Everybody’s Science
What's New with Wheat
By Sandy Miller Hays, Agricultural Research Service

Plant physiologist Gregory Glenn prepares to make wheat-starch biodegradable containers.

Gooey cinnamon rolls, colorful birthday cakes, freshly baked bread, pizza—it's definitely fun to daydream a little about all the nice things you can make with wheat. Here's something new to add to the list: "clamshells."

We're not talking here about the "portable housing" used by actual clams, but those lightweight, hinged containers that some restaurants use to pack up your take-home goodies. They're commonly called "clamshells" because that's what they look like—the natural architecture of clams—and they're typically made of polystyrene.

That could change in the future, though, thanks to an Agricultural Research Service scientist who's figured out how to make these food containers out of an important component of food itself: wheat.

Why worry about these clamshells? Think about how many billions of burgers and other food items get packed into these containers, which ultimately wind up in landfills that are already overloaded. And we've all observed that polystyrene doesn't break down quickly, so making the containers out of biodegradable ingredients would certainly be good news for the environment.

The ARS scientist, based in Albany, Calif., has been working with a California company to make these types of containers out of the world's most widely planted grain: wheat. His wheat-starch-based prototypes are sturdy, look nice, work well and are just as leakproof as the polystyrene versions.

So how do you turn wheat starch into a burger box? It's simple, says the scientist. First, you pour the wheat-starch batter into big presses or molds that work like a giant waffle iron. The mold is closed and locked, and the moisture from the batter creates steam that causes the batter to foam, expand and fill the mold. The steam is vented and the molded wheat-starch mixture is "baked"—all in less than a minute from start to finish.

The waterproofing comes from a coating that's added later, to help the container keep its strength and form if it's holding something moist. But when that container hits the landfill, it breaks down in just a few weeks.

This particular ARS scientist is an old pro at coming up with innovative uses for wheat starch. One of his past successes has been turning the starch into a light-weight concrete that could be used for decorative garden items, roofing tiles, insulation, flooring, benches, fountains, or even exterior panels for high-rise office buildings.

The wheat starch forms what the scientist calls an "aquagel" that acts as a durable aggregate for mixing with cement. He says the wheat-based aquagel would probably require less energy and labor to produce than other aggregates.
His recipe is simple: Heat a mixture of wheat starch and water, then pour it into a mold and let it cool to form a gel. Air-dry the gel until it's hard, transparent and brittle. Then it's milled or ground into white particles similar to coarse sand.
Next, the particles are soaked in water for several hours, then rinsed and drained, leaving a tough, rubbery aquagel aggregate that's 25 percent starch, 75 percent water. Add it to cement, and voila! you wind up with wheat-based concrete.

The scientists at that ARS lab at Albany are real wizards at turning agriculture's leftovers into useful, environmentally friendly products. For example, another scientist there has worked on turning wheat straw and rice straw into packing materials, such as the molds that hold delicate computers and electronic equipment snug in their shipping boxes—again replacing the current polystyrene with a biodegradable alternative. The idea is to turn a slurry of straw, water and additives, such as clays and starches, into dried and molded rigid forms.
This technology could give farmers a whole new market for straw that is now plowed under the soil or sold for animal feed or bedding. And it could be a big market, too; in California alone, the rice crop each year generates more than 300,000 tons of straw, and California's wheat crop produces an estimated 400,000 tons of straw.

Sounds like Rumplestiltskin isn't the only one who knows how to turn straw into gold!

Holding It All Together—With Bacteria

It's a lesson we all learned early at Mom's knee: Bacteria are bad, soap is good.
But in fact, there are some bacteria who don't automatically classify as the bad guys. According to an Agricultural Research Service scientist in Madison, Wis., some bacteria might wind up helping us—and the environment—in amazing ways.
Bacteria are a lot like that old dance "The Hokey-Pokey"—they're in, out and all about. One place they're definitely "in" is the digestive systems of cows and other animals that eat grass and plants. These tiny microbes help the animals break down the tough fiber in their diets.

The ARS scientist found that the microbes' sticky outer coating could be the ideal basis for a new biologically based wood glue. Produced by fermentation, this adhesive residue could be used to produce wood products such as plywood and particleboard.

The ARS scientist worked with collaborators in the U.S. Forest Service to come up with a way to combine strains of the bacteria, called Ruminococcus, and scrap plant material—everything from crop residues to recycled newspapers—to make a sticky fermentation residue that really gets a grip.

This all-natural residue could replace some of the petroleum-based phenol-formaldehyde (PF) residue that's now used to bond multiple layers of wood together. The end result: a safer and more environmentally friendly adhesive.
The ARS scientist came up with the idea while studying the bacteria that live in cows' digestive tracts (and you thought a career in science would be boring!). He noticed that certain bacteria that digest cellulose—Ruminococcus and Clostridium among them—really cling to plant material. These bacteria have a outer slime layer—we call it "glycocalyx" in polite society—that allows them to cling to a surface, much like bacteria cling to your teeth to cause cavities.

The scientist says these bacteria-based residues could replace up to 45 percent of the traditional adhesive used in wood products, and even stand up to moisture. Plus, these natural adhesives could be produced at very little cost as a byproduct of ethanol production, giving a little extra incentive for developing the processes that make it possible to turn plants into fuel.
Incidentally, the ARS scientist and his Forest Service colleagues have filed for a patent on this research, so the technology is now available for licensing, in case there are any enterprising companies out there that would like to get in on this particular ground floor.

Actually, this is hardly the first time ARS scientists have found that "bacteria can be beautiful." A few years back, an ARS scientist in North Carolina showed that a particular bacterium with the picturesque name Azobacter vinelandii can do at least two important tasks.

First of all, they can help plants "fix" nitrogen. A bit of explanation here: "Fixing" nitrogen doesn't mean the nitrogen was "broken" in some way. Instead, nitrogen fixation is a process in which plants can take nitrogen from the atmosphere and turn it into a form of natural fertilizer to boost the plants' growth. Plants rely on soil bacteria to help this process along, and most bacteria in turn need a soil nutrient called molybdenum to make this magic happen. In fact, until 1980, most scientists said molybdenum was a "must" for nitrogen fixation—but therein lay a problem, because in many soils of the southeastern U.S., the molybdenum was tied up in a form that the bacteria couldn't use.

The ARS scientist was the first to show that molybdenum unavailability wasn't necessarily a deal-breaker, by demonstrating that Azobacter vinelandii could fix nitrogen without benefit of molybdenum. He and his colleagues have since found other bacteria that can do the same thing. This means these bacteria could be used to boost nitrogen levels in the soil—naturally, without man-made fertilizer—and boost the fertility of our crops in those fields where molybdenum is missing in action. What's more, these bacteria also release hydrogen, which could conceivably be collected and used as a biofuel.

Hmmm—it sounds like some bacteria have been getting a bad rap from Mom all these years!

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