Researchers in Spain have genetically modified tobacco plants of the Virginia Gold and Havana 503B commercial cultivars to increase the plant’s production of starch and sugars, which is used to produce ethanol.
According to professor Jon Veramendi, head of the plant agrobiotechnology research group, growing these genetically modified tobacco plants as a source of biomass for producing bioethanol could be an alternative to traditional tobacco growing, which is in decline in the United States and in Europe.
He noted that traditional tobacco growing allows the plant to develop and the leaves to grow larger as the nicotine is synthesized when the plant is more mature. However, results from the research found that the modified plants were phenotypically equivalent to their wild types, yet showed increased starch (up to 280%) and soluble sugar (up to 74%) contents in leaves relative to their control plants. Fermentable sugars released from the stalk were also higher (up to 24%) for transplastomic plants.
“The tobacco plants are sown very close to each other and various mowings are made throughout the cycle,” he said. “When the plant has grown to a height of about 50 cm, it is cut and the output is taken to the biomass processing facility. In this way, it is possible to obtain up to 160 metric tons of matter per hectare over the whole cycle.”
Veramendi said that when the tobacco is integrated into a biorefinery, it is possible to extract useful by-products, such as proteins to feed humans or animals – proteins constitute up to 30% of the dry weight of the plant and are nutritionally more complete and have a greater efficiency rate than those from cow’s milk or soya. Solatenol, which is used to produce vitamins E and K, and xanthophyll, an additive in chicken feeds, also can be extracted from the modified tobacco plants.