NCSU researchers develop 'self-processing' sweet potato for efficient ethanol production
Sweet potatoes are being re-engineered by North Carolina State University (NCSU) scientists as source of ethanol and bioplastics to help the U.S. bioproducts industry’s reliance on corn. The researchers' goal is to embed enzymes straight into the starch-rich tuber, so that it grows its own bioconversion enzymes and processes itself into biofuels. This would be yet another example of 'third generation' energy crops, which are being developed by several biotech firms and science teams (pevious post, here and here).
The industrial sweet potato can produce twice the starch content of corn – the leading source of ethanol in the U.S. Using plants from China, Africa, and South America, the NCSU scientists have created hybrids with starch contents over 50 percent higher than the sweet potatoes most Americans eat. These industrial sweet potatoes are capable of producing 'tremendous amounts of biomass', mostly starch-based. More starch means more sugars that can be fermented into ethanol.
Dr. Craig Yencho, an NC State associate professor of Horticultural Science, who is leading a project to develop alternative uses for the vegetable says the industrial sweet potato is edible, but not palatable. While the table version is orange inside and becomes sweet during baking as enzymes break down starch into sugar, the industrial sweet potato typically has a purple or white skin and white inside with a much higher starch content that limits its sweet taste.
North Carolina produces about 40 percent of the U.S. sweet potato crop. The industrial sweet potato could help diversify the state’s farm income. NCSU has several Potato and Sweetpotato Breeding and Genetics Programs running to research the use of the crop for the production of energy and bioproducts.
The biggest challenge is lowering production costs to take advantage of that higher starch content. Sweet potatoes traditionally are planted by hand using transplants, a process that costs up to 10 times as much as planting corn. But if a technique is developed to plant them the same way Irish potatoes are planted – by planting cut 'seed' pieces and mechanically planting them into the ground - planting costs could be cut in half.
In that case, ethanol production from sweet potatoes then becomes much more cost effective and feasible. Not only would these sweet potatoes be a much more viable ethanol source than corn, but because they are industrial sweet potatoes, farmers wouldn’t be taking away from a food source, says Yencho, who is currently in China helping the world’s number one producer of sweet potatoes tap the crop’s biofuel potential.
'Self-processing' crop
While the best of conventional breeding techniques have been used to develop NC State’s industrial sweet potato, Yencho is also teaming with colleague Bryon Sosinski, an associate professor of horticulture and the director of the Genome Research Lab, on an unconventional approach to further boost sugar – and thus ethanol – yield. Sosinski is trying to insert genes from bacteria that live in the hot waters around thermal vents on the ocean floor into sweet potato plants. The genes are active only at high temperatures, producing enzymes that break starch chains apart into much smaller sugars.
The goal is to produce what Yencho calls a 'self-processing' sweet potato that doesn’t need additives to be prepared for fermentation. The harvested roots could be thrown into a vat, and when the heat is turned up, the internal enzymes would digest the starch to a point where the resulting sugars could be fermented into fuel. Sosinski is now growing genetically modified sweet potato seedlings in the lab, and he hopes to move into greenhouse trials next year and into field plantings within three years:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: bioplastics :: starch :: sweet potato :: bioconversion :: biotechnology :: bioeconomy ::
The special genes used to grow the self-processing tuber would reduce the cost of enzymes that are used by biofuel processors to break down the starch in corn to sugars which are then converted into alcohol by fermentation.
Ultimately, NC State scientists believe the industrial sweet potato can compete with corn – now much cheaper to produce – as a viable alternative source of ethanol. Corn is by far the leading source of ethanol, but corn-based biofuel has come under increasing attack by poverty-fighting and other groups who argue, among other things, that diversion of corn crops for biofuels aggravates world-hunger problems. At the same time, Congress and state legislative leaders concerned about dependence on imported oil are pushing for increased use of biofuels. The new Energy Bill has given the corn ethanol industry a major boost.
And in their zeal to mine the tuber’s variability, Yencho and his team of NC State researchers have created a hybrid intended for neither food nor fuel – the non-bearing “Sweet Caroline” variety developed strictly for ornamental use.
References:
North Carolina State University News: NC State University Researchers Brewing Energy From Sweet Potatoes - November 30, 2007.
NCSU: Brewing Energy from Natural Resources [*.pdf].
North Carolina State University Potato and Sweetpotato Breeding and Genetics Website.
