Scientist explores deep ocean storage of carbon - another option for carbon negative bioenergy

Imagine a gigantic, inflatable, sausage-like bag capable of storing 160 million tonnes of CO2 - the equivalent of 2.2 days of current global emissions. Now try to picture that container, measuring up to 100 metres in radius and several kilometres long, resting benignly on the seabed more than 3 kilometres below the ocean's surface and staying there forever. That would offer a way of storing carbon dioxide permanently and thus help in the fight against climate change.

At first blush, this might appear like science fiction, but it's an idea that gets serious attention from Dr. David Keith, one of Canada's foremost experts on carbon capture and sequestration. Keith will talk on the subject at the 2008 Annual Conference of the American Association for the Advancement of Science in Boston at a session entitled "Ocean Iron Fertilization and Carbon Sequestration: Can the Oceans Save the Planet?"

Shooting rockets full of sulphur into the high atmosphere to emulate the cooling effect of volcanic eruptions, launching space mirrors, making artificial reflective clouds, or building costly synthetic trees - there are a lot of gee-whiz (and risky) "geo-engineering" ideas for dealing with global warming that are really silly, remarks Keith, an NSERC grantee and director of the Energy and Environmental Systems Group at University of Calgary-based Institute for Sustainable Energy, Environment and Economy. At first glance his own idea looks nutty, but as one looks closer it seems that it might technically feasible with current-day technology. But, adds Keith, who holds the Canada Research Chair in Energy and the Environment, it's early days and there is not yet any serious design study for the concept.

Carbon storage is receiving more and more attention as climate change needs radical interventions. Capturing and storing CO2 from (biomass) power plants and other point sources comes in a variety of forms:

1. the gas can be captured and stored in geological formations such as depleted oil and gas fields, saline aquifers, unmineable coal seams or special rock formations; this storage technique is called "geosequestration"
2. alternatively, carbon can be captured and stored either in gaseous or in a solid form at the bottom of the ocean, where it would remain contained for millennia - "ocean storage"
3. carbon dioxide can also be captured and transformed into stable, inert products, via mineralisation processes
   
4. last but not least, carbon can be stored in an inert form in soils; this technique is based on biochar, obtained from biomass; soil sequestration has many advantages: it is both relatively simple and cost-effective, and improves soil qualities considerably; biochar systems yield negative emissions, because the biomass delivers both energy as well as a carbon sink
   

All these carbon sequestration techniques can be applied to CO2 from biomass power plants and decarbonised biofuel production. In this case, a "negative emissions" energy system can be designed that removes CO2 emissions from the past. Actively taking CO2 out of the atmosphere with such carbon-negative bioenergy systems, is the most radical tool in the climate fight. No other energy system can become carbon negative. Such bio-energy with carbon storage (BECS) systems are seen as one of the few cost-effective, feasible and safe geo-engineering option.

But these systems require efficient carbon capture, transportation and storage strategies. Biopact has been focusing both on carbon capture and storage (CCS) based on geosequestration and biochar, but ocean storage could be an alternative.

The original idea of ocean storage was conceived several years ago by Dr. Michael Pilson, a chemical oceanographer at the University of Rhode Island, but it really took off last year when Keith confirmed its feasibility with Dr. Andrew Palmer, a world-renowned ocean engineer at Cambridge University. Keith, Palmer and another scientist at Argonne National Laboratory later advanced the concept through a technical paper prepared for the 26th International Conference on Offshore Mechanics and Arctic Engineering in June 2007.

The Abyss
Keith sees this solution as a potentially useful complement to CO2 storage in geological formations, particularly for CO2 emanating from sources near deep oceans. He believes it may offer a viable solution because vast flat plains cover huge areas of the deep oceans. These abyssal plains have little life and are benign environments. Abyssal plains are flat or very gently sloping areas of the deep ocean basin floor, covering approximately 40% of the ocean floor and reaching depths between 2,200 and 5,500 m (7,200 and 18,000 ft). They generally lay between the foot of a continental rise and a mid-oceanic ridge (image, click to enlarge):
energy :: sustainability :: biofuels :: biomass :: bioenergy :: geo-engineering :: carbon capture and storage :: geosequestration :: ocean storage :: bio-energy with carbon storage :: negative emissions :: carbon negative :: climate change ::

If we stay away from the steep slopes from the continental shelves, the abyssal plains are a very quiet environment, says Keith.

