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

•Immobilized Rhizopus oryzae lipase was the most efficient catalyst in ester synthesis.•Continuous operations obtained high productivity and stability of the biocatalyst.•Fusel oil can be used as a source of low cost isoamyl alcohol to produce isoamyl oleate.•The ester obtained was very similar to that commercially available. 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. [Display omitted]