Scientists find bugs that eat waste and excrete petrol

Tuesday, June 17th, 2008

Scientists find bugs that eat waste and excrete petrol — or, rather, they create them:

Inside LS9’s cluttered laboratory — funded by $20 million of start-up capital from investors including Vinod Khosla, the Indian-American entrepreneur who co-founded Sun Micro-systems — Mr Pal explains that LS9’s bugs are single-cell organisms, each a fraction of a billionth the size of an ant. They start out as industrial yeast or nonpathogenic strains of E. coli, but LS9 modifies them by custom-de-signing their DNA. “Five to seven years ago, that process would have taken months and cost hundreds of thousands of dollars,” he says. “Now it can take weeks and cost maybe $20,000.”

Because crude oil (which can be refined into other products, such as petroleum or jet fuel) is only a few molecular stages removed from the fatty acids normally excreted by yeast or E. coli during fermentation, it does not take much fiddling to get the desired result.

For fermentation to take place you need raw material, or feedstock, as it is known in the biofuels industry. Anything will do as long as it can be broken down into sugars, with the byproduct ideally burnt to produce electricity to run the plant.

The company is not interested in using corn as feedstock, given the much-publicised problems created by using food crops for fuel, such as the tortilla inflation that recently caused food riots in Mexico City. Instead, different types of agricultural waste will be used according to whatever makes sense for the local climate and economy: wheat straw in California, for example, or woodchips in the South.

Using genetically modified bugs for fermentation is essentially the same as using natural bacteria to produce ethanol, although the energy-intensive final process of distillation is virtually eliminated because the bugs excrete a substance that is almost pump-ready.

The closest that LS9 has come to mass production is a 1,000-litre fermenting machine, which looks like a large stainless-steel jar, next to a wardrobe-sized computer connected by a tangle of cables and tubes. It has not yet been plugged in. The machine produces the equivalent of one barrel a week and takes up 40 sq ft of floor space.

However, to substitute America’s weekly oil consumption of 143 million barrels, you would need a facility that covered about 205 square miles, an area roughly the size of Chicago.

That is the main problem: although LS9 can produce its bug fuel in laboratory beakers, it has no idea whether it will be able produce the same results on a nationwide or even global scale.

“Our plan is to have a demonstration-scale plant operational by 2010 and, in parallel, we’ll be working on the design and construction of a commercial-scale facility to open in 2011,” says Mr Pal, adding that if LS9 used Brazilian sugar cane as its feedstock, its fuel would probably cost about $50 a barrel.

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