Tobacco is a high-density crop that is mowed several times throughout its cycle and that can be a good thing, because it can produce as much as 160 tons of fresh biomass per hectare.

Biomass that is suitable for producing bioethanol.  Smoking cigarettes is bad but renewable energy is good, tobacco just needs some help from science.

For a recent study, tobacco plants of the Virginia Gold and Havana commercial cultivars were genetically modified to increase their production of starch and sugars, which contributes to the increase in ethanol production. Traditional tobacco growing allows the plant to develop and the leaves to grow and get bigger, as the nicotine is synthesized when the plant is more mature. However, if the plants are used for producing biofuels, the researchers go for a higher-density crop similar to that of forage crops.

As Professor Jon Veramendi of Elhuyar Fundazioa  explained, "What has been done now is fieldwork with these two tobacco cultivars and it has been found that the starch and sugars in the tobacco leaf are in fact higher. The tobacco plants are sown very close to each other and various mowings are made throughout the cycle. When the plant has grown to a height of about 50 cm, it is cut and the output is taken to the biomass processing factory. That way, it is possible to obtain up to 160 tonnes of matter per hectare over the whole cycle."

When the tobacco is integrated into a biorefinery, it is possible to extract interesting by-products like proteins (they constitute up to 30% of the dry weight of the plant and are nutritionally more complete and have a greater protein efficiency rate than those from cow's milk or soya, so they could be used to feed humans or animals), solasenol (used to produce vitamins E and K) and xanthophylls (an additive in chicken feeds).

Over the last ten years, the surface area devoted to tobacco growing has been cut in Europe by 45%. In Spain, the main tobacco-growing area is Extremadura, followed by Andalusia. The researchers consider that one of the alternatives to the traditional use of tobacco could be to produce biofuel. Next, high-density cultivation tests will need to be carried out to see whether the results obtained in the fieldwork, where the cultivated surfaces are very small, are confirmed. 



Published in
Molecular Breeding.
Source: Elhuyar Fundazioa