Better Bug to Make Cellulosic Ethanol

MIT Technology Review
Tuesday, September 09, 2008

A new strain of bacteria could make cellulosic ethanol cheaper.
By Prachi Patel-Predd

New genetically modified bacteria could slash the costs of producing ethanol from cellulosic biomass, such as corn cobs and leaves, switchgrass, and paper pulp. The microbes produce ethanol at higher temperatures than are possible using yeast, which is currently employed to ferment sugar into the biofuel. The higher temperature more than halves the quantity of the costly enzymes needed to split cellulose into the sugars that the microbes can ferment. What's more, while yeast can only ferment glucose, "this microorganism is good at using all the different sugars in biomass and can use them simultaneously and rapidly," says Lee Lynd, an engineering professor at Dartmouth College, who led the microbe's development.

Most of the ethanol produced in the United States is made from corn. But making the biofuel from corn takes a lot of energy and competes with agricultural uses of the crop. Making fuel from cellulosic plant matter has the potential to be much more sustainable. However, cellulosic-ethanol production is still too expensive to be commercially competitive with corn ethanol.

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