A fungus may turn agricultural waste into bioenergy

15 July 2012 Yue Wang With the increasing popularity of ethanol, the biofuels industry is looking for more materials to increase production. A new study says a lowly fungus called white rot may offer a solution. Currently, the bioethanol industry…

15 July 2012

Yue Wang

With the increasing popularity of ethanol, the biofuels industry is looking for more materials to increase production. A new study says a lowly fungus called white rot may offer a solution.

Currently, the bioethanol industry in the United States relies primarily on corn. However, only the grain part is used because the rest is too difficult to process. The white rot fungus, according to the study by a group of scientists from around the world, can produce unique enzymes to break down a wide range of materials, thus rendering almost the entire corn plant and other feed stocks into potential energy sources.

The white rot fungus is the only known microorganism that can break down lignin, the substance that gives plant stalks and wood their strength and rigidity. Lignin is partly the reason why many plants can’t be used to harness energy.

The study by 71 scientists from 12 countries examined the genetic sequence of the white rot species and decoded 12 of its genomes, which may change the way the biofuels industry works, said David Hibbett, lead researcher and professor of biology at Clark University in Massachusetts.

“We have, through these genomes, documented many genes that encode enzymes that are potentially useful in biofuel production,” Hibbett said. “We provide the raw materials that industrial micro biologists and people with interest can use.”

According to the study, the white rot fungus may also be what ended a coal formation period known as the Carboniferous 300 million years ago. The enzymes produced by the fungus broke down woody debris that would otherwise have been fossilized as fuel. Coal deposits that accumulated during the period have provided about 50 percent of U.S. electric power.

“They are very powerful decomposers,” said Igor Grigoriev, fungal genomics program lead at the Department of Energy’s Joint Genome Institute.

The white rot fungus is not the only microorganism that can potentially help the biofuel industry. In 2008, Montana State University researcher Gary Strobel discovered that an obscure fungus living in Patagonian rainforests actually produces a variety of the hydrocarbon components of diesel fuel by itself.

Strobel suggested that fungi living in ancient plants may have contributed to the natural formation of crude oil. He has already set up initial demonstrations based on his research.

Strobel said the results are promising. The fungi are shown to produce on a large scale energy-rich hydrocarbon at a relatively low cost.

“What I feel is this is the way of the future,” he said.