The content of final moisture in the sludge is an important factor that explains the adverse effect on the lipid extracted as well as biodiesel produced. Water contained within the biomass has a tendency to shield lipids from the extracting solvent. As seen in Table 2, the final moisture content in the sludge depends on the temperature of the drying method. At high temperature (70 °C, 105 °C), the content of moisture is low, but always higher than that of the MgSO4·H2O method. Furthermore, it was observed for experiments with oven at 70 °C, freeze-dried, fume hood, and sun drying that the solid particles were more compact, even after grinding. The water content could surround the sludge particles and thus inhibit the good penetration of hexane inside the solid particle. As Table 2 shows, in general, the greater the amount