Biopact: Third generation biofuels: scientists patent corn variety with embedded cellulase enzymes - May 05, 2007
Biopact: Syngenta to trial third generation biofuel crop that grows its own bioconversion enzyme - November 12, 2007
Biopact: Agrivida and Codon Devices to partner on third-generation biofuels - August 03, 2007
Article continues
The industrial sweet potato can produce twice the starch content of corn – the leading source of ethanol in the U.S. Using plants from China, Africa, and South America, the NCSU scientists have created hybrids with starch contents over 50 percent higher than the sweet potatoes most Americans eat. These industrial sweet potatoes are capable of producing 'tremendous amounts of biomass', mostly starch-based. More starch means more sugars that can be fermented into ethanol.
Dr. Craig Yencho, an NC State associate professor of Horticultural Science, who is leading a project to develop alternative uses for the vegetable says the industrial sweet potato is edible, but not palatable. While the table version is orange inside and becomes sweet during baking as enzymes break down starch into sugar, the industrial sweet potato typically has a purple or white skin and white inside with a much higher starch content that limits its sweet taste.
North Carolina produces about 40 percent of the U.S. sweet potato crop. The industrial sweet potato could help diversify the state’s farm income. NCSU has several Potato and Sweetpotato Breeding and Genetics Programs running to research the use of the crop for the production of energy and bioproducts.
The biggest challenge is lowering production costs to take advantage of that higher starch content. Sweet potatoes traditionally are planted by hand using transplants, a process that costs up to 10 times as much as planting corn. But if a technique is developed to plant them the same way Irish potatoes are planted – by planting cut 'seed' pieces and mechanically planting them into the ground - planting costs could be cut in half.
In that case, ethanol production from sweet potatoes then becomes much more cost effective and feasible. Not only would these sweet potatoes be a much more viable ethanol source than corn, but because they are industrial sweet potatoes, farmers wouldn’t be taking away from a food source, says Yencho, who is currently in China helping the world’s number one producer of sweet potatoes tap the crop’s biofuel potential.
'Self-processing' crop
While the best of conventional breeding techniques have been used to develop NC State’s industrial sweet potato, Yencho is also teaming with colleague Bryon Sosinski, an associate professor of horticulture and the director of the Genome Research Lab, on an unconventional approach to further boost sugar – and thus ethanol – yield. Sosinski is trying to insert genes from bacteria that live in the hot waters around thermal vents on the ocean floor into sweet potato plants. The genes are active only at high temperatures, producing enzymes that break starch chains apart into much smaller sugars.
The goal is to produce what Yencho calls a 'self-processing' sweet potato that doesn’t need additives to be prepared for fermentation. The harvested roots could be thrown into a vat, and when the heat is turned up, the internal enzymes would digest the starch to a point where the resulting sugars could be fermented into fuel. Sosinski is now growing genetically modified sweet potato seedlings in the lab, and he hopes to move into greenhouse trials next year and into field plantings within three years:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: bioplastics :: starch :: sweet potato :: bioconversion :: biotechnology :: bioeconomy ::
The special genes used to grow the self-processing tuber would reduce the cost of enzymes that are used by biofuel processors to break down the starch in corn to sugars which are then converted into alcohol by fermentation.
Ultimately, NC State scientists believe the industrial sweet potato can compete with corn – now much cheaper to produce – as a viable alternative source of ethanol. Corn is by far the leading source of ethanol, but corn-based biofuel has come under increasing attack by poverty-fighting and other groups who argue, among other things, that diversion of corn crops for biofuels aggravates world-hunger problems. At the same time, Congress and state legislative leaders concerned about dependence on imported oil are pushing for increased use of biofuels. The new Energy Bill has given the corn ethanol industry a major boost.
There isn’t one magical crop that will solve our energy problems, but the industrial sweet potato can play an important role, especially in the southeastern U.S. where the crop is grown. - Dr. Craig Yencho, NC State associate professor of Horticultural ScienceResearch into the sweet potato for biofuels has added advantages: it can further enhance its value as a nutritional food staple while simultaneously finding new ways the crop can help replace petroleum as source for industrial products ranging from plastics to natural colorants and high-value specialty chemicals.
And in their zeal to mine the tuber’s variability, Yencho and his team of NC State researchers have created a hybrid intended for neither food nor fuel – the non-bearing “Sweet Caroline” variety developed strictly for ornamental use.
References:
North Carolina State University News: NC State University Researchers Brewing Energy From Sweet Potatoes - November 30, 2007.
