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

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 degrees C, catalyzed by a heterologous Rhizopus oryzae lipase (r-ROL) immobilized in Eupergir (R) 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, t(1/2) = 39.0 h for caprylic; t(1/2) = 54.3 h 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 (t(1/2) = 49.1 h); with rehydration, a considerable increase in stability was observed (t(1/2) = 234 h; Sadana's series-type inactivation kinetics model). (C) 2012 Elsevier B.V. All rights reserved.