II on a dye-sensitized photoanode wired to hydrogenase.' Nature Energy (2018). DOI: 10.1038/s41560-018-0232-y

Originally published on the St John's College website.

̽��ֱ��quest to find new ways to harness solar power has taken a step forward after researchers successfully split water into hydrogen and oxygen by altering the photosynthetic machinery in plants.

This could be a great platform for developing solar technologies.

Katarzyna Sokół

Experimental two-electrode setup showing the photoelectrochemical cell illuminated with simulated solar light

Yes

Low-impact hub generates electrical current from pure plant power

lw355 — Fri, 06 Mar 2015 09:00:52 +0000

A prototype “green bus shelter” that could eventually generate enough electricity to light itself, has been built by a collaboration of ̽��ֱ�� of Cambridge researchers and eco-companies.

̽��ֱ��ongoing living experiment, hosted by the Cambridge ̽��ֱ�� Botanic Garden and open to the visiting public, is incorporated in a distinct wooden hub, designed by architects MCMM to resemble a structure like a bus shelter. Eight vertical green wall units – created by green wall specialists, Scotscape – are housed along with four semi-transparent solar panels and two flexible solar panels provided by Polysolar.

̽��ֱ��hub has specially adapted vertical green walls that harvest electrons naturally produced as a by-product of photosynthesis and metabolic activity, and convert them into electrical current. It is the brainchild of Professor Christopher Howe and Dr Paolo Bombelli of the Department of Biochemistry. Their previous experiments resulted in a device able to power a radio using the current generated by moss.

̽��ֱ��thin-film solar panels turn light into electricity by using mainly the blue and green radiation of the solar spectrum. Plants grow behind the solar glass, ‘sharing the light’ by utilising the red spectrum radiation needed for photosynthesis, while avoiding the scorching effect of UV light. ̽��ֱ��plants generate electrical currents as a consequence of photosynthesis and metabolic activity during the day and night.

“Ideally you can have the solar panels generating during the day, and the biological system at night. To address the world’s energy needs, we need a portfolio of many different technologies, and it’s even better if these technologies can operate in synergy,” said Bombelli.

̽��ֱ��structure of the hub allows different combinations of the photovoltaic and biological systems to be tested. On the north east aspect of the hub, plants receive light directly, without being exposed to too much direct sun. On the south west orientation, a green wall panel is housed behind a semi-transparent solar panel so that the effect on the plants and their ability to generate current can be monitored. Next to that, in the same orientation, a single solar panel stands alone, and two further panels are also mounted on the roof.

“ ̽��ֱ��combination of horticulture with renewable energy production constitutes a powerful solution to food and resource shortages on an increasingly populated planet,” explained Joanna Slota-Newson from Polysolar. “We build our semi-transparent solar panels into greenhouses, producing electrical energy from the sun which can in turn be used to power irrigation pumps or artificial lighting, while offering a controlled environment to improve agricultural yields. In this collaboration with Cambridge ̽��ֱ��, the public can experience the plants’ healthy growth behind Polysolar panels.”

̽��ֱ��green wall panels in the hub are made from a synthetic material containing pockets, each holding a litre of soil and several plants. ̽��ֱ��pockets are fitted with a lining of carbon fibre on the back, which acts as an anode to receive electrons from the metabolism of plants and bacteria in the soil, and a carbon/catalyst plate on the front which acts as a cathode.

When a plant photosynthesises, energy from the sun is used to convert carbon dioxide into organic compounds that the plant needs to grow. Some of the compounds – such as carbohydrates, proteins and lipids – are leached into the soil where they are broken down by bacteria, which in turn release by-products, including electrons, as part of the process.

Electrons have a negative charge so, when they are generated, protons (with a positive charge) are also created. When the anode and cathode are connected to each other by a wire acting as an external circuit, the negative charges migrate between those two electrodes. Simultaneously, the positive charges migrate from the anodic region to the cathode through a wet system, in this case the soil. ̽��ֱ��cathode contains a catalyst that enables the electrons, protons and atmospheric oxygen to recombine to form water, thus completing the circuit and permitting an electrical current to be generated in the external circuit.

