December 28, 2011

Pinhao Manso Promoted as Alternative to Soy Oil for Biodiesel

In their search for alternative vegetable oils used to produce biodiesel, Brazilian scientists feel they have identified a good candidate to replace soybean oil which currently comprises 80% of the vegetable oil used to make biodiesel. One of those potential alternatives is a plant called pinhao manso in Portuguese (Jatropha curcas) or some of the common English names for the plant are Barbados Nut, Purging Nut, or just its initials of JCL which stands for Jatropha curcus Linnaeus.

The plant is a semi-evergreen shrub or small tree that is native to the tropics of Central and South America. The nuts contain 27% to 40% oil by weight and the oil is very high quality and generally used to produce biodiesel fuel. Researchers from the Agronomic Institute of Campinas (IAC) in the state of Sao Paulo plan on releasing a new variety of pinhao manso by 2015 that would be suited for large scale production throughout Brazil.

The varieties available today have not been breed for domestic production, but that is about to change. The scientists want to modify the plant in a number of ways including its height. The natural height of the plant is 5-6 meters, but breeders plan on producing a variety that is no more than a meter and a half high to facilitate mechanical harvesting.

Another characteristic they want to introduce is for all the fruits to become mature at the same time, also to facilitate mechanical harvesting. Currently the plant and nuts are poisonous, but researchers feel they will be able to eliminate the toxins from the plant so that the residue left over after the oil has been extracted can then be used for animal feed. They also will be looking to incorporate pest and disease resistance into the new variety.

Researchers are taking two different approaches to achieve their goal. One approach is to use some of the inherited variability found in existing varieties of the plant to develop the new variety with more desirable traits. The other approach is to identify if the desirable characteristics such as tolerance to cold temperatures or water shortages already exist in wild species of the plant and then breed those characteristics into the new variety.

In the warmer tropical areas of Central and South America, the plant flowers and bears fruit twice a year, but in southern Brazil, it only flowers once a year. Yields of the nonedible nuts are currently in the range of 8,000 kg/ha, but that will surely increase with additional research. Researchers feel the plant could be cultivated by small, medium, or large producers, but large-scale production would be needed to justify the construction of a biodiesel plant. Techniques used to produce castor bean could also be used to produce pinhao manso.

The nuts can be stored for long periods of time without any deterioration of the oil and since the oil is nonedible, it would avoid the question of food vs. fuel that is constantly being raised with corn-based ethanol and soybean oil-based biodiesel. The food vs. fuel debate may also keep other potential alternatives such as palm oil, peanut oil, and cotton seed oil from ever reaching large scale production. pinhao manso would be solely grown for biodiesel production.