For CO2 to be stored there, the gas must be captured from power and industrial point sources, compressed to liquid, and transported via pipelines that extend well beyond the ocean's continental shelves. When the liquid CO2 is pumped into the deep ocean, the intense pressure and cold temperatures make it negatively buoyant.

This negative buoyancy is the key, explains Keith. It means the CO2 wants to leak downwards rather than moving up to the biosphere.

The use of containment is necessary because CO2 will tend to dissolve in the ocean, which could adversely impact marine ecosystems. Fortunately, says Keith, the cost of containment is quite minimal with this solution. He and his colleagues calculate that the bags can be constructed of existing polymers for less than four cents per tonne of carbon.

The real costs lie in the capture of CO2 and its transport to the deep ocean. If we can drive those down, he notes, then ocean storage might be an important option for reducing CO2 emissions.

Image: the Abyssal Plains. Credit: Encyclopedia Britannica.

References:
David Keith, "Engineered Storage on the Abyssal Plain: prospects to a new approach to ocean carbon storage and some thoughts about geoengineering", Department of Chemical and Petroleum Engineering, University of Calgary, AAAS Annual Meeting 2008, Ocean Iron Fertilization and Carbon Sequestration: Can the Oceans Save the Planet.

Natural Sciences and Engineering Research Council of Canada: Into the Abyss: Deep-sixing Carbon - February 18, 2008.

Biopact: The end of a utopian idea: iron-seeding the oceans to capture carbon won't work - April 26, 2007

Biopact: WWF condemns Planktos Inc. iron-seeding plan in the Galapagos - June 27, 2007

Biopact: Simulation shows geoengineering is very risky - June 05, 2007

Biopact: Climate change and geoengineering: emulating volcanic eruption too risky - August 15, 2007

Biopact: Capturing carbon with "synthetic trees" or with the real thing? - February 20, 2007

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Novel organic metal hybrids revolutionize materials science and chemical engineering - applications in biogas and biohydrogen storage

A novel class of hybrid materials made from metals and organic compounds is changing the face of solid state chemistry and materials science just 10 years after its discovery, with applications already in safe storage of highly inflammable gases such as hydrogen and methane promising to make the introduction of biohydrogen and biomethane as transport fuels more feasible. Other applications of interest to the bioenergy community include efficient CO2 capture (for carbon-negative bioenergy systems), novel liquids separation processes in biofuel production (nanostructured molecular sieves) and the development of new catalysts.

Europe is aiming to capitalise on core strengths in the field and build critical mass by combining the diverse range of skills required within a coherent research network, following a major workshop organised by the European Science Foundation (ESF).

The materials called Metal Organic Frameworks (MOFs) represent one of the biggest breakthroughs in solid state science whose potential is only just being realised, according to Gérard Ferey of the Institut Lavoisier at the University of Versailles, who convened the ESF workshop titled Genesis and Applications of Active Metal Organic Frameworks [*.pdf].

The domain is currently exploding, and there are so many potential applications that it is difficult to decide how to prioritise them. The only limit is our imagination. There is no doubt though that the first big application of MOFs - storage of gases - will be highly important, given the urgency of developing alternatives to fossil fuels for automobiles. For hydrogen storage, MOFs are already used, and many carmakers have these products in prototypes. - Gérard Ferey, Institut Lavoisier

MOFs are porous materials with microscopic sized holes, resembling honeycombs at molecular dimensions. This property of having astronomical numbers of tiny holes within a relatively small volume can be exploited in various ways, one of which is as a repository for gases. Gas molecules diffuse into the MOF solid and are contained within its pores.

