Face it, cows know gas
Posted May 28th 2012 2:00PM
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Last year, Roderick Mackie, Professor of Animal Sciences at the University of Illinois, did some research on the way cows digest grass, raising hope that biofuels will eventually power our cars without compromising the world's food supply.
The study isolated microbes in a cow's gut that break through the tough cell walls of grass, allowing the animal to get at sugar inside.
That "grass energy" is the stuff of which biofuels like corn-based ethanol are made of. Moreover, unlike alternative fuels made from corn, ethanol made from switchgrass and other non-food crops doesn't eat into the world's food supply or drive up the cost of corn-based foods. Switchgrass, after all, is basically a weed - a prolific one at that.
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While ethanol derived from corn is currently used as an additive in gasoline to make "flex fuel," environmentalists call the practice unsustainable because of its negative effects on world corn prices - which, in turn, has an effect on humans' ability to, you know, not starve to death.
While making the switch to non-food plants such as switchgrass would protect valuable corn crops, the process is not yet economically viable. Currently, the cost of extracting the energy from the weed is simply too costly.
While the research into cow-like conversion hasn't hit on the exact combination of microbial enzymes needed to break down switchgrass, it has isolated just under 28,000 potential genes that unlock the soluble fermentable sugars that are in the plant cell wall. "The cow's been doing that for millions of years," explained Mackie.
For this unique research into the microbial life of the bovine rumen, researchers placed small, mesh bags containing switchgrass into a cow's rumen - the first component of its stomach - and examined the microbes that attached themselves to the grass after three days. Visual and chemical analyses showed that a specific community of microbes in the rumen breaking down the switchgrass. Scientist then conducted a genomic analysis of that bacteria and eventually identifed thousands of possible genes that adhered to the switchgrass. Some of these genes where then cloned and spliced into bacteria and more than 50 per cent of the proteins replicated demonstrated "enzymatic activity" against cellulosic plant material. It half worked, in other words.
The hope is that additional research will pinpoint the exact combination of enzymes that can then be used to make a second-generation of biofuels from switchgrass; a cost-effective alternative to corn-based ethanol.
Environmentalists and scientists, some of the biggest backers of alternative energy development, are also quick to caution that biofuels may result in more trouble than even the use of traditional fossil fuels. They point to concerns over the destruction of tropical rainforests in South America in order to grow corn for ethanol as well as the significant impact on global food supplies in general.
Mackie and other researchers see the switch to grasses and other non-food ethanol sources as a way of limiting those negatives. The solution is all the more urgent now that the U.S. Environmental Protection Agency (EPA) has given the green light to higher ethanol blends, a decision could see ethanol export leaders like Brazil ramp up their production - something critics charge could further intrude on the rain forests.
Currently, the U.S. EPA allows blends of up to 15 per cent ethanol in gasoline for cars and and light-duty trucks manufactured between 2001 and 2006 and all U.S. vehicles built since 2007. The U.S. EPA does not mandate the compatibility for automakers.
The Canadian government permits the use of a 10 per cent blend for gasoline-powered vehicles, and such "e" blends are available at a growing number of gas stations.
But the expanded and even the current level of corn-based ethanol threatens the environment, say critics. They point to the hundreds of thousands of acres that being planted with the crop specifically for fuel production. Some of that land was once rainforest.
Some scientists also assert that ethanol production still contributes to the greenhouse effect, something a move to switchgrass processing would eliminate. Consumer advocates also have a beef with corn ethanol, arguing it drives up the cost of crop for food producers, who have to compete with energy giants like Archer Daniels Midland.
A supply and demand side-effect is argued to be a bump up in the cost of putting bread on the table for families around the world, including those in impoverished areas of Africa.
No one makes bread out of switchgrass.
News Source: Evergeek
Photo Source: L. Brian Stauffer
