A team of scientists led by researcher Christer Jansson of Berkley University is exploring a way to produce gasoline, diesel, and jet fuel from the plant. Their goal is to engineer tobacco plants that use energy from sunlight to produce fuel molecules directly in their leaves. The leaves would then be crushed, and the fuel extracted and separated. The scientists estimate that about 1000 acres of tobacco could yield about one million gallons of fuel.
Why tobacco? It’s grown in large tracts in more than 100 countries. It generates multiple harvests per year, its large leaves could store a lot of fuel, and it’s amenable to genetic engineering.
For the tobacco-to-fuels project, Jansson and his collaborators want to create a shortcut in the way in which solar energy is converted to biofuel.
Today, one approach to biofuel production requires deconstructing biomass and then using microbes to ferment them into fuel. In contrast, the team hopes to create a plant that grabs CO2 from the air and converts the carbon into a fuel that’s almost ready for the tank.
“We want to bypass downstream processes like fermentation and produce fuels directly in the crop,” says Jansson. “After the biomass is crushed, we could extract the hydrocarbon molecules, and crack them into shorter molecules, creating gasoline, diesel, or jet fuel.”
To get there, the scientists will work to create tobacco plants that are optimised to take in CO2, harvest sunlight, and produce hydrocarbon molecules. For the latter, Jansson will start with cyanobacteria genes that encode for enzymes which produce alkane, a type of hydrocarbon. He’ll then make synthetic versions of these genes for the tobacco. In another approach, Tasios Melis, a biologist, will conduct a similar exercise with green algae genes that produce isoprenoids, a type of hydrocarbon.
The scientists also want to get as much carbon into the tobacco plant as possible to maximise hydrocarbon production. Ordinary tobacco “fills up” with CO2 very quickly. To increase the plant’s carbon uptake, the team will insert cyanobacteria genes into the tobacco plants. They are very efficient at grabbing carbonate from the surrounding water and transporting it into the cell. The team hopes to grow their first plant in about 18 months.