In the case of gas storage, MOFs offer the crucial advantage of soaking up some of the gas pressure exerted by the molecules. This makes hydrogen derived from non-fossil energy sources such as biomass, or even genetically engineered plants, potentially viable as a fuel for cars while the alternative of pressurised canisters is not, says Ferey. The key difference is that the amount of gas stored in a conventional cylinder at say 200 atmospheres pressure could be accommodated in an MOF vessel of the same size at just 30 atmospheres, which is much safer:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: metal organic frameworks :: solid state chemistry :: materials science :: biofuels :: gas storage :: carbon capture :: biogas :: biohydrogen ::

The porous nature of MOFs enables them to be exploited in quite another way as catalysts to accelerate chemical reactions for a wide variety of materials production and pharmaceutical applications, although this field, as Ferey noted, is still in its infancy. Yet already the field is gaining interest beyond academia from serious companies, with a significant development at the ESF workshop being the presence and support of German chemicals giant BASF. This in turn has provided high endorsement of the field's potential and has stimulated interest from other companies, according to Ferey.

But several challenges remain before this potential can be realised, the first one being to assemble research and development teams with the right body of skills. As Ferey noted, many of the skills already exist but the researchers need to expand their horizons and focus more broadly on the big picture beyond their specialised domains.

There is also the technical challenge of learning first how these materials are formed, and then applying the knowledge to design MOFs matched to specific requirements. MOFs are crystalline solids that form in highly regular patterns from solutions, just as salts and sugars do. Researchers need to learn how to manipulate the starting conditions to obtain just the crystalline composition and arrangement they want.

The ESF Exploratory Workshop, Genesis and Applications of Active Metal Organic Frameworks, held in Dourdan near Paris in France in April 2007, was one of the first dedicated to this highly promising field whose potential has been underestimated until now. The next objective for Ferey is to establish a research network within the European Union's Seventh Framework Programme (FP7). Each year, ESF supports approximately 50 Exploratory Workshops across all scientific domains. These small, interactive group sessions are aimed at opening up new directions in research to explore new fields with a potential impact on developments in science.

Image: example of a nanoporous MOF's molecular structure. Credit: ESF.

References:
European Science Foundation, Standing Committee for Physical and
Engineering Sciences (PESC), Exploratory Workshop: Genesis and Applications of Active Metal-Organic Frameworks [*.pdf], Dourdan, France, 25 - 28 April 2007 Convened by: Gérard Ferey, Institut Lavoisier (UVSQ), Département de Chimie, Université de Versailles St. Quentin en Yvelines.

European Science Foundation: Novel organic metal hybrids that will revolutionize materials science and chemical engineering - February 18, 2008

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M&G invests €100 million in Europe's largest cellulosic ethanol plant; €120 million for research

Italian chemical group Mossi & Ghisolfi (M&G) plans to build a 200,000-tonne ethanol plant and convert it to using cellulose feedstock to make next-generation biofuels. M&G Vice President Guido Ghisolfi said the group with partners would invest €100 million (US$148.1 million) to build the plant in Italy by 2009 and €120 (US$175.9) more in research to convert it to cellulose feedstock later on.

The plant in the north Italian region of Piedmont would produce 200,000 tons, or about 2.5 million hectoliters of bioethanol to help Italy meet its bioethanol target of about 1 million tons by 2010.

"Our goal is to be competitive with Brazilian ethanol even without subsidies," Ghisolfi said on the sidelines of a biofuels conference organised with the Global Bioenergy Partnership.

The new plant would initially use 600,000 tons of maize as feedstock and Tortona-based M&G has already lined up local farmers to deliver grain as it aims to cover 60 percent of feedstock needs with local supplies. M&G, which is the world's biggest producer of PET for packaging, last year started a research aimed at converting the future bioethanol plant from maize to fiber sorghum - a high yielding biomass crop.

