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Optimized Production of MLM Triacylglycerols Catalyzed by Immobilized Heterologous Rhizopus oryzae Lipase
- Nunes, P. A., Pires-Cabral, P., Guillén, M., Valero, F., Ferreira-Dias, S.
- journal of the American Oil Chemists' Society 2012 v.89 no.7 pp. 1287-1295
- fatty acids, fermentation, Komagataella pastoris, yeasts, models, triacylglycerols, triacylglycerol lipase, response surface methodology, Rhizopus oryzae, virgin olive oil, temperature, acidolysis
- Response surface methodology was used to model and optimize the acidolysis of virgin olive oil with caprylic (C8:0) or capric (C10:0) acids, aimed at the production of low caloric triacylglycerols (TAG) of MLM type, in solvent free media, catalyzed by the heterologous Rhizopus oryzae lipase (r-ROL) immobilized in Eupergit® C. This lipase was produced in the methylotrophic yeast Pichia pastoris Muts phenotype (experiments with C10:0) or a Mut+ phenotype (experiments with C8:0), under different operational conditions. The r-ROL used in experiments with C10:0 presented a hydrolytic activity about 5 times of that presented by r-ROL used in acidolysis with C8:0. The experiments were carried out following a central composite rotatable design, as a function of the molar ratio (MR) medium chain fatty acid/TAG (1.6–4.4) and temperature (25–55 °C). Convex surfaces described by second order polynomials as a function of MR and temperature were well fitted to fatty acid incorporation values. After 24-h reaction, the predicted maximum incorporation of caprylic (15.5 mol%) or capric (33.3 mol%) acids in olive oil occurs at 37 and 35 °C, respectively, and at C8:0/TAG of 2.8:1 or C10:0/TAG of 3:1. These predicted optima were experimentally validated. Fermentation conditions used in r-ROL production highly affected hydrolytic activity and to a lesser extent interesterification activity.