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® Transform 2.0 (ET2) (12 US$/kg) in solvent-free system. The maximum biodiesel yield of 98.63 % was obtained under the optimized conditions of 32 °C, 8.5 wt.% lipase dosage, 8 h, 6.5/1 methanol/oil molar ratio, and 4 wt.% water. Lipase ET2 was recycled 6 times at > 89.52 % biodiesel yield. Biodiesel yield of 93.94 % was further achieved in a 1 L reactor with 15.08 g/kg lipase/biodiesel. Biodiesel cost was estimated as 589.3 US$/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.