Production of low-calorie structured lipids from spent coffee grounds or olive pomace crude oils catalyzed by immobilized lipase in magnetic nanoparticles

[Display omitted] •Valorization of spent coffee grounds (SCG) and olive pomace (OP) crude oils.•Rhizopus oryzae lipase immobilization in magnetic nanoparticles (MNP-ROL).•MNP-ROL more efficient than Thermomyces lanuginosus lipase (Lipozyme TL IM).•High stability of MNP-ROL in acidolysis and interesterification of OP oil. In this study, crude oils extracted from spent coffee grounds (SCG) and olive pomace (OP) were used as raw-material to synthesize low-calorie triacylglycerols, either by acidolysis with capric acid, or by interesterification with ethyl caprate, in solvent-free media, catalyzed by sn-1,3 regioselective lipases. The Rhizopus oryzae lipase (ROL) was immobilized in magnetite nanoparticles (MNP–ROL) and tested as novel biocatalyst. MNP-ROL performance was compared with that of the commercial immobilized Thermomyces lanuginosus lipase (Lipozyme TL IM). For both oils, Lipozyme TL IM preferred interesterification over acidolysis. MNP-ROL catalyzed reactions were faster and acidolysis was preferred with yields of c.a. 50% new triacylglycerols after 3 h acidolysis of OP or SCG oils. MNP-ROL was very stable following the Sadana deactivation model with half-lives of 163 h and 220 h when reused in batch acidolysis and interesterification of OP oil, respectively.