Biofuels: Jatropha curcas as a Novel, Non-edible Oilseed Plant for Biodiesel

Abstract

The negative environmental impacts, the limited sources and rising prices of fossil fuels pose significant environmental and socio-economic challenges. Globally, major national and international initiatives are under way to identify, revive, research and recommend renewable sources of energy. One such renewable source is esterified vegetable oil, i.e. biodiesel. Crop plants yielding edible oilseeds can be diverted to the biodiesel market only to a limited extent due to their value in the food sector. One route to meeting the gap between the demand for food oils and the need for alternative fuel oils is the use of non-edible oilseed plants such as Jatropha curcas. J. curcas or physic nut is a member of the Euphorbiaceae family and has been the subject of much interest as a source of biodiesel due to a number of perceived advantages. For example, the by-products of J. curcas-based biodiesel production have potential as a nutritious seed cake for fodder, as a soil amendment or as a biogas feedstock. Glycerol can be used in a variety of industrial applications and J. curcas leaf, stem and bark extracts have uses in the medicinal, cosmetics, plastics and insecticide/pesticide industries. As an aid to sustainable rural development, J. curcas grows on marginal and wastelands promoting effective land use, gender empowerment and soil rehabilitation. However, neither J. curcas nor any other potentially useful non-edible oilseed plant is currently grown commercially. In fact, such plants are generally undomesticated and have yet to be subject to any genetic improvement with respect to yield quality or quantity. Also, many J. curcas accessions can be toxic to humans and animals due to the presence of toxic compounds such as curcins and phorbol esters. Thus, despite the enthusiasm in some countries for widespread plantation cropping, J. curcas is currently not commercially viable as a biodiesel feedstock without genetic improvement either through conventional breeding or molecular engineering because of unpredictable yield patterns, varying, but often low, oil content, the presence of toxic and carcinogenic compounds, high male to female flower ratio, asynchronous and multiple flowering flushes, low seed germination frequency, plant height and its susceptibility to biotic and abiotic stresses. This paper reviews the potential of Jatropha as a model, non-edible, oilseed plant and the research needed to realize its potential as a bioenergy crop.

Genetic diversity of Jatropha curcas L. populations in Kenya using RAPD molecular markers: Implication to plantation establishment

“…The Jatropha plant is a new system and only recently exposed to molecular investigations, mainly due to its increasing popularity as a biodiesel feedstock and valuable co-products (Kohli et al, 2009). This study constitutes the first successful attempt to assess genetic diversity of J. curcas using molecular markers in Kenyan provenances when compared with India, where a lot of studies have been done.…”

Biofuels in the Quest for Sustainable Energy Development

“…Bioenergy (biofuel) is considered as a potential source of energy due to its numerous and overwhelming environmental, socioeconomic benefits including rural development, land and soil reclamation (Farrell et al, 2006;Hill et al, 2006;Schubert, 2006;Vertès et al, 2006;Agarwal, 2007;Demirbas, 2007;Righelato and Spracklen, 2007). Developing countries such as China, India, and Brazil are considered as the major sources and markets for renewable energy due to the need to meet their energy demand owing to rapid industrialization and high population increase (Kohli et al, 2009). Huge amount of energy is consumed as electricity, power, heat and fuels in residential, commercial, industrial and transport sectors.…”

“…will be depleted earlier than the predicted as a result of increase in world population to 8 billion by 2025 (Agarwal, 2007;Worldwide Institute, 2007;Kohli et al, 2009). The emission of green house gases (CO 2 and CH 4 ) by gasoline and diesel automobiles is a major source of environmental contamination; the combustion of fossil fuels contributes significantly to global warming and acid rain.…”

“…The emission of green house gases (CO 2 and CH 4 ) by gasoline and diesel automobiles is a major source of environmental contamination; the combustion of fossil fuels contributes significantly to global warming and acid rain. The global temperature is expected to rise by 6.4ºC by the end of the 21 st century; this increase is attributed to high increase in green house gases with consequent effects on the fauna and flora (Agarwal, 2007;Kohli et al, 2009). The price of crude oil, natural gas and coal is affected by lots of factors making it unstable and unpredictable.…”

“…The high price of crude oil affects economic growth and efficient use of energy. This is coupled by tight regulations on emissions of wastes from fossil fuels and other sources of non-renewable energy in Europe and USA (Agarwal, 2007;Kajikawa and Takeda, 2008;Kohli et al, 2009). …”