607 Jatropha Seed Oil (Fuel) The seed oil is not edible as it contains toxic compounds. Traditionally, it is used for the manufacture of candles and soap, as lamp oil and as fuel for cooking. Jatropha curcas is increasingly planted for bio-fuel purposes. The oil is either used directly in adapted engines powering local grain mills, oil presses, water pumps and small generators, or first refined by trans-esterification with methanol or ethanol to produce regular fuel suitable for high-performance diesel engines. 8,017