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Plant sugars could rival petroleum with new extraction method

Researchers have hit on a discovery that could help clean up the world: a method for extracting plant sugars from trash like wood chips or corn cobs, then using it as a petroleum alternative.

Because it relies on waste material, the new technique could help solve two major environmental issues: the pollution caused by extracting and processing petroleum, and the trend of replacing food crops with crops intended for biofuels.

“To make greener chemicals and fuel, we’re working with plant material, but we don’t want to compete with its food value,” said Dr. Basudeb Saha, associate director of the Catalysis Center for Energy Innovation at the University of Delaware. “So instead of taking corn and extracting its sugars to make ethanol, we’re making use of the stalks and cobs left over after the corn is harvested, as well as other kinds of waste like wood chips and rice hulls.”

For decades, researchers have been looking into ways to recycle waste products into usable fuels and other products. However, biorefineries have come up against obstacles such as a lack of steady supply. In the case of plentiful waste like wood chips or corn cobs, the difficulty has been in finding a process that breaks them down so the plant sugars they contain can be used.

“The lignin that makes their cell walls so tough and sturdy acts like superglue, holding tightly to the sugars,” Saha said in a press release.

The current process requires two or more steps and relies on the use of harsh chemicals. But Saha, other University of Delaware researchers and scientists at Rutgers University have developed a much more environmentally friendly, single-step process for extracting plant sugars from waste materials.

Instead of pretreating wood chips to break down the lignin, then moving on the the hydrolysis of of the sugars within the cells, it comes both steps into one process. Using a concentrated, inorganic salt solution, the process also operates at a relatively low temperature – 185 Fahrenheit – and takes about one hour.

The University of Delaware team has filed for an international patent on their solution and process. They’ve even figured out how to recycle the salt solution.

“Our process enables – for the first time – the economical production of feed streams that could profoundly improve the economics of cellulosic bioproducts manufactured downstream, not to mention the environmental benefits of replacing petroleum,” Saha says. “More than 10,000 million metric tons of carbon emissions were reported in 2010 from conventional fossil fuels and chemicals, which has a long-term catastrophic effect on our environment.”

The team has published their research in the journal ChemSusChem.

By Kyla Cathey, staff writer

Image credit: Evan Krape, University of Delaware

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