Marine microalgae Schizochytrium sp. have a high content of docosahexaenoic acid (DHA), an omega-3 fatty acid that is attracting interest since it prevents certain neurodegenerative diseases. The obtention of a bioactive and purified DHA fatty acid ester using a whole-integrated process in which renewable sources and alternative methodologies are employed is the aim of this study. For this reason, lyophilized Schizochytrium biomass was used as an alternative to fish oil, and advanced extraction techniques as well as enzymatic modification were studied. Microalgal oil extraction was optimized via a surface-response method using pressurized liquid extraction (PLE) obtaining high oil yields (29.06 ± 0.12%) with a high concentration of DHA (51.15 ± 0.72%). Then, the enzymatic modification of Schizochytrium oil was developed by ethanolysis using immobilized Candida antarctica B lipase (Novozym^® 435) at two reaction temperatures and different enzymatic loads. The best condition (40 °C and 200 mg of lipase) produced the highest yield of fatty acid ethyl ester (FAEE) (100%) after 8 h of a reaction attaining a cost-effective and alternative process. Finally, an enriched and purified fraction containing DHA-FAEE was obtained using open-column chromatography with a remarkably high concentration of 93.2 ± 1.3% DHA. The purified and bioactive molecules obtained in this study can be used as nutraceutical and active pharmaceutical intermediates of marine origin.

In the present work, borage oil (Borago officinalis) was used as the main source of gamma linolenic acid (GLA) to obtain ethyl esters by enzymatic ethanolysis using immobilized enzymes for its application in the food industry. Commercial Thermomyces lanuginosus lipase (TLL) was compared to chemical ethanolysis in alkaline medium. In addition, TLL was immobilized by adsorption on hydrophobic porous support (Octadecyl-Sepabeads^®) to compare the results. Fatty acid ethyl ester (FAEE) yields of both reactions were compared under the same conditions (25 °C and 200 rpm) and analyzed by GC-MS. Moreover, the conversion yield for borage oil ethanolysis catalyzed by TLL immobilized on C18-Sepabeads^® supports was similar to the chemical pathway (93.4% and 99.5%, respectively). When this biocatalyst was used in a solvent-free system (at 40 °C and 200 rpm), it was possible to obtain a high FAEE yield of 84.3% in the first 24 h of reaction. Furthermore, it was possible to re-use the immobilized biocatalyst for the performance of five reaction cycles maintaining 68% of its initial activity. Thus, the use of immobilized enzymes in solvent-free systems is an eco-friendly alternative to obtain GLA ethyl esters for its possible application in cosmetics and food.

Sustainable plant-based materials are becoming more popular as a substitute for those of animal origin for the encapsulation of compounds. Among different techniques, microencapsulation is widely used to protect bioactives and keep them intact to reach the desired target area. In this work, microencapsulation of oils by spray-drying using alternative vegan materials was proposed to mitigate oxidative degradation of oils. The determination of the best combination and ratio for different vegan wall materials (pectin, inulin, pea protein, and modified corn starch) was first developed using high-oleic sunflower oil enriched with β-carotene. In terms of efficiency, the best wall materials were pectin and inulin (P:I) in a 1:1 ratio, achieving 67.26 ± 0.78%. This ratio also obtained the best morphological results for shape and size studied by SEM (scanning electron microscopy) and DLS (dynamic light scattering). Additionally, the antioxidant activity of the oil enriched with β-carotene was studied, obtaining an IC5O of 0.15 mg/mL. Moreover, when Schizochytrium sp. was used instead of sunflower oil, as a docosahexaenoic acid (DHA)-enriched plant-based oil, the best results were also obtained for the P:I mixture, but at a ratio of 1:5. In all cases, the preservation of fatty acid profiles was achieved, giving insights for the potential use of alternative materials. The synergy between the use of antioxidants and encapsulation provides an effective method to avoid oxidation of edible oils. This work demonstrates the possibility of encapsulating carotenoid-enriched microalgae oil with vegan materials, improving its stability and bioavailability.