Batch and continuous production of biolubricant from fusel oil and oleic acid: Lipase screening, reactor system development, and reaction optimization

Abstract Fusel oil was used as a source of isoamyl alcohol in the synthesis of biolubricant by esterification with oleic acid catalyzed by different sources of lipase immobilized on poly(styrene/divinylbenzene) copolymer resin. In preliminary tests, Rhizopus oryzae lipase showed satisfactory performance, providing high molar conversion of the starting materials (>90% in 24 h of reaction), and was selected for subsequent experiments. The optimal conditions for isoamyl oleate production by immobilized R. oryzae lipase were 1:1.5 ratio of fusel oil to oleic acid and reaction temperature of 45°C. Continuous runs were carried out in a two-stage packed-bed reactor coupled to a water extraction column filled with molecular sieves. Each reactor stage was loaded with 2.6 g of immobilized lipase and then fed with fusel oil and oleic acid at a 1:1.5 molar ratio in the presence of isooctane. The performance of the proposed system was tested at a space time of 10.2 h, resulting in a mean ester productivity of 292.20 ± 18.46 µmol g−1 min−1 and biocatalyst half-life of 179.6 h. The properties of purified samples were in accordance with standard requirements for biolubricants.