Rock Doc: Training microbes to make biofuel
By E. Kirsten Peters, College of Agricultural, Human & Natural Resource Sciences
PULLMAN, Wash. – When you fill your tank, you likely see a little sticker on the pump saying part of the fuel is ethanol. Ethanol is a biofuel, which means it comes from plants like corn rather than from fossil fuel – ancient carbon that’s been buried within the Earth for millions of years.
Producing more biofuels is on the agendas of governments and private industry alike. Biofuels can potentially help nations become more energy independent. If a country can grow plants and produce biofuels from them, that nation could potentially import less crude oil.
Biofuels, if done right, also could reduce the total amount of greenhouse gas emissions produced in the transportation sector.
Burning precious food crops
But there are drawbacks, at least with corn-based ethanol. For one thing, using ethanol in our vehicles means we are essentially burning food as we tootle down the road. Food is pretty precious stuff in a hungry world, so a number of people are worried about corn-ethanol.
It also takes considerable petroleum-based fuel to grow corn, harvest it and process it into ethanol. So researchers around the world are on the lookout for better ways to make biofuels.
Biodiesel is another biofuel that you’ve likely heard something about. It’s blended into petroleum-based diesel to power trucks and diesel-fueled cars.
Biodiesel is quite simple to make from vegetable oil. In freshman classes, I’ve led students to make it in small batches. But if biodiesel is made from oils we eat, it has some of the same drawbacks as corn-based ethanol.
E. coli makes diesel-like fuel
Recently there was an interesting report about an advance made by scientists researching a new approach to making biodiesel. A team of researchers used genetically modified E. coli bacteria to convert sugar into a material very similar to petroleum-based diesel fuel.
The fuel produced is so much like petroleum diesel, it can be used at full strength in engines.
Professor John Love, a synthetic biologist at the University of Exeter, was one of the scientists involved in the work. Talking with a reporter from BBC News, he said, “What we’ve done is produced fuels that are exactly the chain length required for the modern engine and exactly the composition that is required.”
Some people fear bioengineering when it comes to the food we eat, but there might be less resistance to the approach if it is used to produce fuel rather than vittles.
Three to five years to determine merit
But there is more work to be done. E. coli doesn’t produce a lot of fuel. According to the BBC news report, it would take more than 100 quarts of E. coli to produce a teaspoon of diesel fuel.
“Our challenge is to increase the yield before we can go into any form of industrial production,” Love said. “We’ve got a timeframe of about three to five years to do that and see if it is worth going ahead with it.”
The devil is in the details when it comes to biofuels developed so far. But don’t count researchers out – there are many good ideas being pursued all around the world.
Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human and Natural Resource Sciences at Washington State University.