Release of Omega-3 Fatty Acids by the Hydrolysis of Fish Oil Catalyzed by Lipases Immobilized on Hydrophobic Supports

The release of omega-3 fatty acids by the mild enzymatic hydrolysis of sardine oil was studied. The derivatives of different lipases physically adsorbed on hydrophobic porous supports Hydrophobic Lipase Derivatives (HLD) were tested. These immobilized lipases can only hydrolyze oil molecules partitioned into the aqueous phase of a biphasic reaction system. HLD biocatalysts were compared to other enzyme derivatives that were obtained by very mild covalent immobilization on CNBr-activated Sepharose Cyanogen bromide Lipase Derivatives (CNLD) that behave almost identically to soluble enzymes (CNLD). In general, HLD biocatalysts were found to be more active and more selective for the release of eicosapentaenoic acid (EPA) than CNLD. The most interesting biocatalyst was the HLD derivative of Yarrowia lipolytica lipase, which was found to be sevenfold more active and tenfold more selective than CNLD. On the other hand, the most active (but non-selective) derivative was the HLD of Pseudomonas fluorescens lipase (PFL). The activity of this derivative was 0.6 International Units under non-optimal reaction conditions. High-loaded PFL derivatives could be very interesting for the release of mixtures of EPA and docosahexaenoic acid. Hydrophobic supports promote the interfacial activation of lipases, similar to the interaction promoted by oil drops on soluble enzymes. The most effective overactivation obtained in this work ranged from 6- to 20-fold. The hydrolytic process was carried out under very mild conditions (pH 7.0 and 25 °C), and all lipase derivatives remained fully active for at least 15 days under these conditions.