Sustainable Synthesis of Omega-3 Fatty Acid Ethyl Esters from Monkfish Liver Oil

Exploring the use of fatty acid ethyl esters as a potential natural solution for the treatment of fish parasitic diseases

Alternatives to conventional chemical treatments for parasitic diseases in fish are needed. Microalgal-sourced fatty acid ethyl esters (FAEEs) have shown an antiparasitic effect against Gyrodactylus turnbulli infection in guppies. Here, we tested a range of commercial FAEEs of various carbon chain lengths and unsaturation levels against two fish parasites. Guppies and barramundi infected with G. turnbulli and Trichodina sp., respectively, were used. The most effective FAEE, after excluding those toxic to fish, was ethyl laurate (12:0). For both parasites, the LD50 was 18.75 μM within 250 min of incubation. Ethyl eicosapentaenoate (20:5n3) was the next most effective FAEE against G. turnbulli, and dihomo-γ-linolenic acid ethyl ester (20:3n6) and ethyl α-linolenate (18:3n3) were the next most effective against Trichodina sp. In addition, FAEEs prepared from the microalga Phaeodactylum tricornutum residue, after fucoxanthin extraction, were examined against Trichodina sp. infection in barramundi for the first time. LD85 and LD100 was achieved at 2.5 and 5 μL mL-1 of the FAEE preparation, respectively. In vivo, immersion of infected barramundi in 1.25 μL mL-1 of this preparation for 24 h reduced infection prevalence from 100% to 53% and was non-toxic to fish.

Potential authentication of re-esterified triacylglycerol-type omega-3 oils using multivariate analysis of lipid profiles

This study aimed to authenticate re-esterified triacylglycerol (rTG)-type omega-3 oils prone to adulteration with fatty acid ethyl ester (FAEE)-type oils via hierarchical cluster analysis (HCA) and principal component analysis (PCA) of their lipid profiles. A total of 104 rTG-type omega-3 oil samples, consisting of seven authentic (two commercial and five laboratory-made), 60 adulterated, and 37 unauthenticated commercial samples, were analyzed for their acylglycerol, FAEE, and total EPA/DHA contents. Type 1 authentic samples contained higher triacylglycerols (TG) (63.0-86.3 wt%), lower diacylglycerols (DG) (8.1-31.5 wt%), and no FAEE compared to type 2 authentic samples (36.9-62.1 wt% TG, 9.4-36.9 wt% DG, and 14.9-27.3 wt% FAEE). HCA and PCA differentiated authentic samples from adulterated samples, although type 2 samples were closer to adulterated samples. Both analyses showed that 30/37 commercial samples exhibited higher similarity in lipid profiles to authentic samples than to adulterated samples, indicating their potential for authentication.

Efficient Expression and Application of a Modified Rhizomucor miehei Lipase for Simultaneous Production of Biodiesel and Eicosapentaenoic Acid Ethyl Ester from Nannochloropsis Oil

Few reports exist on one-step enzymatic methods for the simultaneous production of biodiesel and eicosapentaenoic acid ethyl ester (EPA-EE), a high-value pharmaceutical compound. This study aimed to efficiently express Rhizomucor miehei lipase (pRML) in Pichia pastoris X-33 via propeptide mutation and high-copy strain screening. The mutated enzyme was then used to simultaneously catalyze the production of both biodiesel and EPA-EE. The P46N mutation in the propeptide (P46N-pRML) significantly boosted its production, with the four-copy strain increasing enzyme yield by 3.7-fold, reaching 3425 U/mL. Meanwhile, its optimal temperature increased to 45-50 °C, pH expanded to 7.0-8.0, specific activity doubled, Km reduced to one-third, and kcat/Km increased 7-fold. Notably, P46N-pRML efficiently converts Nannochloropsis gaditana oil's eicosapentaenoic acid (EPA). Under optimal conditions, it achieves up to 93% biodiesel and 92% EPA-EE yields in 9 h. Our study introduces a novel, efficient one-step green method to produce both biodiesel and EPA-EE using this advanced enzyme.

Immobilized lipase for sustainable hydrolysis of acidified oil to produce fatty acid

Acidified oil is obtained from by-product of crops oil refining industry, which is considered as a low-cost material for fatty acid production. Hydrolysis of acidified oil by lipase catalysis for producing fatty acid is a sustainable and efficient bioprocess that is an alternative of continuous countercurrent hydrolysis. In this study, lipase from Candida rugosa (CRL) was immobilized on magnetic Fe₃O₄@SiO₂ via covalent binding strategy for highly efficient hydrolysis of acidified soybean oil. FTIR, XRD, SEM and VSM were used to characterize the immobilized lipase (Fe₃O₄@SiO₂-CRL). The enzyme properties of the Fe₃O₄@SiO₂-CRL were determined. Fe₃O₄@SiO₂-CRL was used to catalyze the hydrolysis of acidified soybean oil to produce fatty acids. Catalytic reaction conditions were studied, including amount of catalyst, reaction time, and water/oil ratio. The results of optimization indicated that the hydrolysis rate reached 98% under 10 wt.% (oil) of catalyst, 3:1 (v/v) of water/oil ratio, and 313 K after 12 h. After 5 cycles, the hydrolysis activity of Fe₃O₄@SiO₂-CRL remained 55%. Preparation of fatty acids from high-acid-value by-products through biosystem shows great industrial potential.

Special Issue on “Applied Biocatalysis in Europe: A Sustainable Tool for Improving Life Quality”

Applied biocatalysis, i [...]