̽��ֱ��P2P hub therefore generates electrical current from the combination of biological and physical elements. Each element of the hub is monitored separately, and members of the public can track the findings in real time, at a dedicated website and on a computer embedded in the hub itself.

Margherita Cesca, Senior Architect and Director of MCMM Architettura, the hub’s designer, is pleased that it has garnered so much interest. “This prototype is intended to inspire the imagination, and encourage people to consider what could be achieved with these pioneering technologies. ̽��ֱ��challenging design incorporates and showcases green wall and solar panels as well as glass, creating an interesting element which sits beautifully within Cambridge ̽��ֱ�� Botanic Garden,” she said.

Bombelli added: “ ̽��ֱ��long-term aim of the P2P solar hub research is to develop a range of self-powered sustainable buildings for multi-purpose use all over the world, from bus stops to refugee shelters.”

̽��ֱ��P2P project was supported by a Partnership Development Award grant from the ̽��ֱ��’s EPSRC Impact Acceleration Account.

P2P is an outreach activity developed under the umbrella of the BPV (BioPhotoVoltaic) project working in collaboration with green technology companies including MCMM, Polysolar and Scotscape. ̽��ֱ��BPV project includes scientists from the Departments of Biochemistry, Plant Sciences, Physics and Chemistry at the ̽��ֱ�� of Cambridge, together with the ̽��ֱ�� of Edinburgh, Imperial College London and the ̽��ֱ�� of Cape Town.

Green wall technology and semi-transparent solar panels have been combined to generate electrical current from a renewable source of energy both day and night.

This prototype is intended to inspire the imagination, and encourage people to consider what could be achieved with these pioneering technologies

Margherita Cesca, MCMM Architettura

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Researchers show how plants tell the time

sj387 — Wed, 23 Oct 2013 19:00:00 +0000

Plants, like animals, have a 24 hour 'body-clock' known as the circadian rhythm. This biological timer gives plants an innate ability to measure time, even when there is no light - they don’t simply respond to sunrise, for example, they know it is coming and adjust their biology accordingly. This ability to keep time provides an important competitive advantage and is vital in biological processes such as flowering, fragrance emission and leaf movement.

BBSRC-funded scientists from the ̽��ֱ�� of Cambridge Department of Plant Sciences, are studying how plants are able to set and maintain this internal clock. They have found that the sugars produced by plants are key to timekeeping.

Plants produce sugar via photosynthesis; it is their way of converting the sun’s energy into a usable chemical form needed for growth and function.

This new research has shown that these sugars also play a role in circadian rhythms. Researchers studied the effects of these sugars by monitoring seedlings in CO2-free air, to inhibit photosynthesis, and by growing genetically altered plants and monitoring their biology. ̽��ֱ��production of sugars was found to regulate key genes responsible for the 24 hour rhythm.

Dr Alex Webb, lead researcher at the ̽��ֱ�� of Cambridge, explains: “Our research shows that sugar levels within a plant play a vital role in synchronizing circadian rhythms with its surrounding environment. Inhibiting photosynthesis, for example, slowed the plants internal clock by between 2 and 3 hours.”

̽��ֱ��research shows that photosynthesis has a profound effect on setting and maintaining robust circadian rhythms in Arabidopsis plants, demonstrating a critical role for metabolism in regulation of the circadian clock.

Dr Mike Haydon, who performed much of the research and is now at the ̽��ֱ�� of York added: “ ̽��ֱ��accumulation of sugar within the plant provides a kind of feedback for the circadian cycle in plants – a bit like resetting a stopwatch. We think this might be a way of telling the plant that energy in the form of sugars is available to perform important metabolic tasks. This mirrors research that has previously shown that feeding times can influence the phase of peripheral clocks in animals.”

Article credited to Biotechnology and Biological Sciences Research Council (BBSRC)

Plants use sugars to tell the time of day, according to research published in Nature today.

Our research shows that sugar levels within a plant play a vital role in synchronizing circadian rhythms with its surrounding environment

Alex Webb

Jucember

Arabidopsis Thaliana planted in Laboratory

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Scientists aim to improve photosynthesis to increase food and fuel production

gm349 — Mon, 11 Apr 2011 10:16:04 +0000

Two new initiatives at the ̽��ֱ�� of Cambridge aim to address the growing demand on the Earth’s resources for food and fuel by improving the process of photosynthesis.

