Today’srising demand for fuels has diverted the attention towards biofuels due togradual exhaustion of fossil fuels and increased pollution, causing globalwarming. Thus, an alternate source of energy is needed which is sustainable andeco-friendly. Biofuel such as bioethanol and biodiesel has already been used in addition to the fossilfueland have advantage in terms of renewability and environment friendly.
Biodiesel form plants and algae are being considered as most promising sourcesof biofuels. 1. Biodieselfrom plants, is an excellent substitute for fossil fuels as it is non-toxic,biodegradable and emits lower amount of carbon monoxides and hydrocarbons thanpetro-diesel. An important component of plant seed oils is triacylglycerols whichare highly similar to fossil fuels thus, an excellent precursor for producingbiodiesel. Transesterification of triacylglycerols in plant seed oilswith methanol in presence of an alkali or acid resulting in formation ofbiodiesel chemically known as fatty acid methyl esters (FAMEs)2. The efficiency of biodieseldepends upon the composition of fatty acids blend in the seed oil.
Five typesof fatty acids are present in plant oils which are Palmitic acid (16:0),stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and linolenic acid(18:3). Earlier, edible crop plants were used for biodiesel production whichcaused the scarcity for overall food supply and agricultural lands. Thus, forsustainable biodiesel production, non-edible crops have gained importance dueto non-competition with food security and soil with food crops. Ideal biodieselcrop can be grown in wastelands thus no competition for agricultural land for foodcrops 3. Ofmany energy plants, Jatropha (Jatrophacurcas L) has emerged as a potential bioenergy plant due to its high seedoil content (45-50%).
Jatropha is a perennial shrub or a small tree whichbelongs to family euphorbiaceae. It can grow upto a height 6 m and have 40-60 years of lifeexpectancy. Oil can be extracted from Jatropha seeds after 2-5 years dependingupon the climatic conditions. Jatropha is a monoecious plant i.e. maleand female flowers grow on the same plant. Flowers are unisexual orhermaphrodite and are pollinated by moths and bees (Raju and Ezradanam, 2002;Dehgan and Schutzman, 1994).
Morphologicallydiverse genus Jatropha comprised of more than 200 species which are dispersed primarilyin dry tropical areas of America. Jatropha, primarily originating from CentralAmerica, has been recently introduced into many tropical and subtropicalcountries in Asia and Africa. Now Jatropha is cultivated globally as abiodiesel crop (Akbar et al. 2009). Itis introduced in India in 16th century by Portuguese settlers. About18 species of Jatropha are found in India and are scattered in various statesof the country (Ginwal et al 2005). Jatropha can easily grow in extremeconditions such as in tropical savannah and monsoon climates, temperate andsemi-arid climates without any requirement of special nutritive regime (Maes etal. 2009).
Other factor for Jatropha oil popularity is the higher content ofunsaturated fatty acids and high oil content (50%) and a non-edible crop, thusno competition with food security (Table 1.1). Jatropha is listed as a fuel andfuel additive with the world environmental protection agency (WEPA) 7. Jatrophagained prominence over other oil seed plants because of its added features likeexcellent adaptability to various habitats, rapid growth, easy propagation,wide adaptability, larger fruits and seeds, drought hardiness, soilconservation capabilities, small gestation period, thriving well as live fenceand can easily be grown in wastelands.
Jatropha seeds are toxic due to the presence of phorbolesters and curcin. Even though it’s a potent biodiesel crop and toxic innature, it has a medicinal value. Most of the parts of Jatropha is used asindustrial raw material for making insecticides, soaps, cosmetics etc and asource of green manure (Gubitz et al.
, 1998; Lin et al., 2003). Though numerous efforts havebeen made to develop J. curcas as anindustrial crop, the scant information on its agronomic practices and lack ofimproved genotypes and cultivars are the major bottlenecks in its fullexploitation as a potential bioenergy crop