Ruth Sanz-Barrio has demonstrated, for the first time, the viability of using specific tobacco proteins (known as thioredoxins) as biotechnological tools in plants increasing the amount of starch produced in the tobacco leaves by 700% and fermentable sugars by 500%.

Barrio, an agricultural engineer of the NUP/UPNA-Public University of Navarre and researcher at the Institute of Biotechnology the mixed center of the CSIC-Spanish National Research Council, Public University of Navarre and the Government of Navarre, reports her work in her PhD thesis.  “We believe that these genetically modified plants could be a good alternative to food crops for producing biofuels, and could provide an outlet for the tobacco-producing areas in our country that see their future in jeopardy owing to the discontinuing of European grants for this crop,” she said.

Ruth Sanz-Barrio PhD. Click image for the largest view.

Ruth Sanz-Barrio PhD. Click image for the largest view.

Thioredoxins (Trxs) are small proteins present in most living organisms.  Barrio demonstrated the capacity of the thioredoxins f and m in tobacco as biotechnological tools not only to increase the starch content in the plant but also to increase the production of proteins like human albumin. “For some time Trxs have been known to have a regulating function in living organisms, but in the thesis we have shown that they can also act by helping other proteins to fold and structure themselves so that they become functional.”

Tobacco has been subject to intense research including genetic modification for rabies antibodies, environmental toxin cleanup, and pharmacological efforts to make medications.  Non-engineered tobacco and nicotine are being investigated as natural organic pesticides.  Tobacco does have a useful future.

The human albumin matter is of such importance it may drive lots more tobacco production.  Human albumin is the most widely used intravenous protein in the world for therapeutic purposes. It is used to stabilize blood volume and prevent the risk of infarction, and its application in operating theatres is almost a daily occurrence. It is also used in burns, surgical operations, hemorrhages, or when the patient is undernourished or dehydrated, and in the case of chronic infections and renal or hepatic diseases.

For now commercial albumin is extracted from blood and the lack of a sufficient volume in reserve has prompted many researchers to seek new formulas for obtaining this protein on a large scale economically and safely.  Barrio notes, “We have come up with an easier, cheaper procedure for producing it in the tobacco plant and extracting it. By fusing the genes encoding the Trxs f or m, we increased the amount of recombinant protein (the albumin, in this case). We also managed to improve the solubility and folding of the albumin, which helps to extract it from the plant and lowers the costs involved in this process.”

The biofuel production part began as the research progressed.  Thioredoxin f was shown for the first time in vivo to be more efficient than Trx m in regulating the metabolism of carbohydrates, as it causes “a significant increase in the amount of starch in the leaves, which can reach 700% with respect to the amount obtained from non-modified control plants.”  Barrio explained that this was also new, since “up until now both Trxs were thought to act in the same way, but we have shown that this is not so.”

Once the regulating function of Trx f in starch synthesis had been proven, Barrio focused on its possible application in energy crops used to produce bioethanol: “We saw that the leaves of the genetically modified tobacco plants were releasing 500% more fermentable sugars. With these sugars, which could later be turned into bioethanol, one could obtain up to 40 liters of bioethanol per metric ton of fresh leaves – according to the theoretical calculation provided by the National Center for Renewable Energies where the enzymatic test was conducted – which would mean an almost tenfold increase in bioethanol yield with respect to the control tobacco plant that had not been modified.”

The genetically enhanced tobacco could be an alternative source of biomass in areas like Extremadura and Andalusia, Spain’s traditional tobacco producing areas. The estimated calculations of the starch production of these enhanced varieties would be the equivalent to those of crops like barley or wheat. “As cereals are currently being used as the raw material to produce bioethanol, genetically enhanced tobacco could be an alternative source of biomass and for obtaining clean energies,” she said.

Barrio’s research does give tobacco research quite a boost.  Biofuel and albumin are huge markets compared to the niches noted and the others out there not mentioned.  Aside from smoking, snuff and chewing the tobacco market is rather small.  Rolled out into markets like biofuel and major pharmaceutical products the research would be a major revitalization of a lot of farmers and their communities as well as contribute an alternative fuel to the consumer market.


1 Comment so far

  1. Matt Musson on October 17, 2013 8:58 AM

    It is important to remember that tobacco is one of the most energy and labor intensive crops around. Growing specialty protiens would be viable. But, growing tobacco for biofuels is crazy. The cost of inputs would mean you could never break even.

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