US researchers increase tobacco's oil production for biofuel use

January 3, 2010 A team of researchers from the Thomas Jefferson University's Biotechnology Foundation Laboratories (BFL) in the United States have managed to increase the amount of oil produced by tobacco leaves. Tobacco oil can be very efficiently converted to biofuel, but most oil is located in the seeds, which the plant does not produce many of.

Tobacco seeds produce around 40% oil per dry weight but a crop of the plant yields only around 600kg of seeds per acre. The leaves have an oil content of around 1.7–4% oil per dry weight. The oil has previously been tested for powering diesel-fueled vehicles and can be more efficiently converted than the product of many other crop plants.

The team from BFL identified that oil production in the leaves was controlled by two genes: the diacyglycerol acytransferase (DGAT) and the LEAFY COTYLEDON 2 (LEC2) genes. By genetic engineering, they achieved oil yields of 5.8% oil per dry weight by modifying the DGAT while changes to the LEC2 resulted in a yield of 6.8% per dry weight.

"Tobacco is very attractive as a biofuel because the idea is to use plants that aren't used in food production," said cancer biology assistant professor at Thomas Jefferson Dr Vyacheslav Andrianov, Ph.D. "In some instances, the modified plants produced 20-fold more oil in the leaves."

Various efforts are being made to find biofuel sources that are not also potential food, in order to steer clear of causing further rises in global food costs. Last month the US government anounced funding for research that used nonphotosynthesising micro-organisms to manufacture biodiesel, in the hope that this will prove more efficient than options that rely on photosynthesis. This also escapes one criticism of biofuels like tobacco; that competition for land to grow crops on will result in biofuel crops displacing foodstuffs and pushing food prices up. In November 2009 a Spanish team launched a study to determine if tobacco, as well as the prickly pear, was capable of withstanding the harsh conditions of land not suitable for growing food, selecting these plants for their ability to survive water shortages.