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GM Switchgrass Could Boost Future Bio-Fuel Production

| Tuesday October 18th, 2011 | 0 Comments

Not so long ago, it seemed that biofuels were assumed to be the best means for us to wean ourselves from our oil addiction, with ethanol, in particular, attracting most attention as a putatively green-fuel. But then it became apparent that growing feed-stocks for biofuel production has some significant downsides – and perhaps now, electric vehicles have taken the spotlight as the antidote to oil.

Ethanol’s star fell for a couple of reasons. Production typically takes up land that otherwise would be used for food production – which, in turn, is bad for food prices. Then, experts started questioning whether ethanol production had any real environmental benefits to offer. One study conducted at Cornell University, found that the energy needed to produce corn-ethanol – the USA’s preferred feedstock for ethanol – may be up to 29% greater than the resultant energy in the bio-fuel itself. Why? Because heavy use of fertilizers to grow the corn, and the energy used to convert it to ethanol, both involve fossil-fuel energy.

So now, few seem to think corn-ethanol is the future. However, switch-grass has for a long time been regarded as a better feed-stock for ethanol production, and recent experiments by Berkeley biologist George S. Chuck suggest that the plant could become an important biofuel source, due to significant improvements in the potential energy yield of the plant.

The San Francisco Chronicle reported last week that Mr Chuck has taken a fast growing variety of switch-grass and genetically modified it by introducing a corn gene; resulting in a doubling of the starch content of the crop. The starch content is important, because the sugars derived from the starch – when fermented – produce ethanol; simply stated, more starch equals more ethanol.

As well as inducing a higher starch content, the introduction of the corn gene effectively keeps the modified switch-grass young, which appears to have two further benefits. First of all, it prevents the grass from flowering – so the risk of cross pollination with native species is removed. Secondly, plant lignin – the organic polymer which makes switch-grass very tough – is less prevalent in the engineered variety, which allows chemical treatment to be avoided before turning the crop into ethanol.

But even in it’s native form, switch-grass has other inherent attributes which make its cultivation compelling as a fuel source. It grows fast, and its root systems penetrate about as deep into the ground as the crop is tall. The substantial roots help prevent soil erosion, while the crop only needs replanting every 10 years. Deep roots also allow the plant to access deep soil water, which switch-grass uses efficiently. And since it has evolved over millions of years, it’s highly adaptable to all sorts of climates, and can thrive in depleted soils – with less fertilizer use – where other crops are difficult to grow.  Switch-grass replenishes organic soil matter too, so it can even help restore farmland. Corn cultivation offers none of these benefits.

Mr Chuck is planning further experiments to attempt to ‘turn on’ other genes in response to light and dark, and to raise the starch content even higher – all in the effort to increase the potential energy density of the crop.

Although these developments are years away from commercialization, the results appear promising. But genetic modification, of course, has its detractors. The fact that the plant is kept young, and doesn’t flower, no doubt means it cannot be re-seeded and therefore can only be replanted by buying seed from the company that will ultimately own the intellectual property (IP). The potential for big business to control bio-fuel energy is obvious – but that’s always been the nature of energy production, past, present and likely, future too.

Of course, GM crops are already mainstream and it’s something the likes of  Monsanto is always criticized for, especially when it comes to food production;  Big agribusinesses owning genetic codes, potentially creating mono-cultures, and locking farmers into doing business with them on an ongoing basis. Consumers are also concerned about the lack of GM food labeling laws and question the possible health effects. But food is not the subject here.

Perhaps GM crops create less public backlash when we’re talking about ones that we’ll be using to produce fuel?  But no doubt, to many, whether we’re growing fuel or food, GM crops are anathema from a sustainability perspective. Last week,  TriplePundit published a piece that suggests the more sustainable approach is to take the organic bio-fuels route. But will organic switch grass hold the same energy density as the new corn-gene-spliced switch-grass?

If the goal is to maximize the potential of bio-fuels as a way to produce oil substitutes, and reduce overall carbon emissions, is the science of genetic modification a reasonable trade-off, if it yields more ethanol per acre without heavy fertilizer use and without the risk of cross pollination?

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