Carbon-negative biofuels

Science magazine weighs in

Posted by Maywa Montenegro (Guest Contributor) at 2:37 PM on 08 Dec 2006

Yesterday I came across a head-turning new biofuels study by researchers at the University of Minnesota that found that planting a mixture of native grassland perennials produces biofuels more efficiently than corn and soybeans (no surprise) and even more efficiently than any single-grass plots (hmm, interesting).

According to team leader David Tilman, the most diverse plots produced 238 percent more bioenergy yield than the average plot containing a single species.

As I was going back to post on this, however, I saw that biofuels made the cover of Science this week, due to back-to-back publication of the above study and one on carbon-negative biofuels. The latter describes efforts by researchers at MIT, the Whitehead Institute, and the Berlin Institute of Technology to engineer yeast with increased tolerance and production of ethanol. The outcome, the authors project, will be that ethanol could go from being highly resource intensive (and net carbon positive) to "carbon-negative."

I have a lingering question, which I didn't see addressed in the abstracts: does this research apply equally to corn-based ethanol and cellulosic ethanol? Because while this could be a great boon to cellulosic production, I am afraid that any improvement in the corn ethanol process will just fan the flames of its supporters. Because ethanol is ethanol no matter from whence it derives, I have a feeling it could be applied to both processes ... which of course puts the onus on us to devote these engineered tools to the best of the biofuels. As the first study points out, the "best" is clearly not corn or soybeans, but grasses -- most likely a patchwork quilt of them.

For story: Carbon-negative biofuels
4 Comments | Post a Comment

I just read both articles

They didn't make it clear but it should apply to both types of production. The yeast eats starch (or sugars) and gives off ethanol as a waste product but eventually dies in its own waste. The idea is to give them greater tolerance to ethanol so they can survive to produce more of it. If successful, it will lower the cost of ethanol because you will get more ethanol from the same amount of yeast which will use less energy (which will also make it less carbon intensive).

The difference between cellulosic and corn ethanol production is basically that corn starch is easy to turn into sugar but cellulose is not. But, once you get the sugar, both methods then use yeast to ferment the sugar (it eats the sugar and craps ethanol). This last part of the process is the same for both methods.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

by biodiversivist at 6:11 PM on 08 Dec 2006

Science articles

Thanks, BioD. That is what I figured. Nice to hear that you're already on top of these new research papers and that (from what I gather from your postings) we're on the same wavelength.

by Maywa Montenegro at 7:48 PM on 08 Dec 2006
[ Parent ]

Science sends an email

with a link to the online magazine for subscribers. I usually read it on line. I go narcoleptic when I try to read the paper version.

In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world

by biodiversivist at 9:34 PM on 08 Dec 2006

are you sure ?

I'm was under the impression that prairie grasses are only useful as biomass for cellulosic ..I highly doubt grass has the same easily accessed sugar's that products like corn and sugar-cane have

by Orfintain at 5:52 PM on 17 Dec 2006

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