Biology and biotechnological advances in Jatropha curcas - A biodiesel plant

Abstract

Increasing global demand for energy, the impending depletion of fossil fuels, and concern over global climate change have lead to a resurgence in the development of alternative energy sources. Bio-fuels and bio-energy encompass a wide range of alternative sources of energy of biological origin, and offer excellent, environmentally friendly opportunities to address these issues. The recognition that Jatropha oil can yield high quality biodiesel has led to a surge of interest in Jatropha across the globe, more so in view of the potential for avoiding the dilemma of food vs fuel. Hardiness, rapid growth, easy propagation, short gestation period, wide adaptation, and optimum plant size combine to make this species suitable for sustainable cultivation on wastelands. Besides biodiesel from the seed, the plant produces several useful products that also have commercial value. Large scale cultivation remains the single most important factor that will ultimately determine the success of Jatropha as a source of bio-fuel. The limited knowledge of the genetics of this species, low and inconsistent yields, the narrow genetic variability, and vulnerability to insects and diseases are major constraints in successful cultivation of Jatropha as a bio-fuel crop. Despite the optimal protein content and composition of the pressed cake, the presence of phorbol esters makes it unsuitable for consumption by livestock. A non-toxic variety with low or no phorbol ester content has been identified from Mexico, and the utility of pressed cake from this variety as livestock feed has been demonstrated successfully. In the absence of any morphological differences, identification of linked markers for toxic/non-toxic varieties will add value to the crop and facilitate further improvement. This chapter discusses current efforts towards assessing the diversity and phylogeny of Jatropha, identification of specific markers for toxic and non-toxic varieties, and aspects of micropropagation and genetic transformation.