Cellulose is the major combustible component of non-food energy crops. Recently ways have been devised to turn it into bioethanol. An important step in a more widespread use of food-friendly biofuels.
But as it turns out, besides Brazil and the US, not many countries actually use ethanol as a transportation fuel. That’s why bioengineers at the Joint BioEnergy Institute in Emeryville, California set out, and with a little help from E.coli succeeded, in producing more commonly used fuels directly from cellulose.
With the help of a little bit of genetic engineering they managed to let E. coli produce the chemical precursors to gasoline, diesel and jet fuel. To achieve this they first created three E. coli strains to cut down cellulose and hemicellulose and then three different strains to be able to make the three different fuels. This means that per biofuel, only two different strains are needed.
Previously the same could be achieved but involved the production of many different varieties of expensive enzymes or needed bioethanol as an intermediate step making the process inviable as a competitor to fossil based transportation fuels. And often only one type of fuel can be produced with a certain process. By creating other strains, all of the most common transportation fuels can be made with the new technique.
Especially non-food crops and waste are suitable
In theory the technique can be used for biofuel production out of all crops. But due to their high starch content and consequently lower cellulose content, food crops are actually less suitable for the process than non-food crops. Even waste high in cellulose, like paper, could be used to produce any of the three fuels.
Unfortunatly so far it is only a very promising proof of concept, since the amount of fuel the bacteria produce is too low to be commercially viable. The next step is introducing the same genes into yeast, which is an industrially more useful organism. If they succeed the researchers may have actually created the first real biofuel production method that is as cheap or even cheaper than the use of fossil fuels.
© Jorn van Dooren | www.bitsofscience.org