As part of a new collaboration, the scientists have been awarded the major component of a $4M initiative to improve the process of photosynthesis, which allows biological systems to convert sunlight into food and is also the source of fossil fuels.

Four transatlantic research teams - two of which include academics from Cambridge’s Department of Plant Sciences - will explore ways to overcome limitations in photosynthesis which could then lead to ways of significantly increasing the yield of important crops for food production or sustainable bioenergy.

Professor Howard Griffiths from the Department of Plant Sciences said: “Plants really matter, and for the next generation, plant and microbial productivity will become the focus of key global issues: the basis for feeding an additional 2-3 billion mouths, to drive forward an economy currently trading on past sunlight, and maintain biodiversity in the face of climate change.”

̽��ֱ��funding has been awarded by the UK Biotechnology and Biological Sciences Research Council (BBSRC) and the US National Science Foundation (NSF) in a pioneering undertaking for the best minds from the USA and UK to join forces to explore this important research.

Despite the fact that photosynthesis is the basis of energy capture from the sun in plants, algae and other organisms, it has some fundamental limitations. There are trade-offs in nature which mean that photosynthesis is not as efficient as it could be - for many important crops such as wheat, barley, potatoes and sugar beet, the theoretical maximum is only 5%, depending on how it is measured. There is scope to improve it for processes useful to us, for example increasing the amount of food crop or energy biomass a plant can produce from the same amount of sunlight.

Some of the research will focus on improving a reaction driven by an enzyme called Rubisco, which is a widely recognised bottleneck in the photosynthesis pathway. By attempting to transfer parts from algae and bacteria into plants, the researchers hope to make the environment in the plants' cells around Rubisco richer in carbon dioxide which will allow photosynthesis to produce sugars more efficiently.

Professor Griffiths added: “ ̽��ֱ��enzymatic powerhouse Rubisco takes carbon dioxide from the atmosphere and uses light energy to produce sugars and other building blocks of life. However, the enzyme is rather flawed and somewhat promiscuous: it engages with oxygen as well as carbon dioxide, to the detriment of potential plant productivity.

“Some plants have evolved mechanisms, which act like biological turbochargers, to concentrate CO2 around Rubisco and improve the enzyme’s operating efficiency. These carbon concentrating mechanisms have evolved in certain key crops, such as sugar cane and maize. Other plants, such as aquatic algae, have developed mechanism in parallel which actively concentrate bicarbonate as a source of CO2 for Rubisco.”

̽��ֱ��research projects have been funded by BBSRC and NSF following a multidisciplinary workshop held by the funders in California in September 2010. ̽��ֱ��workshop, called the Ideas Lab, enabled scientists from different disciplines and institutions in the UK and USA to explore ideas and potential projects before submitting them to BBSRC and NSF.

̽��ֱ��Ideas Lab experience was likened by Professor Griffiths to be a combination of Big Brother, ̽��ֱ��Weakest Link and ̽��ֱ��Apprentice. Professor Griffiths is the consortium leader for one of the joint proposals funded, which will be exploring the operation of an algal carbon concentrating mechanism, and the possibility for introducing components into higher plant cells.

Dr Julian Hibberd from the Department of Plant Sciences is part of one of the other initiatives which is seeking to increase the efficiency of light harvesting by broadening the wavelengths of light, as used by bacteria, to power biophysical transport processes in higher plants.

This research will consolidate a major Plant Sciences initiative at Cambridge, which is exploring the means to improve photosynthesis from the perspective of sustainable plant productivity and crop yields for the future. Additional work is also being undertaken by Dr Hibberd to investigate the potential introduction of C4 photosynthetic traits into crops such as rice. This programme is part of a broader sweep of strategic research relevant to sustainable crop development, involving RNAi, pathogen suppression and epidemiological controls to maintain yields in a changing climate.

New collaboration aims to address the growing demand for food and fuel by improving the process of photosynthesis.

Plants really matter, and for the next generation, plant and microbial productivity will become the focus of key global issues: the basis for feeding an additional 2-3 billion mouths, to drive forward an economy currently trading on past sunlight, and maintain biodiversity in the face of climate change.

Professor Howard Griffiths

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Stooks

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