Thu, 10/08/2015 - 10:03am
Greg Watry, Digital Reporter
Image: T photography/Shutterstock.com
Famous for its role in tequila and mezcal production, the agave plant was worshipped by Mexico’s natives long before the Spaniards arrived in the 15th century. The Aztec goddess Mayheul was closely associated with agave, a symbol for life, health, dance and fertility. According to the International Organic Agave Alliance, archeological findings date the plants usage back some 10,000 years.
But the broad-leafed, spiky plant may have more use than just supplying a bottle of spirits for a wild weekend revelry.
Researchers from the Australian Research Council Centre of Excellence in Plant Cell Walls released a study in PLOS ONE touting the plant as a potential source for biofuel.
“Bioethanol yields from agave fermentation could rival the most successful biofuel feedstock crops around the world,” said co-author Prof. Rachel Burton, of the Univ. of Adelaide’s School of Agriculture, Food and Wine. “Importantly, it doesn’t compete with food crops; it’s fast growing so the whole plant could be used rather than just harvesting the leaves; and it is up to 10 times more water efficient than some other crop plants.”
Studying Agave americana and Agave tequilana, the researchers found use of the former could yield 4,000 to 13,600 L/ha/yr, and the latter, 4,400 to 14,800 L/ha/yr. If the whole plant is used, that is. Even at the low end, the values surpass theoretical yields from first-generation feedstocks, such as corn, wheat and sugarcane, according to the researchers. The high values double yields from recently investigated biofuel sources, such as poplar, sorghum and switchgrass.
Tequila and mezcal are made from the stem tissue of Agave tequilana when the plants are between eight and 12 years old. When heated, the stem tissues release fermentable fructose. However, the leftover leaves, which the researchers say accounts for 66% of the biomass, is discarded.
“Waste leaves could generate up to (8,000 L/ha/yr) and increase profit from the agave crop, or, if directly separating and fermenting the juice was more economically viable, up to 4,000 (L/ha/yr) is achievable,” said Burton.
Research is in progress to find the best cultivation methods for bioethanol production.