White rot fungus boosts ethanol production from corn stalks, cobs and leaves

Jul 11, 2012

Scientists are reporting new evidence that a white rot fungus shows promise in the search for a way to use waste corn stalks, cobs and leaves – rather than corn itself – to produce ethanol to extend supplies of gasoline. Their study on using the fungus to break down the tough cellulose and related material in this so-called "corn stover" to free up sugars for ethanol fermentation appears in the ACS' journal Industrial & Engineering Chemistry Research.

Yebo Li and colleagues explain that supplies are facing a crunch because corn is critical for animal feed and food. They note that the need for new sources of ethanol has shifted attention to using stover, which is the most abundant agricultural residue in the U.S., estimated at 170-256 million tons per year. The challenge is to find a way to break down tough cellulose material in cobs, stalks and leaves – so that sugars inside can be fermented to ethanol. Previous studies indicated that the microbe Ceriporiopsis subvermispora, known as a white rot fungus, showed promise for breaking down the tough plant material prior to treatment with enzymes to release the sugars. To advance that knowledge, they evaluated how well the fungus broke down the different parts of corn stover and improved the sugar yield.

Treating stover with the white rot fungus for one month enabled them to extract up to 30 percent more sugar from the leaves and 50 percent more from the stalks and cobs. Because corn leaves are useful for controlling soil erosion when left in the field, harvesting only the cobs and stalks for ethanol production may make the most sense in terms of sustainable agriculture, the report suggests.

Explore further: Free the seed: OSSI nurtures growing plants without patent barriers

More information: “Enzymatic Digestibility of Corn Stover Fractions in Response to Fungal Pretreatment” Industrial & Engineering Chemistry Research. 2012, 51 (21), pp 7153–7159. DOI: 10.1021/ie300487z

Abstract
Corn stover fractions (leaves, cobs, and stalks) were studied for enzymatic digestibility after pretreatment with a white rot fungus, Ceriporiopsis subvermispora. Among the three fractions, leaves had the least recalcitrance to fungal pretreatment and the lignin degradation reached 45% after 30 days of pretreatment. The lignin degradation of stalks and cobs was similar but was significantly lower than that of leaves (p < 0.05). For all fractions, xylan and glucan degradation followed a pattern similar to lignin degradation, with leaves having a significantly higher percentage of degradation (p < 0.05). Hydrolytic enzyme activity also revealed that the fungus was more active in the degradation of carbohydrates in leaves. As a result of fungal pretreatment, the highest sugar yield, however, was obtained with corn cobs.

add to favorites email to friend print save as pdf

Related Stories

Process can cut the cost of making cellulosic biofuels

Jan 22, 2009

A patented Michigan State University process to pretreat corn-crop waste before conversion into ethanol means extra nutrients don't have to be added, cutting the cost of making biofuels from cellulose.

Research aims for more efficiency in harvest and handling

Sep 27, 2006

Kevin Shinners wants farmers to put less energy into harvesting and handling biofuel crops - less fuel, less time and less labor. As a field machinery specialist, Shinners has worked to improve the efficiency of harvesting ...

Recommended for you

User comments : 0

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.