When most people think about renewable energy and sustainable food sources, they imagine solar panels and wind turbines, low-impact agriculture and local foodsheds.
Y.H. Percival Zhang sees carbohydrates.
Using carbohydrates, Zhang has found ways to inexpensively produce hydrogen to power cars and a mechanism to turn any plant into a food source. In carbohydrates, Zhang sees food, fresh water, biofuels, nutrients, and renewable materials.
“What we are doing in my lab is revolutionizing the biotechnology paradigm to come up with solutions that could help solve some of the biggest challenges facing our planet,” said Zhang, an associate professor of Biological Systems Engineering in the College of Agriculture and Life Sciences and the College of Engineering. “I propose what I am calling the ‘electricity-hydrogen-carbohydrate cycle’ to jump-start sustainability efforts around the world.”
Two of Zhang’s projects involving the manipulation of carbohydrates have received an enormous amount of attention around the world. One paper he published highlights how he has been able to extract large amounts of hydrogen from any plant, a breakthrough that has the potential to bring a low-cost, environmentally friendly fuel source to the world.
“Our new process could help end our dependence on fossil fuels,” he said. “Hydrogen is one of the most important biofuels of the future.”
On the surface, hydrogen fuel might not seem to have much to do with creating a new food source, but Zhang used an extraction process similar to the method he employed for hydrogen to come up with a novel way to manufacture one of the main components of the human diet.
Zhang recently published a paper in the Proceedings of the National Academy of Sciences of the United States of America that demonstrates how he has been able to create starch from plants not traditionally thought of as a food source. This would allow farmers to grow a large amount of biomass on marginal lands for food and biofuel without requiring fertilizers, pesticides, and massive amounts of water.
All this revolutionary work involves a pot of enzymes.
“Both of these breakthroughs are based on the use of numerous purified enzymes in one pot for implementing unnatural reactions,” Zhang said. “We call it ‘cell-free biosystems for manufacturing’ or ‘cell-free biomanufacturing.’ ”
Zhang uses a variety of enzymes produced by the bacterium E. coli and mixes together ones not usually found together in nature.
In the fuel project, Zhang’s team liberates high-purity hydrogen under mild reaction conditions at 50 degrees Celsius and normal atmospheric pressure. The biocatalysts used to release the hydrogen are a group of enzymes artificially isolated from different microorganisms that thrive at extreme temperatures, some of which could grow at around the boiling point of water.
To extract the hydrogen, the researchers manipulate xylose, a sugar that makes up as much as 30 percent of plant cell walls.
To free the hydrogen, Virginia Tech bioengineers separated a number of enzymes from their native microorganisms to create a customized enzyme cocktail that does not occur in nature. The enzymes, when combined with xylose and a polyphosphate, liberate the unprecedentedly high volume of hydrogen from xylose, resulting in the production of about three times as much hydrogen as other hydrogen-producing microorganisms.
Enzymes also are critical for Zhang’s project with starch.
His new approach takes cellulose from nonfood plant material, such as corn stover, and converts about 30 percent to amylose, a component of starch. Corn stover consists of the stem, leaves, and husk of the corn plant remaining after ears of corn are harvested. However, the process works with cellulose from any plant. This process has the highest sugar utilization efficiency. During the process, the cellulose is also hydrolyzed into glucose, which can used for ethanol production.
This bioprocess is easy to scale up for commercial production. It is environmentally friendly because it does not require expensive equipment, heat, or chemical reagents and does not generate any waste. The key enzymes immobilized on the magnetic nanoparticles can easily be recycled using a magnetic force.
His processes have a host of other potential uses, including biodegradable packaging, food for livestock, and a battery that runs on sugar.
Now that Zhang has made two big discoveries, he’s focusing on ways to bring them to the market, where they can start to benefit society.
“I’d like to improve these technologies and solve the remaining technical issues so that we can achieve large-scale commercialization,” he said.
His goal, quite simply, is to make history.
“I want to follow in the footsteps of Henry Ford and Thomas Edison, who transformed the world through their inventions and innovations.”
Some of Y.H. Percival Zhang’s research has already reached the marketplace and is making a difference in local economies.
In 2011, OptaFuel announced that it would build a pilot plant in Southwest Virginia to test Zhang’s research that involves extracting cellulose from plants and turning it into energy. OptaFuel’s parent company, Biomethodes, licensed Zhang’s technology, which brings money back to Virginia Tech and the commonwealth.
The Virginia Tobacco Indemnification and Community Revitalization Commission approved more than $2.5 million to build the pilot plant in the first year of the three-year project. Biomethodes is providing additional first-year funds. About $10 million more in funding is expected in the coming years, which Biomethodes will match. As the project grows, so will its economic impact on the area.
“When you also consider the indirect jobs we will help create in construction, timber, and other fields, we could have a significant impact on the region.” said OptaFuel CEO Anthony Scime.
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