Biodiesel production via simultaneous esterification and transesterification of Periplaneta americana oil with liquid lipase Eversa® transform 2.0

Undeveloped Periplaneta americana oil (acid value 38.32 mg KOH/g) was directly used for one-step production of biodiesel with lipase without acid-pretreatment step for the commercial alkaline process. Biodiesel was produced via simultaneous esterification and transesterification of Periplaneta americana oil in the presence of lipase Eversa (R) Transform 2.0 (ET2) (12 US$/kg) in solvent-free system. The maximum biodiesel yield of 98.63 % was obtained under the optimized conditions of 32 degrees C, 8.5 wt.% lipase dosage, 8 h, 6.5/1 methanol/oil molar ratio, and 4 wt.% water. Lipase ET2 was recycled 6 times at > 89.52 % biodiesel yield. Biodiesel yield of 93.94 % was further achieved in a 1 L reactor with 15.08 g/kg lipase/biodiesel. Biodiesel cost was estimated as 589.3 US$/ton. Kinetics study gave activation energy of 24.50 kJ/mol with kinetic Michaelis constant of 1.19 mol/L. The physicochemical properties of biodiesel met both Chinese national and US ASTM standards that could be blended with petro-diesel to be applied in both countries. This study suggests that lipase could directly catalyze waste oils for the production of biodiesel at low temperature.