Italian researchers have been developing hybrid sorghums with a focus on biomass production. The tropical plants have been made to thrive in European conditions. Some of the hybrids grow to a height of 4 to 4.5 meters (13-15ft) and contrary to miscanthus, switchgrass or other energy crops, they require no irrigation and less fertilizer. Trials show impressive yields of 30 and 40 tons of dry matter biomass per hectare (12 - 16 tons/acre) (graph, click to enlarge).

M&G will be drawing on such energy crops and has already presented an evaluation of environmental impact of the new plant - a key document for getting a government permit for any big industrial project in Italy - to the government and planned to start works in May 2008:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: cellulosic ethanol :: energy crops :: sorghum :: climate change :: Italy ::

The new plant's output would be sold mostly in Italy where a number of major petrol distributors have pledged to boost bioethanol blend sold at their pump stations from 2008. The group aims to launch a demonstration plant by 2012 which will have a 20,000 ton annual output.

An increasing number of scientists and producers say that the second-generation biofuels, which are made from non-edible crops and even municipal waste, will be highly effective against climate change.

Ghisolfi said M&G would aim to sell its second-generation technology once it is developed.

Research is under way around the world to develop the second-generation biofuel technology, but experts say it could take a few more years before they become commercially sustainable and profitable.

Corrado Clini, chairman of Global Bioenergy Partnership, said M&G's project is set to be the biggest in Europe and would help Italy - which has been lagging behind other European Union countries in hitting EU's biofuels targets - become the leader in the second-generation biofuels research.

Picture: biomass sorghum yields high amounts of cellulose for conversion into bioproducts; it requires less water and fertilizer than other high yielding tropical energy crops.

References:
Mossi & Ghisolfi: Bio-Ethanol Conference: "Second Generation Ethanol - A realistic challenge", Tortona (Italy) - February 5, 2008.

Reuters: Italy's M&G to build bioethanol plant - February 18, 2008.

Andreina Belocchi, Fabrizio Quaranta, Valerio Mazzon, Nicola Berardo, Ersilio Desiderio, "Fibre sorghum: influence of the harvesting methods on plant moisture and fibre content" [.*pdf], Interactive European Network for Industrial Crops and their Applications.

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Scientists: conservationists' studies about biofuel emissions "misleading" and "bad science"

Scientists from several universities, from the U.S. Department of Energy's Argonne National Laboratory and scientists from the DOE Biomass Program are questioning the conclusions and assumptions of two reports that were published recently in the journal Science. The reports about the carbon footprint of biofuels resulting from land use changes - written by conservationists - were "narrowly constructed" to demonstrate "worst-case scenarios" only and did not examine all the facts of biofuel production. The basic facts are now put into question by scientists who see the studies as "misleading" and "bad science". This fact brings into question the role conservationists can play in the bioenergy debate.

The studies made claims that land-use change from biofuels results in large greenhouse gas emissions (previous post). While this is true for highly exceptional forms of land-use change, such as the conversion of peat swamps that store high amounts of carbon, scientists doubt whether this is true for the vast bulk of other types of land used to grow energy or food crops. Peat swamps occur in selected sites on Borneo Island, for example. But Borneo's peat swamps are hardly representative for the rest of the world's land base. Likewise, the data about land use emissions in other types of land are seriously put into question. Lastly, new land use techniques eliminate the problem alltogether (more here).

The bioenergy community accepts that the entire lifecycle of biofuel and biomass production must be taken into account. But conservationists' attempts to narrow down the debate and make it look as if all biofuels are based on deforestation or the destruction of special types of high carbon land, is not helpful. It damages their case, as their views on biofuels lose credibility each time they publish such misleading material.

Conservationists have launched a hard campaign against bioenergy, and they will not hesitate to distort realities, by extrapolating exceptional excesses and representing them as the rule. Just recently, a group made headlines by claiming that "biofuels fuel human rights abuses" - another report based on practises in Indonesia that are much less clear cut, but that are being presented as the rule. Cultural anthropologists cautioned against this practise of simplifying debates, because they are not only bad science, they also result in paternalistic and even racist representations of 'indigenous communities' (previous post).

