Enzymatic transesterification for biodiesel production from waste baked duck oil

The activity behavior of Novozym 435 treated with organic solvents was investigated, and the influence of several crucial parameters, including Novozym 435 dosage, oil to methanol molar ratio, reaction time and type of monohydric alcohol, on biodiesel yield was also addressed using tert-butanol as co-solvent. The results showed that the functional group as well as log P of organic solvents was an important factor affecting the activity of Novozym 435. Biodiesel yield achieved over 90% under the conditions: Novozym 435 dosage 15 wt% (based on oil weight), oil to methanol molar ratio 1:4, reaction time 20 h and tert-butanol amount 40% (based on oil volume, v/v). Novozym 435 showed a different kinetic pattern depending on the monohydric alcohols and the highest conversion rate (92%) achieved for the isopropanolysis. Novozym 435 showed high stability in tert-butanol medium, and maintained 90% of its original activity after 30 repeated cycles (600 h).