Biodiesel can be made from any oil/lipid source; the major components of these sources are triacylglycerol molecules. In general, biodiesel feedstocks can be cate­gorized into three groups: pure vegetable oils, animal fats, and waste cooking oils.

Biodiesel from Pure Vegetable Oil

The first group is pure oils derived from various crops and plants such as soybean, canola (rapeseed), corn, cottonseed, flax, sunflower, peanut, and palm. These are the most widely used feedstocks by commer­cial biodiesel producers. The oil composition from vege­table crops is pure; this cuts down on preprocessing steps and makes for a more consistent quality of bio­diesel product. However, there is an obvious disadvan­tage for vegetable oils as biodiesel feedstocks: wide scale production of crops for biodiesel feedstocks can cause an increase in worldwide food and commodity prices. Such a "food vs fuels" debate has reached national atten­tion when using vegetable oils for biodiesel production. Alternative feedstocks usually arise out of necessity from regions of the world where the above materials are not locally available or as part of a concerted attempt to reduce reliance on imported petroleum.

JATROPHA CURCAS (JATROPHA)

The nonedible oil from Jatropha curcas (Jatropha) has recently attracted extensive attention as a feedstock for biodiesel production in India and other climatically par­allel regions of the world (Kumartiwari et al., 2007; Kalbande et al., 2008). The Jatropha tree is a perennial shrub belonging to the Euphorbiaceae family whose seeds contain up to 30 wt% oil. This plant can be found in tropical and subtropical regions such as Africa, Indian subcontinent, Central America, and other countries of Asia. Since Jatropha oil contains a relatively elevated percentage of saturated fatty acids (Table 1.4), the corre­sponding methyl esters display relatively poor low

temperature operability, as evidenced by pour point (PP) value of 2 °C (Kumartiwari et al., 2007).