October 22, 2007
Earless corn shows potentials for US ethanol
A scientist from University of Illinois scientist has discovered "new tricks" from an old plant that could change the ethanol industry in the US.
Fred Below, professor of plant physiology, began growing tropical corn near the university at Urbana-Champaign more than two decades ago to study the genes involved in the plant's use of nitrogen. But it wasn't until recently that the plant became appealing for a different reason.
In his observation, tropical corn is a "short-day plant" which can grow tall and lush in temperate conditions. But this biological nuance will be of value with all the interest in biofuel crops, says Below.
The value is that the plant stores simple sugars in its stalk rather than growing ears. This sugar is easier to process into ethanol than traditional corn.
Corn ethanol production methods require breaking down cornstarch into simple sugars, which are then fermented into ethanol. Since tropical corn already stores its energy in the form of simple sugar, this intermediary step is unnecessary.
The result is a plant similar to sugarcane, which also stores sugars in its stalk and is a source of cheap ethanol.
In terms of energy required to produce it, sugarcane ethanol is also more efficient than either gasoline or corn ethanol.
According to studies performed by Michael Wang at Argonne National Laboratory, one unit of energy output from gasoline requires 1.2 units of energy input when all aspects of gasoline production are taken into account.
One unit of energy output from corn ethanol, on the other hand, only requires .74 units of energy input. Sugarcane ethanol is about four times as efficient as corn ethanol.
Unfortunately, sugarcane can't be grown in the Midwest climate, and steep tariffs effectively bar Brazilian sugarcane ethanol from entry into the US market. Tropical corn, however, could provide a viable alternative to sugarcane for cheap and efficient ethanol.
The plant has other benefits over traditional corn as well.
Corn requires a tremendous amount of nitrogen fertilizer, which runs off into streams and other water sources and wreaks havoc on the environment. Tropical corn, since it doesn't produce ears, requires less fertilizer.
Below said fertilizing corn is about making grain and will need a lot less of nitrogen.
What Below found, in fact, was that applying nitrogen fertilizer to tropical corn reduced the plant's sugar production.
Tropical corn is also attractive because it could be harvested with the same equipment already in use to harvest traditional corn, unlike other potential sources of biofuel. The plant can also be easily rotated with traditional corn or soy. If a farmer doesn't like it, he can plant a different crop next year, he said.
Hans Blaschek, director of the Centre for Advanced BioEnergy Research at the University of Illinois, is looking into the potential commercial aspects of tropical corn ethanol.
Sugar extraction from tropical corn is such a new process that more testing is needed to determine whether it can support the organisms necessary for ethanol production, Blaschek said.
But since announcing the implications of tropical corn on the university web site a few days ago, Blaschek says it has elicited a "large amount of interest" from the ethanol industry.
Les Nelson, a spokesman at Aventine Renewable Energy Holdings Inc., said he wasn't familiar with tropical corn.
Blaschek will be part of a team that travels to Brazil in November to study methods of ethanol production from sugarcane in the country. The trip may yield insights that could be used in the production of ethanol from tropical corn.
According to Blaschek, existing corn ethanol factories would require little transformation to produce tropical corn ethanol.
Below is fine-tuning the plant's genetics to increase its sugar production even further.
Blaschek said "tropical corn is the next best thing since sliced bread" and the positive results are just a tip of the iceberg."
