Brian Westenhaus pulls back the curtain on a new combined approach to bioenergy and biofuels:
MSU microbiologist Gemma Reguera an AgBioResearch scientist has developed bioelectrochemical systems known as microbial electrolysis cells, or MECs using bacteria to breakdown and ferment agricultural waste into ethanol.
Reguera’s platform is unique because it employs a second bacterium, which, when added to the mix, removes all the waste fermentation byproducts or nonethanol materials and generates electricity.
Similar microbial fuel cells have been subjects for investigation before. But the maximum energy recoveries from corn stover, the common feedstock in the U.S. for biofuels, stalls at around 3.5 percent. Reguera’s platform, despite the energy invested in chemical pretreatment of the corn stover, averaged 35 to 40 percent energy recovery just from the fermentation process, said Reguera.
Reguera explains the huge productivity increase with, “This is because the fermentative bacterium was carefully selected to degrade and ferment agricultural wastes into ethanol efficiently and to produce byproducts that could be metabolized by the electricity-producing bacterium. By removing the waste products of fermentation, the growth and metabolism of the fermentative bacterium also was stimulated. Basically, each step we take is custom-designed to be optimal.” The second bacterium, Geobacter sulfurreducens, generates electricity. The electricity, however, isn’t harvested as an output. It’s used to generate hydrogen in the MEC to increase the energy recovery process even more. Reguera said, “When the MEC generates hydrogen, it actually doubles the energy recoveries,” she said. “We increased energy recovery to 73 percent. So the potential is definitely there to make this platform attractive for processing agricultural wastes.” _Brian Westenhaus
MSU news release
Green Car Congress coverage
Article abstract from Environmental Science & Technology
Full PDF research article (via New Energy and Fuel)
Time will tell how much impact this discovery will have on energy markets at large. It will take a great deal of time to make these processes more robust, and to scale them to commercial size. In the meantime, cheap natural gas is slated to enjoy at least 10 - 20 years of market supremacy as a crude oil substitute.
We at Al Fin wish the girls of MSU good luck, and many happy discoveries!
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