Across the country, researchers are looking into whether genetically modified crops and other high-tech tools can transform plants into low-carbon fuels.
Biofuels are often considered a replacement for the fossil fuels used to power vehicles and aircrafts. Companies around the world, from airlines to oil refiners, mix plant-based fuels with gasoline and jet fuel to lower the levels of carbon emissions.
But major questions remain about whether biofuels are environmentally friendly. Experts point out that cultivating biofuels can lead to soil erosion or deforestation, and many of the crops used to make fuel require substantial amounts of land, water, and energy. What’s more, biofuel production is expensive, making it difficult for consumers to use higher volumes of biofuel than traditional fossil fuels.
Now, researchers across the US are pouring resources into discovering whether it’s possible to produce sustainable biofuel through selective plant breeding and genetic modification. That technique, which has generated controversy in the food industry, is seen as a useful tool in the race for cleaner, better fuels. What’s more, new technologies, such as big data analytics and advanced robotics, are aiding in the quest to discover which plants work best for fuel production.
“We’re using sensors to measure the plants in the field,” explains Chris Boomsma, managing director of a new project based out of Purdue University in Indiana that aims to identify the best genetic traits in plants for biofuel production. “Then we use crop models to work out what traits we should pursue to bring down costs and increase outputs, and we look at how much water the crop uses, how much fertilizer, and how much nitrogen.”
Making biofuel is expensive and challenging. It requires that plant cellulose be removed from the biomass, an expensive process that requires extracting cellulose from the part of the plant called the lignin. Plants must be soaked in hot acid or placed under steam pressure, which requires an expensive grade of stainless steel.
That’s where genetic modification and selective plant breeding could be helpful. Scientists are now working to genetically modify plants to remove the genes that cause lignin production, making it easier and cheaper to remove plant cellulose without acid treatment. Still, plants without lignin often produce lower yields and are more susceptible to pathogens or rust. That means more plants must be used to produce the same amount of fuel.
At Purdue University, however, researchers are addressing these issues by eschewing genetic modification and opting for traditional plant breeding with a high-tech twist. In their work to discover the ideal traits for biofuel, researchers use drones and ground robotics fitted with sensors to record the characteristics of sorghum plants. The project is part of a larger research program funded by the Department of Energy’s Advanced Research Projects Agency.
The machines register everything from plant height and biomass to leaf number and leaf angle, Dr. Boomsma explains. The researchers then create three-dimensional models of the plants to visualize the data and make connections between the plant traits and genes.
“Once you know which genes go with which physical characteristic of the plant, you can then breed better sorghum plants,” says Boomsma. “One of the traits would be more biomass production, so the more plant you have the more fuel you can make out of it.”
The researchers are also looking for plant varieties with mutations that lend themselves to digestibility, or that have the right sugar content for making biofuel.
Meanwhile, EdenSpace, a crop biotechnology company based in Virginia, is trying a different method. It uses genetic modification to produce enzymes within the plant tissues that make it easier to break the plants down. Its aim is to reduce the amount of crops needed to produce biofuel by creating inexpensive sugars that can be fermented into ethanol.
“One of the things we noticed was that we needed a more efficient way to break down the cellulose,” says Michael Blaylock, CEO of EdenSpace. “We can engineer the plant to make it more suitable and require less energy and fewer chemicals, but we have to do that so we’re still able to grow a crop that’s sustainable and that is resistant to disease and suitable for agricultural use.”
EdenSpace originally began researching biofuel production from corn because there was already a large market available for corn ethanol, Mr. Blaylock says. Eventually, however, they switched to other plants like poplar. The genetic modification of food crops is often heavily regulated, so the company found it was easier to experiment with plants that aren’t used for food consumption. Meanwhile, they also discovered other environmental benefits from using poplar.
“I think the thing that’s attractive about the woody biomass crops is that it uses very little soil,” says Blaylock. “You just harvest the top, you aren’t disrupting the soil and you have this root mass that is developing and adding nutrients.”
The push for better biofuels kicked into high gear in 2007, when Congress passed the Renewable Fuel Standard. The RFS requires that a minimum amount of biofuels be blended into the US fuel mix, but gasoline refiners and other groups have pushed back, saying most vehicles can’t handle a high percentage of biofuel in their engines. In most pumps around the country, gasoline contains 10 percent biofuel. Still, environmental advocates say that amount could be raised to 15 percent to reduce greenhouse gas emissions without jeopardizing engines.
Currently, low oil prices are decreasing the demand for biofuels, experts say. But the researchers say they’re confident the setback is temporary and their technology will facilitate the transition to a low-carbon economy after cheap oil loses its luster.
“When oil is cheap, it’s a very good fuel,” Blaylock says. “But at some point we have to make these decisions and say, is this sustainable?”
[Editor's note: The headline and lede of this piece has been updated to better reflect the diversity of research described in the story.]