A new generation of ecocatalysts derived from Invasive Alien Species (IAS) (Fallopia japonica and Arundo donax) was used as starting material for the preparation of novel biosourced catalysts. The preparation of these ecocatalysts is a new way to support the management of IAS. These catalysts were characterized by microwave plasma atomic emission spectrometry (MP-AES) and X-ray powder diffraction (XRPD), which revealed basic properties. After calculating Pearson’s correlations to evaluate the relative importance of reaction parameters, a design of experiments (DoE) was implemented to synthesize glyceryl caprylate and oleate with a high selectivity. These molecules constitute emollients and non-ionic emulsifiers of high industrial interest. The ecocatalysts were efficient and recyclable for the transesterification of methyl and ethyl fatty esters, leading to high yields (66–83%). These ecocatalysts are an alternative to usual base catalysts previously reported for the transesterification of methyl caprylate, methyl oleate and ethyl caprylate with glycerol, which are often non-recyclable, not systematically selective and require questionable preparation conditions.