Melo (2006) produced biodiesel from the direct transesterification of jatropha oil with acidity of 3.13 mg KOH g−1, what leads to the conclusion that the reduction of acidity caused by treatment 6 enables similar results to those of this author, once that the acidity obtained in this study was 3.12 mg KOH g−1 without the need for neutralization to achieve such result, making the use of jatropha for biodiesel production feasible.