NCSU: Brewing Energy from Natural Resources [*.pdf].
North Carolina State University Potato and Sweetpotato Breeding and Genetics Website.
Biopact: Third generation biofuels: scientists patent corn variety with embedded cellulase enzymes - May 05, 2007
Biopact: Syngenta to trial third generation biofuel crop that grows its own bioconversion enzyme - November 12, 2007
Biopact: Agrivida and Codon Devices to partner on third-generation biofuels - August 03, 2007
Article continues
Friday, December 21, 2007
EPSO vice-president: developing countries to play key role in climate-friendly bioenergy
Inzé's team at the Flanders Interuniversity Institute for Biotechnology (VIB) played an important role in mapping the poplar genome and in several other projects under the Joint Genome Institute which investigates energy crops. The VIB was founded by the father of modern plant bio-engineering, Marc Van Montagu (previous post). The breakthrough work of Inzé and the organisation of Ghent's plant sciences has contributed much to Belgium achieving the the title of being the 'world's best place' to work in scientific research (more here).
In the interview, Inzé says the developing world stands to gain from its enormous potential to produce biofuels and energy crops. The scientist also warns that if Europe doesn't ease its stance on genetically modified organisms (GMOs), its citizens will find it impossible to buy affordable food in the future.
Professor Inzé, you are focused on increasing the productivity and yield of crops. Can you describe the main challenges?
In the next decades we will have to feed three billion more people than today. Their living standard will be higher than that of the current generation, so they will want to consume more meat. Per kilogram of animal protein, you need seven kilograms of grain. The yield per hectare of crops will therefor have to increase significantly. Experiments with prototypes of genetically modified crops show we can increase production by 50 percent without extra inputs of nitrogen and other fertilizers.
Which crops are we talking about?
The main grain crops, like rice and maize. There is a tremendous amount of natural variation in plant growth. Some species remain tiny, while others grow in a spectacular manner, most notably a type of bamboo, the record holder - you can literally see it grow with the naked eye, at 1.2 meters per day. This opens interesting perspectives.
Isn't plant growth regulated by a whole range of genes?
Of course, and this is where systems biology proves to be so useful: we try to grasp the complexities of the entire process. It's possible to learn to understand the workings of all the components of an airplane, but really understanding how it stays in the air is something else. In the same way we try to gain insight into life in its full complexity, and to get there we start by learing what happens to the entire system when you push one of its buttons. It's excruciatingly complex, but we are making progress.
How many patents do you and your biotech team hold?
A very large number, and this is important because our investments must be protected. No company will ever invest tens of millions of euros in research and development if it can't enjoy the fruits of its own innovations. In 1998 we launched Crop Design. Last year we sold it to chemical giant BASF, which wants to commercialize our developments together with Monsanto. I expect our first genetically modified high yield crops to be on the market by 2013.
The public doesn't have a problem with genetic experiments in the field of human medicine. But in agriculture this is another matter, especially in Europe.
This is mainly a political problem. A select group of organisations has taken the issue of genetically modified organisms as a rallying point, uses it to scare people and to gain them for their cause. That's their only raison d'être. But you cannot apply the precautionary principle - which tells you to be careful for the effects of innovations and scientific interventions - endlessly. This stifles human progress. There are hundreds of scientific studies which prove our technologies are safe. Each day, hundreds of millions of people eat GMOs. You cannot continue to say that this is dangerous when you see, on a daily basis, that it's not.
Why don't you stress the environmental benefits of GMOs more often?
We try to do this, continuously. But organisations like Greenpeace and others refuse to understand that our technologies serve their cause. Isn't it useful to develop plants that can defend themselves against pests, so that we can radically cut back our use of pesticides? Our products aren't merely commercially interesting, they make sense from an ecological point of view.
Agriculture as it is being practised today can be quite polluting because of the heavy use of fertilizers. Moreover, fertilizers become ever more expensive because of high energy prices. With our technologies we can make agriculture both much cleaner and more efficient.
We are also developing dedicated energy crops for biofuels, which will allow us to make fuels in such a way that they do not impact food markets. This is important to all of us:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: biotechnology :: GMO :: energy crops :: developing countries :: Europe ::
Europe remains very skeptical and doesn't seem to be willing to ease its stance on GMOs.
I think things are changing. Europe doesn't have a choice because in the Americas and Asia the technology is gaining ground. Europe will start to lose and suffer if it can't compete in this field.
