Avant-Garde Agave

A group of researchers are touting agave, a plant traditionally used to produce tequila, as a revolutionary cellulosic ethanol feedstock.
By Anna Austin
As the pursuit for the perfect cellulosic ethanol feedstock continues, new light is being shed on plants traditionally used for different purposes. A group of Mexican researchers believe they've discovered what they call the "missing energy crop," and though it hasn't exactly been missing-it grows abundantly in Mexico and in some southern U.S. and South American locations-these scientists claim agave possesses characteristics superior to other feedstocks currently being examined for biofuel purposes, such as cellulosic ethanol production.

Researcher Arturo Velez Jimenez is a developer of the Agave Project, designed to explore and promote the potential of the plant, which began four years ago when he was the national administrative coordinator at the National Confederation of Forestry Producers in Mexico. Now developing the project separately from the agency, Jimenez says the research currently extends into all 17 agave regions of Jalisco State (central-western Mexico) and will soon become a nationwide project. Local Congressman Jose Luis Ortega, Juan Frias of Bioenergy Solutions, Professor Juan Villalvazo at the University of Guadalajara, the Mexican Agavaceas Net and the State Council of Agave Tequilana Producers are also participating in the project, he adds.

The core of the project is based on the research of Remigio Madrigal Lugo, a professor at the University of Chicago, who developed enhanced varieties of agave tequilana weber, agave angustifolia and agave fourcroides, according to Jimenez.

Now convinced that agave is the missing energy crop, he tells Biomass Magazine that the high-quality feedstock is reliable, abundant, easy to handle, and possesses an interesting history.

Crop History

Agave is arguably one of the most significant plants in Mexican culture. It has a rosette of thick fleshy leaves, each of which usually end in a sharp point with a spiny margin, and is commonly mistaken for cacti.

According to Jimenez, more than 100 uses for the crop have been documented. "It was used as a food 9,000 years ago and probably was the main source of carbohydrates in ancient Mexico, before corn," he says. "When I was a kid, men walked the streets selling toasted agave, a candy with a very soft taste of alcohol. Nowadays, nobody makes this candy and agave isn't used as a food. Sometimes during drought, the leaves are fed to cattle, and some people collect agave worms, which are toasted and used in mescal bottles."

There were three agave industries in the beginning of the 20th century-tequila, pulque (a milk-colored alcoholic beverage) and henequen (ropes and cords)-in pre-capitalist Mexico, Jimenez explains. "Huge fortunes were accumulated. But then the revolution came and those industries were abandoned by the new powers-to-be, except for tequila, which some people kept producing in spite of it being forbidden. Then, tequila developed a culture of its own."

The tequila industry became popular and rather than becoming concentrated in a few hands, profits were widely distributed; a large part of the population had money to spend. "Clothing, music, dances, food and even the mariachi (traditional Mexican music) emerged from the tequila industry," Jimenez says. "Mexico is known internationally, thanks to the tequila culture."

With the many uses for agave, one might question whether there's enough of the crop for fuel purposes, but Jimenez says there's enough agave in Mexico alone for massive production of ethanol and other biofuels. In fact, overproduction has become a problem and about 225 million mature agave plants won't be used because the tequila industry cannot buy them.

There is a reason for the surplus, Jimenez points out. About 10 years ago, a plague killed millions of plants. "There wasn't enough agave tequiliana to produce tequila," he says. "Prices went up 20 pesos per kilo of agave so many people planted it, and now there's overproduction. This year, one kilo of agave head was worth one-hundredth of its cost 10 years ago, and producers are suffering. It's a paradox-they have a gold mine in their fields, only they don't know it."

Jimenez is trying to convince the Mexican government to start a biofuel industry based on agave. "The tequila industry is very powerful, though," he says. "They don't want anything to bother them. Tens of thousands of families could lose their crops."
In the meantime, the Agave Project will continue to build on research dating back several decades.

