Corn Kernels Could Make Better Biofuels

The quest for better biomass fuels takes us to America’s heartland.
Keith Landry, Contributor

(Inside Science) -- Smog is choking air quality in large cities around the world. Thick smoke billows from factories. Cars clog highways and pump exhaust behind them. Scientists say greenhouse gases are raising air pollution to unhealthy levels.

Fossil fuels still power the industrial revolution but researchers hope renewable resources will soon power more of our planet, and save it. The quest for better biomass fuels takes us to America’s heartland. Corn is one of America’s biggest cash crops. Huge fields fill America’s heartland with rows of golden maize. We already use corn-based ethanol in our cars, but scientists want to create more-cost effective fuels from our nation’s natural resources.

In labs across the country, researchers are trying to engineer effective biomass fuels to meet America’s energy needs.

Jason Bice, at Purdue University, is doing his part. He believes the best biofuels of tomorrow could come from the skin that covers a tiny corn kernel. That coating is called pericarp and it is a key ingredient in ethanol.

“What pericarp is, is the shell of the corn. They fractionate the corn first. It’s milled and so the corn is already fractionated into a lot of pieces. It’s fractionated into starch, oil and its skin components. The pericarp is then separated out and then fed back through and they put enzymes into these patches of corn pericarp. And the enzymes digest the pericarp skin and they release from the pericarp starch, the cellulose,” said Bice.

That cellulose ferments and becomes a key component in ethanol. Researchers are working on ways to make that cellulose solution flow well with other liquids so we can pump it through pipes and into our gas tanks.

“As you introduce the cellulose and the starches into the system, you create a more complex fluid that creates a lot of pericarp. Right now we are trying to link different scales of what happens to the viscosity of the fluid to what happens as to the viscosity in the drop of the suspension,” said Bice.

Biomass engineers across America are working to find the perfect flow rate for tomorrow’s ethanol to make mass production easier.

“We are going to look at characterizing that fluid with an ultrasound spectrum. Basically, what that is, is it’s a tool that uses ultrasound to image how the fluid is moving within a rheometer,” said Bice.

Researchers have obstacles to overcome as they work on renewable fuels. Cost is one concern. Right now, researchers can make diluted biomass fuels with lots of water and low salt concentrations, but they need a better formula.

“It’s not cost-effective because in the end you have to take out that water through reheating. That costs a lot of money and takes a lot of energy,” concluded Bice.

Solving these problems will help scientists engineer renewable fuels that can compete with oil, gas and coal. It’s important work to move tomorrow’s ethanol industry from a tiny kernel of corn in the lab to an energy source that can fuel our planet’s clean energy needs.

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