Some say that large companies are responsible for pushing a complex net of regulations in order to make it impossible for small biotech companies to compete.
This analysis isn't correct, I feel. Look at the pharmaceutical sector: small companies don't get any further than the first stages which consist of testing a new product. It then costs around 1 billion dollars to get such a new product to market. This is too much to ask of small biotech companies. In the agricultural sector it takes about 80 million euros to make something useful out of an innovation. These are gigantic sums of money. The point is that scale-advantages are crucial but can only be reaped by large companies. This trend is irreversible.
Do your patents get attacked?
Yes, all the time. It can take ages before you are granted a patent. My predecessors, professors Marc Van Montagu and Jef Schell, are the founding fathers of plant genetic engineering. Worldwide, some 110 million hectares of land grow crops based on their technologies. But it took them 20 years to get their final patents. Procedural attacks kept delaying the recognition. Only lawyers got better of this. But the simple fact remains: the patent system is the only approach that allows investors to get a return on their investments in this type of research.
But it is very important to understand the following: there is a consensus on the fact that genes as such should not be patentable, only innovations that allow you to work with these genes. The search for ways to side-step the full implications of a patented process often leads to new innovations. This way patents stimulate research, through scientific competitition.
In the patent for so-called 'golden rice' - the crop containing a gene that stimulates the production of the vitamin A precursor - it is stipulated that the technology must be made available for free to developing countries. Is this a good approach?
I think so. Billions of people eat white rice, which doesn't contain sufficient amounts of vitamin A. This can lead to blindness, especially amongst children. By inserting a gene from the wild daffodil into it, the rice produces beta-carotene. All studies demonstrate that this is a very safe product, but still it doesn't find its way to market. Syngenta, which developed the crop, is now offering it for free to countries whose people enjoy average living standards.
But is this profitable? Vitamin A deficiency manifests itself most amongst people in the poorest countries, doesn't it?
This is indeed the case and the return on investment would be low if the crop were to be sold in these countries. The same problem can be found in the field of tropical medicine - drugs are costly to develop but the purchasing power of those who need these medicines is too low to make an investment viable. This is why I think it would be useful to create separate international organisations both in the field of agriculture and in medical sciences to tackle this impasse.
But the third world does have an enormous potential in another sector: the field of bioenergy which must be tapped urgently as an alternative to fossil fuels. Plants convert the greenhouse gas CO2 into food and energy. Many developing countries have suitable agro-climatic conditions and could thus play a key role in producing climate friendly energy.
Shouldn't we be planting more trees here in Europe and Belgium?
Absolutely, that too. At our institute we have developed a fantastic technology to produce bioenergy from poplar trees [note: Inzé and his collegues helped map the genome of the poplar tree - the first tree to have had its entire genetic profile published; the effort was part of the international Joint Genome Institute's research into genomics of bioenergy crops - previous post; on the basis of their research they designed a poplar with low lignin and high biomass yields]. Crops like rapeseed, which receive a lot of attention today, are less interesting for biofuels, because they require too many inputs. A tree grows all by itself. With minimal inputs you get a maximal output. We have now filed for a permission to trial our genetically modified energy poplar in the field.
Aren't you afraid that people will resist this? It's been five years since the last GMO field trials in our country.
Luckily, we play a role on a world scale. Europe's agriculture can only survive because of massive subsidies. If the Union doesn't relax its rules for new technologies, European citizens will no longer be able to buy food. The Food & Drug Administration (FDA) in the United States, which regulates new technologies and approves new products, is an excellent institution, an oracle of scientific common sense. We urgently need a similar body here in Europe.
Today we are too dependent on the vagaries of idiosyncratic opinions in Europe - of what the German Greens think at a particular moment in time or of a sentiment uttered by the new french President.
Translated from Dutch for Biopact.
Image: sun setting over a sugarcane field in Malawi. A new dawn for Africa?
References:
Dirk Draulans, "Niemand mag genen bezitten" [Nobody should own genes], Knack, pp. 89-94, December 19, 2007.
Biopact: Celebrity spotting: Marc Van Montagu and GM energy crops - July 05, 2007
Biopact: The first tree genome is published: Poplar holds promise as renewable bioenergy resource - September 14, 2006
Biopact: Moss genome sequenced: shows how aquatic plants adapted to dry land - key to development of drought-tolerant energy crops, cellulosic biofuels - December 14, 2007
Article continues
posted by Biopact team at 6:28 PM 0 comments links to this post