**2. Obtaining biodiesel on a laboratory scale**

### **2.1 Sample collection**

As discussed earlier, biodiesel can be obtained from low value-added fat feedstocks, i.e., with high free fatty acid (FFA) content. Such feedstocks are pretreated to suit the alkaline methanol transesterification process.

Initially, in native forest in the municipality of Zé Doca (Maranhão, Brazil), tucum (Bactris setosa) coconuts were collected, containing a small hole in its endocarp, indicative of containing the gong (Pachymerus nucleorum) inside these materials. The endocarp of the selected coconuts was broken and the gongs were removed from its interior.