In short, conservationists are quickly losing their legitimacy to play a role in the bioenergy debate - both when it comes to their view on the environmental and the social impacts of biofuels. They are potentially destroying an opportunity to help fight climate change. Worse, they are also potentially eliminating the possibility for poor people in developing countries to make a living from participating in bioenergy production. Even more, smart biofuels can actually help conserve ecosystems, but surprisingly conservationists are not willing to recognise this important aspect of an emerging sector.

Dr. Michael Wang of Argonne’s Transportation Technology R&D Center and Zia Haq of the DOE’s Office of Biomass Program spoke out against the study about the indirect land use change effects of ethanol production in the U.S. They say that there has been no indication that production has so far caused land use changes in other countries because U.S. corn exports have been maintained at about 2 billion bushels a year.

While scientific assessment of land use change is needed, Wang and Haq say conclusions about green house gas emissions and biofuels based on "speculative, limited land use change modeling is misguiding".

Dr. Lou Honary, Director of the National Ag-Based Lubricants Center at the University of Northern Iowa says the reports are "overly simplistic", "don't take in many related factors", and "cause misconceptions":
energy :: sustainability ::biomass :: bioenergy :: biofuels :: ethanol :: biodiesel :: lifecycle :: emissions :: land use change :: conservationism :: bad science ::

Michigan State University's Dr. Bruce Dale agrees with Honary and says there are strong reasons to question the assumptions, data and comparisons made in these two papers.

David Morris of the Institute of Self-Reliance, a former member of the Advisory Committee for Biomass to the Departments of Energy and Agriculture, finds many contradictions in the reports.

"The report notes that the vast majority of today’s ethanol production comes from corn cultivated on land that has been in corn production for generations," Morris says. "Since little new land has come into production, either directly or indirectly, the current use of ethanol clearly reduces greenhouse gas emissions."

References:
Farm Futures: Doubts Raised About Recent Global Warming Studies - February 18, 2008.

Argonne National Laboratory: Transportation Technology R & D Center.

U.S. DOE, Energy Efficiency & Renewable Energy: Biomass Program.

Biopact: New land use techniques boost benefits of biofuels - February 08, 2008

Biopact: Two studies state the obvious: clearing high carbon land for first-generation biofuels can lead to higher emissions - February 08, 2008

Biopact: Anthropologists caution against essentialism in discussion about social sustainability of biofuels - February 13, 2008

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Researchers find geosequestration of CO2 much safer than thought

A new study has revealed that storing carbon dioxide beneath the earth may be a safer and longer term method of reducing emissions in the atmosphere than previously thought. A team of NERC funded researchers at the University of Manchester, the University of Houston and the University of Toronto, found that carbon dioxide (CO2) has been naturally stored for up to 40 million years in CO2 gas fields in the Colorado Plateau and Rocky Mountains of the USA. Their findings are published in the geochemistry journal Geochimica et Cosmochimica Acta.

This is important news for those in the bioenergy community looking at the potential of coupling geosequestration to bioenergy production. When carbon capture and storage (CCS) technologies are applied to biomass power plants, a system that yields 'negative emissions' emerges - the most radical tool in the climate fight.

Ordinary renewables are all 'carbon neutral' at best, slightly carbon positive in practise. That is, they add small amounts of CO2 to the atmosphere over their lifecyle. But bio-energy with carbon storage (BECS) actively removes CO2 from the atmosphere and locks it up under ground. The difference is radical: whereas renewables like solar, non-CCS biomass, wind or hydropower yield between +15 to + 100 g of CO2 per kWh of electricity produced, carbon-negative bioenergy yields up to -1000g (that is, "minus", hence 'negative emissions' - see figure, click to enlarge).