Research and Yields

Lugo has been working to develop enhanced strains of different varieties of agave, including agave tequilana, angustiflio and fourcrocides, which Jimenez says have even higher sugar content and the plants are several times larger than typical agave strains. "His agave tequilana variety, for instance, produces six to 10 times more tequila than common agave," he says.

Lugo's initial agave research began in 1979, when the first agave plantation was established in Yucatan, Mexico, using an in vitro propagation protocol. In the following years, work continued with different strains of agave being developed with respective protocols for propagation in vitro. Since then, all propagation has had to be done from immature plants, since mature plants didn't allow this type of propagation, Jimenez adds. "But immature plants don't have well-defined characteristics. Thus the seedlings could be large and productive or small and unproductive, resulting in very diverse plantation. The possibility to propagate mature plants, with well-defined characteristics allows the industry to select only the best plants to propagate."

In agave characterization, among other qualities of production importance is the weight of the plant head, which determines sugar content-the heavier the head the higher the sugar content, according to the research. Lugo and Jimenez say some agave strains can possess three times more sugar than sugarcane in Brazil, four times more cellulose than the fastest-growing eucalyptus, and five times the amount of dry biomass than the genetically modified poplar tree; one hectare (2.47 acres) of agave usually produces more than 500 metric tons (551 tons) of biomass.

Fields of Dreams

The question is, what will it take to jump-start the agave-to-ethanol industry in Mexico? According to a report generated from a research project undertaken at Chapingo Autonomous University, agave ethanol production in Mexico would require a subsidy of 29 cents per liter for agave refineries to support a sustainable renewable energy economy, which is described by researcher Antony Maldonado Sanchez as being a feasible policy since the U.S. government subsidizes ethanol obtained from corn at approximately 28 cents per liter.

As for the reach of the Agave Project, Jimenez says the group plans to get the Chamber of Tequila Industry or several major tequila industries, as well as state and municipal government dependencies, the National University and other research centers and international biofuels wholesalers involved in the project.

The group is working to secure additional funding, a task Jimenez is confident will be completed soon. "We plan to ask for help from the Global Sustainable Biomass Fund for a subsidy to promote the Agave Project," he said. "There are several groups of interested international investors, as well as the CO2 Foundation of The Emirates Airline (Foundation), and a Canadian bank."

Several different industries are also interested in agave. "Its low cost, high yields, superb quality of sugars, all-year round harvesting and its high cellulose content-up to 68 percent-are very attractive," Jimenez says. We will be sending agave biomass samples for testing to the best commercial technologies available in the production of all kinds of biofuels. We have a first-prize-winner energy crop and we want to mate with companies with first-prize-winner technologies."

He adds that they are already quietly working with some companies. For example, Massachusetts-based Mascoma Corp. has been evaluating cellulosic ethanol production utilizing agave bagasse. Jimenez said the Mexican Ministries of Economy and Agriculture are interested in having Mascoma visit Mexico for that purpose and are providing their assistance.

Beyond Mascoma, the Energy Biosciences Institute at the University of Illinois is evaluating agave, and Jimenez is also working with Washington-based Clearsky Energy Systems Inc., which is exploring the possibility of building municipal electricity-generating facilities that run on syngas produced from the gasification of agave biomass.

Future plans for the Agave Project include delving into the production of biochar, biocoal and possibly biocrude or biojet fuel from the crop, and growing agave for renewable energy purposes all across Mexico. "Just in Mexico, there are more than 80 million hectares of marginal and semiarid land where agave plantations could be established, and massive production of agave biochar and biocoal could have a real impact on climate change," Jimenez says. "It could also become a very prosperous business in the U.S., China and many other countries. I think agave is here to stay. As more and more people discover it, it will become very popular and be a gift from Mexico to the world." BIO

Anna Austin is a Biomass Magazine associate editor. Reach her at aaustin@bbiinternational.com or (701) 738-4968.