Base catalysts like NaOH and KOH are effective when FFA levels are below 3%. If higher, an initial acid-catalyzed esterification using sulfuric acid (H₂SO₄) reduces FFAs before a base reaction. This two-step process prevents soap formation and maximizes yield. Supercritical methanol and enzyme-based methods also work but are costlier. The GlobeCore USB system is flexible—capable of handling both base and acid-catalyzed reactions—ensuring high conversion efficiency regardless of FFA content in Jatropha oil.