*2.3. Ethanolisis Reactions*

The transesterification reactions of sunflower oil were carried out according to the experimental procedure previously described [26]. Briefly, a 25 mL volume round bottom flask was immersed in a thermostatic bath in which temperature and stirring speed were controlled. The temperature was set to 35 ◦C whereas the stirring speed was set at 700 rpm to avoid mass transfer limitations. In a typical run, 9.4 g (12 mL, 0.01 mol) of sunflower oil was introduce in the batch reactor together with variable oil/ethanol volume ratio, corresponding to a molar ratio between 1/4 and 1/6, different amounts of supported Lipozyme RM and also different amounts of NaOH 10N (0–75 μL). Blank experiments in presence of the highest quantity of NaOH 10N solution were performed to rule out a potential contribution from the homogeneous NaOH catalyzed reaction. In these blank experiments, less than 10% of conversion was obtained, indicating that the homogenous catalysis contribution is negligible under the investigated conditions. At the end of the reaction, the biocatalyst was employed without any treatment, in order to simulate the operational conditions employed in the industry. Thus, by simple decanting for half an hour, the biocatalyst is maintained at the bottom of the flask and the product is retired. Then, a new charge of reactants is added and the reaction is launched again.