Scientists have found that such BECS systems, if implemented on a global scale, can clean up the atmosphere and take us back to pre-industrial atmospheric CO2 levels by 2060. It is a feasible 'geo-engineering' concept that allows societies to function as normal, while not only eliminating their carbon emissions, but actually removing CO2 from the past. As more and more scientists call for radical steps to fight climate change, carbon-negative bioenergy might become one of the only instruments available to do so.

BECS systems put the carbon we pumped into the atmosphere since the Industrial Revolution back where it belongs: under ground. And the great thing is that, while doing so, renewable energy is generated (solar energy stored in biomass).

One of the hurdles standing in the way of adopting CCS has been doubts over the safety and permanence of geosequestration. The potential for leakage is often leveled against those who advocate CCS coupled to power plants that burn fossil fuels. A leak would mean a net contribution of carbon emissions. However, when coupled to biomass power plants, leakage is of lesser concern, because the CO2 is biogenic in origin. Leaks would not result in net CO2 emissions, because the fuel from which the gas was derived is carbon neutral from the start.

The new research however shows the safety argument against geosequestration might be exaggerated, as natural sites are shown to do the trick of storing CO2 gas safely for millions of years. The scientists took CO2 samples from five natural gas fields and measured their noble gases. Their findings allowed them to ‘fingerprint’ the Colorado CO2 for the first time:
energy :: sustainability :: biofuels :: biomass :: bioenergy :: carbon capture and storage :: geosequestration :: precautionary principle :: carbon negative :: negative emissions :: bio-energy with carbon storage :: climate change ::

The results show that the gas in the fields has been released from molten magma within the Earth’s crust. In all of these fields, the last time the magma melted and CO2 was released was more than eight thousand years ago. In three of the fields, it last occurred over a million years ago, and in one it was at least 40 million years ago. This proves that the CO2 has been stored naturally and safely in the earth for periods between eight thousand years and 40 million years - Dr. Stuart Gilfillan, lead researcher

The scientists hope this study will pave the way for selection of similar safe sites for storage of CO2 from power plants in both the UK and abroad. Underground CO2 storage, in the correct place, should be a safe option to help us cope with emissions until we can develop cleaner energy sources. A suitable storage place for the UK could be in the North Sea, where similar rocks to those in the gas fields can be found, they say.

References:
Stuart M.V. Gilfillana, Chris J. Ballentine, Greg Holland, Dave Blagburn, Barbara Sherwood Lollar, Scott Stevens, Martin Schoell and Martin Cassidy, "The noble gas geochemistry of natural CO2 gas reservoirs from the Colorado Plateau and Rocky Mountain provinces, USA", Geochimica et Cosmochimica Acta, 15th February 2008, Vol 72, No. 4, p1174-1198.

Biopact: New study shows stabilizing climate requires near-zero carbon emissions now - boosts case for carbon-negative bioenergy - February 15, 2008

Scientific literature on negative emissions from biomass:
H. Audus and P. Freund, "Climate Change Mitigation by Biomass Gasificiation Combined with CO2 Capture and Storage", IEA Greenhouse Gas R&D Programme.

James S. Rhodesa and David W. Keithb, "Engineering economic analysis of biomass IGCC with carbon capture and storage", Biomass and Bioenergy, Volume 29, Issue 6, December 2005, Pages 440-450.

Noim Uddin and Leonardo Barreto, "Biomass-fired cogeneration systems with CO2 capture and storage", Renewable Energy, Volume 32, Issue 6, May 2007, Pages 1006-1019, doi:10.1016/j.renene.2006.04.009

Christian Azar, Kristian Lindgren, Eric Larson and Kenneth Möllersten, "Carbon Capture and Storage From Fossil Fuels and Biomass – Costs and Potential Role in Stabilizing the Atmosphere", Climatic Change, Volume 74, Numbers 1-3 / January, 2006, DOI 10.1007/s10584-005-3484-7

Further reading on negative emissions bioenergy and biofuels, and carbon capture techniques:
Peter Read and Jonathan Lermit, "Bio-Energy with Carbon Storage (BECS): a Sequential Decision Approach to the threat of Abrupt Climate Change", Energy, Volume 30, Issue 14, November 2005, Pages 2654-2671.

