Batch operational stability of immobilized heterologous Rhizopus oryzae lipase during acidolysis of virgin olive oil with medium-chain fatty acids

► Rhizopus oryzae heterologous lipase (r-ROL) was immobilized in different supports. ► r-ROL was able to catalyze acidolysis of olive oil with caprylic or capric acid. ► r-ROL was reused, either without or with biocatalyst rehydration between batches. ► Operational stability of r-ROL in Lewatit VPOC 1600 increased with rehydration. Structured triacylglycerols containing medium-chain fatty acids (M) at positions sn-1,3 and long-chain fatty acids (L) at the sn-2 position (MLM type), were obtained by acidolysis of virgin olive oil with caprylic or capric acid, in solvent-free media, at 40°C, catalyzed by a heterologous Rhizopus oryzae lipase (r-ROL) immobilized in Eupergit® C or in Lewatit VP OC 1600. The biocatalyst immobilized in Eupergit® was reused in consecutive 23-h batches with rehydration of the biocatalyst between batches. A first-order deactivation was observed (half-life time, t1/2=39.0h for caprylic; t1/2=54.3h for capric acid). During acidolysis with capric acid catalyzed by r-ROL immobilized in Lewatit VP OC 1600, without rehydration, a first-order deactivation was observed (t1/2=49.1h); with rehydration, a considerable increase in stability was observed (t1/2=234h; Sadana's series-type inactivation kinetics model).