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Corn Gene Boosts Biofuels from Switchgrass

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November 20, 2011 – Comments (4)

This is quite interesting. The picture in the article comparing the modified vs. unmodifed switchgrassis also striking.

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Corn Gene Boosts Biofuels from Switchgrass
ScienceDaily (Nov. 18, 2011)

http://www.sciencedaily.com/releases/2011/11/111118151414.htm

ScienceDaily (Nov. 18, 2011) — Many experts believe that advanced biofuels made from cellulosic biomass are the most promising alternative to petroleum-based liquid fuels for a renewable, clean, green, domestic source of transportation energy. Nature, however, does not make it easy. Unlike the starch sugars in grains, the complex polysaccharides in the cellulose of plant cell walls are locked within a tough woody material called lignin. For advanced biofuels to be economically competitive, scientists must find inexpensive ways to release these polysaccharides from their bindings and reduce them to fermentable sugars that can be synthesized into fuels.

An important step towards achieving this goal has been taken by researchers with the U.S. Department of Energy (DOE)'s Joint BioEnergy Institute (JBEI), a DOE Bioenergy Research Center led by the Lawrence Berkeley National Laboratory (Berkeley Lab).

A team of JBEI researchers, working with researchers at the U.S. Department of Agriculture's Agricultural Research Service (ARS), has demonstrated that introducing a maize (corn) gene into switchgrass, a highly touted potential feedstock for advanced biofuels, more than doubles (250 percent) the amount of starch in the plant's cell walls and makes it much easier to extract polysaccharides and convert them into fermentable sugars. The gene, a variant of the maize gene known as Corngrass1 (Cg1), holds the switchgrass in the juvenile phase of development, preventing it from advancing to the adult phase.

"We show that Cg1 switchgrass biomass is easier for enzymes to break down and also releases more glucose during saccharification," says Blake Simmons, a chemical engineer who heads JBEI's Deconstruction Division and was one of the principal investigators for this research. "Cg1 switchgrass contains decreased amounts of lignin and increased levels of glucose and other sugars compared with wild switchgrass, which enhances the plant's potential as a feedstock for advanced biofuels."

4 Comments – Post Your Own

#1) On November 20, 2011 at 2:18 PM, devoish (98.24) wrote:

Native Switchgrass is probably already competitive with petroleum as a biofuel, if not it just has to wait out petroleum price increases.

One of the major advantages of switchgrass is that it does not require tons of fertlizer to be productive. Almost nothing requires more fertilizer to grow than corn. All that midwest fertilizer does tremendous annual harm to the Gulf of Mexico as it washes down the Mississippi into the gulf in order to grow that corn.

Most Nitrogen fertilizer comes from natural gas.

Those plants are probably in potting soil with its added nitrogen and micronutrients, and may not do so well in native dirt. If that switchgrass requires as much more fertilizer as corn does to produce that much foliage (nitrogen contributes to foliage, potassium and phosphurus helps roots and fruits) any real advantage over corn may be lost.

At some point we will have to live within the limits of what nature can sustain.

To take a plant that is productive and adapted to native soil and modify it to demand more from the soil than the soil can deliver is not sustainable.

I like that the gene delays flowering, but staying in a  juvenile growth phase demands nutrition to grow.

Those are my first thoughts when I read the article. 

Best wishes,

Steven

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#2) On November 20, 2011 at 3:06 PM, binve (< 20) wrote:

devoish,

Those are all very good points. And I agree that the whole point of using switchgrass is that it grows natively without the soil being amended.

However, I don't necessarily agree with this:  Those plants are probably in potting soil with its added nitrogen and micronutrients, and may not do so well in native dirt.

Those studying switchgrass and advocating its use wouldn't make basic mistakes like that. 

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#3) On November 20, 2011 at 7:49 PM, devoish (98.24) wrote:

Those studying switchgrass and advocating its use wouldn't make basic mistakes like that.

Find out whats in the pots before you say that. :-)

I do not think it is a "mistake" to use potting soil to show the impact of the gene on growth early in a study. Switchgrass roots probably access at least 5 or 6 square feet of soil in search of nutrients outside of what looks from the pictures like at most 1 gallon pots. Using a "Miracle Grow" type product is the right thing to do too, no matter what is in the pots(leaving organic concerns aside for the moment). At some point later on you have to go to the expense of bringing in a native type soil, but not when you are at the stage that all you are trying to establish is the plant can get bushier.

But here's the thing. It is well known that open pollenated plants such as corn will crossbreed with non GMO varietys(switchgrass is also open pollinated). Now you have an open pollinated switchgrass crossbreeding with non gmo switchgrass. But the same gene that makes the sugars more accessible to fuels, maybe makes the switchgrass edible to corn borers. Once the gene is in native switchgrass you cannot call it back, and suddenly all the benefit of using switchgrass is lost because it now needs tons of pesticides to protect it from corn borers and costs a fortune.

Moving to ethanol and biofuels was smart. Choosing corn to do it with was not. Making switchgrass more like corn may not be smart either. Switchgrass is pretty good just the way it is. If you change the switchgrass, it is very likely to be a "zero sum" game in nature where something else has to pay the cost.

Even native switchgrass needs fertilizer to be productive as a fuel source, but that much bushier looking foliage does not come without additional nutrients from the soil which will deplete the soil faster.

At least I doubt it does.

Best wishes,

Steven

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#4) On November 21, 2011 at 9:59 AM, Turfscape (40.35) wrote:

>>But here's the thing. It is well known that open pollenated plants such as corn will crossbreed with non GMO varietys(switchgrass is also open pollinated). Now you have an open pollinated switchgrass crossbreeding with non gmo switchgrass.<<

Unless the genetic modification process is practicing male-sterile transgenics, creating what you could call "neutered" male plants whose pollen can't cross-breed and pass on the genetic marker. This is a practice that has become very standard throughout the Wilamette Valley in Oregon for cross-breeding grasses.

>>Even native switchgrass needs fertilizer to be productive as a fuel source, but that much bushier looking foliage does not come without additional nutrients from the soil which will deplete the soil faster.<<

That's not necessarily true. Part of the selective breeding would be identifying plants that more efficiently utilize the existing nutrients. It would be common for the researchers to be testing for nutrient uptake. They would most likely be using a controlled soil that was designed to mimic typical regional topsoil mixed with sphagnum peat, without added fertilizers. They would test the soil runoff after waterings and have both pre- and post- planting soil samples tested for content.

I'm basing this on standard turfgrass procedures used at the major agronomy schools (Penn State, Wisconsin, Michigan State). I haven't seen the actual testing methods used in this study...but, they're bound to be similar.

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