Stefan Grönkvist, Kenneth Möllersten, Kim Pingoud, "Equal Opportunity for Biomass in Greenhouse Gas Accounting of CO2 Capture and Storage: A Step Towards More Cost-Effective Climate Change Mitigation Regimes", Mitigation and Adaptation Strategies for Global Change, Volume 11, Numbers 5-6 / September, 2006, DOI 10.1007/s11027-006-9034-9

Biopact: Commission supports carbon capture & storage - negative emissions from bioenergy on the horizon - January 23, 2008

Biopact: The strange world of carbon-negative bioenergy: the more you drive your car, the more you tackle climate change - October 29, 2007

Biopact: "A closer look at the revolutionary coal+biomass-to-liquids with carbon storage project" - September 13, 2007

Biopact: New plastic-based, nano-engineered CO2 capturing membrane developed - September 19, 2007

Biopact: Plastic membrane to bring down cost of carbon capture - August 15, 2007

Biopact: Pre-combustion CO2 capture from biogas - the way forward? - March 31, 2007

Biopact: Towards carbon-negative biofuels: US DOE awards $66.7 million for large-scale CO2 capture and storage from ethanol plant - December 19, 2007

Biopact: Biochar and carbon-negative bioenergy: boosts crop yields, fights climate change and reduces deforestation - January 28, 2008

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Scientists discover maize oil gene; could help development of high yielding oil crops

A team of crop geneticists in the United States have identified a key gene that determines oil yield in maize kernels, a finding that could have repercussions for the fast-expanding biofuels industry with applications in developing high yielding oil crops. Results are published as an advance online article in Nature Genetics.

Lead author Bo Shen, plant scientist of DuPont unit Pioneer Hi-Bred International, writes oil is an important renewable resource for biodiesel production and for dietary consumption by humans and livestock.

Through genetic mapping of the oil trait in plants, studies have reported multiple quantitative trait loci (QTLs) with small effects, but the molecular basis of oil QTLs remains largely unknown. The researchers discovered a high-oil QTL which affects maize seed oil and oleic-acid contents by encoding an acyl-CoA:diacylglycerol acyltransferase (DGAT), which catalyzes the final step of oil synthesis.

The gene that encodes for the catalysing enzyme lies on Chromosome 6 of the maize genome.

In addition, a tiny amino acid variant within this gene can boost the yield of oil and oleic acid - the sought-after edible fat in corn - by up to 41 percent and 107 percent respectively.

The paper, written by a 16 strong team from the US chemicals and agribusiness giant DuPont, was based on a comparison of 71 strains of maize whose oil content ranged from low to high:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: biodiesel :: oilseed :: maize :: genetics :: biotechnology ::

Their work provides insights into the molecular basis of natural variation of oil and oleic-acid contents in plants and highlights DGAT as a promising target for increasing oil and oleic-acid contents in other crops.

Present-generation biodiesel is derived from oilseed crops such as soybean, palm oil, jatropha and rapeseed. Some of these have low yields but a low environmental footprint while others with higher yields can have detrimental effects on the environment if their cultivation leads to, e.g. deforestation or peat swamp destruction.

By boosting oil yields, less land would be required, the energy balance of the fuel would increase, it would help reduce greenhouse gas emissions further and pressures on the environment would be lowered.

References:
Peizhong Zheng, William B Allen, Keith Roesler, Mark E Williams, Shirong Zhang, Jiming Li, Kimberly Glassman, Jerry Ranch, Douglas Nubel, William Solawetz, Dinakar Bhattramakki, Victor Llaca, Stéphane Deschamps, Gan-Yuan Zhong, Mitchell C Tarczynski & Bo Shen, "A phenylalanine in DGAT is a key determinant of oil content and composition in maize", Nature Genetics, Published online: 17 February 2008 | doi:10.1038/ng.85

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