Cold-Tolerant Jatropha Provides More Energy Options

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Jatropha curcas
Cold-tolerant strains of Jatropha curca may hold the key to tapping the Sun’s energy in areas outside the tropics.
(cc) Dinesh Valke

Ultimately, most of our energy, especially our renewable energy, comes either directly or indirectly from the sun. Thus, countries closer to the equator have more options when it comes to biofuel crops. Countries like the United States, with cooler average temperatures, have fewer choices.

Considering the obvious disadvantages associated with using food crops such as corn and soybeans for biofuel, finding alternatives is essential.

One promising possibility is Jatropha curcas, a non-edible shrub native to Central America. Its seeds contain high amounts of oil that can be used for a variety of bio-based materials including biodiesel and feedstock substitutes for the petrochemical and jet fuel industries. It can be grown on abandoned lands that are unsuitable for other crops, but its effective growing range has been limited by its lack of tolerance for freezing temperatures.

Now, SG Biofuels has identified several strains of cold tolerant Jatropha capable of thriving in climates previously thought to be outside of the crop’s preferred subtropical habitat. Utilizing the strains, the company has initiated a breeding program to develop Jatropha as an oil-producing crop in colder climates of the United States.

The strains are included among thousands of variations of Jatropha curcas the firm has collected from a range of climates and geographies around the world as part of its Genetic Resource Center, the world’s largest, most diverse collection of Jatropha genetic material.

“While Jatropha is known to thrive in warm, tropical climates, its efficacy and yield in colder regions has been considerably lower,” said Kirk Haney, President and CEO for SG Biofuels. “We believe that we have located several strains that can make Jatropha a viable oil-producing crop in a much broader range of climates here in the United States.”

The strains were collected from various sites in Central America at elevations ranging from 1,600 meters (5,200 feet) to over 1,800 meters (about 6,000 feet), where the average daily low temperature between December and February is typically around 7 degree Celsius (45 degrees Fahrenheit) and nightly temperatures can fall well below freezing.

“We typically see Jatropha thriving in climates where the average minimum temperature is about 60 degrees or more during those coldest months of the year,” said Dr. Robert Schmidt, chief scientist for SG Biofuels. “To find a collection of strains that thrive at higher elevations with considerably lower temperatures provides us with a tremendous opportunity to utilize these naturally cold adapted ecotypes to breed new varieties that will perform well in colder climates.”

With proper site selection and agronomic practices, oil yields of 750 to 1,100 liters (200-300 gallons) of extractable oil per acre are realistic today. In addition, Jatropha has very-low input costs relative to other biofuel feedstocks, which makes it profitable with current yields.

If SG Biofuel’s strains take to their new environment, they may provide the option colder climates need to reap greater benefits from the sun’s rays.

Read Biofuels and Bioenergy: Processes and Technologies from Amazon.

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