Agave might be ‘missing energy crop'

By Lisa Gibson
Posted October 19, 2009, at 11:08 a.m. CST

Agave, a plant of a large botanical genus grown mainly in Mexico, is the missing energy crop, according to researchers participating in the Agave Project, and could be revolutionary for the biofuels and bioproducts industries.

The plant is used to produce liquors such as tequila, mescal and sotol, along with cords and ropes mainly for handcrafts. But its potential has largely been untapped, according to researchers. One hectare (2.5 acres) of the plant annually produces more than 500 metric tons (551 tons) of biomass, yielding three times more sugars than sugarcane, four times more cellulose than the fastest-growing eucalyptus, and five times more dry biomass than the genetically modified poplar tree, according to researcher Arturo Velez Jimenez. "It's a reliable, abundant, cheap, easy to handle, high-quality feedstock," he said. "It's the ideal feedstock for a biorefinery where electricity, biofuels, biomaterial, chemicals and bioproducts are produced." One hectare can produce 5,000 gallons of distilled ethanol and 5,000 gallons of cellulosic ethanol, he said.

Agave is not currently used to make biofuels, but is capable of producing any type, Jimenez said. It thrives on marginal lands, including in salty and acidic soils, on steep hills and in semiarid and temperate climates; needs neither watering nor agrochemicals; and can be easily cultivated at a very low cost, Jimenez said. In Mexico alone, there are more than 80 million hectares (198 million acres) of marginal and semiarid land where agave plantations could be established, he said.

It does not compete with food crops either. "When I was a kid, men walked the streets selling toasted agave, a candy with a very soft taste of alcohol," Jimenez said. "Nowadays, nobody makes this anymore. It's not used to make food anymore." Sometimes during drought the leaves are fed to cattle, he added, and the skin is used to wrap and cook mixiote, a traditional popular dish with meat, herbs and sauce.

The Agave Project was started four years ago when Jimenez was the national administrative coordinator at the National Confederation of Forestry Producers, he said, to explore and promote the potential of the plant. Now, he's developing the project separately from the agency. It uses the research of University of Chicago Professor Remigio Madrigal Lugo, who developed enhanced varieties of Agave tequilana weber, Agave angustifolia and Agave fourcroides, according to Jimenez. Those enhanced varieties have a higher sugar content and are several times bigger than common agave. The enhanced tequila variety, for example, produces six to 10 times more tequila than common agave, Jimenez sites.

There is enough of the crop to sustainably supply a biofuels industry, while continuing to produce tequila, he said. "There's enough agave in Mexico for massive production of ethanol, biofuels and bioproducts," he said. "Right now, there's an overpopulation of agave. More than 225 million mature agave plants won't be commercialized because the tequila industry cannot buy them."

Jimenez is developing the Agave Project in South Africa and seven adjacent countries, he said. He strives to get several different companies and technologies producing different biofuels to test the plant. Mascoma is assessing Agave americana for its cellulosic ethanol conversion process, Jimenez said, and he's in discussions with companies to convert the plant to biocoal and biochar, biojet fuel and biocrude.