By Vikram Koundinya, graduate student, Iowa State University.

Prepared August 2008.

Introduction
Jatropha curcus, a perennial shrub, belongs to the family Euphorbiaceae. The center of origin of jatropha is uncertain, but it is believed to have originated in Mexico and Central America. It is being cultivated all over the world now. The genus Jatropha is derived from the Greek words, jatrós (doctor) and trophé (food), which alludes to its uses in medicine. It is being primarily cultivated due to its usefulness as a biofuel. It is more popular as an alternative fuel option in the developing countries compared to the United States. Though little is known in the United States, jatropha is widely viewed as a potential wonder plant in many parts of the world where longtime fuel shortages have led to development of alternative energy sources to power automobiles and factories.

Jatropha is called the wonder plant, the biodiesel tree, physic nut, Barbados nut and purging nut. It is considered a tool to combat energy poverty due to its multiple uses, most notably the production of biodiesel from oil in the seeds of its fruit. The use of jatropha in developmental programs is very popular in developing countries. Jatropha yields more oil compared to other biofuel crops and produces only 1/5 of the carbon emissions of traditional fossil fuels. Jatropha is being promoted, especially in developing countries, to make rural areas self sufficient in fuels for cooking, lighting and motive power.

Production
Jatropha is a drought-resistant perennial crop, growing well in diverse climatic conditions. It thrives well even in marginal and poor soils with less fertility levels and does not require heavy fertilization or irrigation. This plant is adapted to arid and semi-arid conditions. It thrives well at lower altitudes (0-500 m) with an average annual temperature of around 60 to 70 degrees F and rainfall of 10 to 40 inches. In low rainfall areas and during drought, it sheds its leaves as a measure of moisture conservation. It normally grows up to 4 m in length but under favorable conditions can grow even up to 8 to 10 m. It has large leaves, alternate to sub-opposite, three to five lobed with spiral phyllotaxis. Inflorescences are formed terminally on branches. The plant is monoecious and flowers are unisexual. Pollination is by insects. Plant exudes watery latex when cut. The plant can be harvested twice a year.

Jatropha grows relatively quickly and produces seeds for about 50 years. It can be established from seed, seedlings and cuttings. Plants from seeds develop a taproot and four lateral roots, while cuttings do not develop a taproot but only lateral roots. Two seeds resembling peanuts are present in the nuts. Seeds are non-edible and are toxic. The toxicity of the seeds is due to the presence of a toxic protein called curcin and diterpene esters. The toxicity symptoms include acute abdominal pain and nausea about half hour after ingestion.

Valued-Added Products
Jatropha is a multipurpose bush/small tree. The plant can be used to prevent or control soil erosion, to reclaim land, to serve as a live fence to contain farm animals and can also be planted as a commercial crop. It has few pests and diseases, and no great care is needed in the form of plant protection measures. It is not browsed by animals because its leaves and stems are toxic, but after treatment, the seeds or seed cake can be used as an animal feed. Various parts of the plant have medicinal value: the bark contains tannin, the flowers attract bees and thus the plant has honey production potential; its wood and fruit can be used for numerous purposes including fuel. The fruit of jatropha contains viscous oil that can be used in soap making and candle industry, in cosmetics industry and as a diesel/kerosene substitute or extender. When mixed with iron oxide, the oil can be also used as a varnish. The latex, oil, twigs, wood and leaves are all used externally for healing wounds, to stop bleeding and to treat rheumatism and skin diseases. As an internal medicine, the plant’s purgative, that is, vomit-inducing property can be exploited. This may be one of the substitutes for fossil fuels to counter greenhouse gas accumulation. The carbon dioxide absorption is 8 kg per tree per year and that can be converted into Carbon Credit Certificates. Jatropha products can be used as molluscicides, insecticides and fungicides. Anti-inflammatory substances and wound-healing enzymes can also be isolated from the plant.

The most important part of the plant is seeds, which yield oil that can be used as a biofuel. Jatropha contains oil of about 46 to 58 percent of kernel weight and 30 to 40 percent of seed weight. Saturated fatty acids constitute 20 percent of this, while the remaining are unsaturated ones. Oleic acid is the most abundant (44.8%) followed by linoleic acid (34%), palmitic acid (12.8%) and stearic acid (7.3%). The oil compares well against other vegetable oils and more importantly to diesel in terms of its fuel rating per kilogram or hectare of oil produced. But, the greatest difference between jatropha oil and diesel oil is viscosity. One acre of jatropha can yield between 600 to 1,000 gallons of oil per year. The trees produce up to 1,600 liters of oil per hectare per harvest. Research on this oil was first initiated during the Second World War to study its use as a liquid, renewable fuel substitute for diesel oil. Research indicates the quality of jatropha oil is better than most other crop oils for making jet fuel. Jatropha-based fuel also produces about half the harmful carbon emissions of fossil fuel. Researchers in the United States have also found that an acre of jatropha plants can yield 5 to 7 times more oil than other potential feedstocks such as soybeans. Jatropha oil is significantly cheaper than crude oil. Jatropha could be used to produce a barrel of fuel for around $43, less than the cost of sugar-cane-based ethanol ($45 per barrel) or corn-based ethanol ($83 per barrel) currently favored in the United States. There is no controversy on growing jatropha as feedstock for fuel because it is a non-food crop. Research says that farmers trying to recover from citrus canker or greening may use jatropha. Because it fares well in bad soil, the crop might be helpful for lands unsuitable for traditional agriculture. The oil has similar properties to palm oil. It can be used in place of kerosene and diesel and as a substitute for fuel wood.

Links

• Center for Jatropha Promotion, Rajasthan, India.
• D1 Oils, csr best practice, Article 13 Group, London, United Kingdom, 2005.
• Evaluation and bioinduction of energy components of Jatropha curcas, ARS, USDA, 2002.
• Jatropha Biomass: Energy for the future, Deven Leigh, Portland State University, 2007.
• Jatropha Plant Gains Steam in Global Race for Biofuels, Patrick Barta, The Wall Street Journal, 2007.
• Jatropha plant’s oil studied as biofuel for jets, Peter Pae, Los Angeles Times, 2008.
• Seed Oil of Jatropha curcas for Fuel, Food and Agricultural Organization, United Nations.