Concentration of docosahexaenoic and eicosapentaenoic acids by enzymatic alcoholysis with different acyl-acceptors

Efficient method of synthesizing sn-2 eicosapentaenoic acid (EPA) monoacylglycerols using circular ethanolysis and glycerolysis

The sn-2 monoacylglycerol (MAG) of eicosapentaenoic acid (EPA) can be used as a health-promoting ingredient in functional foods. However, the lack of a good recovery method to prepare high-purity 2-EPA MAGs has limited their application. In this study, circular ethanolysis and glycerolysis were repeated three times to synthesize 2-EPA MAGs and obtain a high recovery of EPA in them. Ethanolysis was carried out using 12 % of Lipozyme 435 and an ethanol-to-triacylglycerol (TAG) ratio of 60, which led to a TAG conversion rate of 97.3 %. Glycerolysis was then carried out using 16 % of CL "Amano" IM and a substrate-to-glycerol ratio of 9 (under vacuum), which led to a conversion rate of ethyl ester to TAGs of 96.8 %. After three ethanolysis-glycerolysis cycles, a relatively high recovery of EPA in the 2-MAG (72.1 %) was obtained. After purification, a high purity 2-EPA MAG product (EPA: 92.2 ± 1.8 %; 2-MAG: 91.50 ± 0.14 %) was obtained.

Utilization of Fusarium Solani lipase for enrichment of polyunsaturated Omega-3 fatty acids

Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), offer numerous health benefits. Enriching these fatty acids in fish oil using cost-effective methods, like lipase application, has been studied extensively. This research aimed to investigate F. solani as a potential lipase producer and compare its efficacy in enhancing polyunsaturated omega-3 fatty acids with commercial lipases. Submerged fermentation with coconut oil yielded Lipase F2, showing remarkable activity (215.68 U/mL). Lipase F2 remained stable at pH 8.0 (activity: 93.84 U/mL) and active between 35 and 70 °C, with optimal stability at 35 °C. It exhibited resistance to various surfactants and ions, showing no cytotoxic activity in vitro, crucial for its application in the food and pharmaceutical industries. Lipase F2 efficiently enriched EPA and DHA in fish oil, reaching 22.1 mol% DHA and 23.8 mol% EPA. These results underscore the economic viability and efficacy of Lipase F2, a partially purified enzyme obtained using low-cost techniques, demonstrating remarkable stability and resistance to diverse conditions. Its performance was comparable to highly pure commercially available enzymes in omega-3 production. These findings highlight the potential of F. solani as a promising lipase source, offering opportunities for economically producing omega-3 and advancing biotechnological applications in the food and supplements industry.

Microalgal polyunsaturated fatty acids: Hotspots and production techniques

Algae play a crucial role in the earth’s primary productivity by producing not only oxygen but also a variety of high-value nutrients. One such nutrient is polyunsaturated fatty acids (PUFAs), which are accumulated in many algae and can be consumed by animals through the food chain and eventually by humans. Omega-3 and omega-6 PUFAs are essential nutrients for human and animal health. However, compared with plants and aquatic sourced PUFA, the production of PUFA-rich oil from microalgae is still in the early stages of exploration. This study has collected recent reports on algae-based PUFA production and analyzed related research hotspots and directions, including algae cultivation, lipids extraction, lipids purification, and PUFA enrichment processes. The entire technological process for the extraction, purification and enrichment of PUFA oils from algae is systemically summarized in this review, providing important guidance and technical reference for scientific research and industrialization of algae-based PUFA production.

Future of Structured Lipids: Enzymatic Synthesis and Their New Applications in Food Systems

Structured lipids (SLs) refer to a new type of functional lipid obtained by modifying natural triacylglycerol (TAG) through the restructuring of fatty acids, thereby altering the composition, structure, and distribution of fatty acids attached to the glycerol backbones. Due to the unique functional characteristics of SLs (easy to absorb, low in calories, reduced serum TAG, etc.), there is increasing interest in the research and application of SLs. SLs were initially prepared using chemical methods. With the wide application of enzymes in industries and the advantages of enzymatic synthesis (mild reaction conditions, high catalytic efficiency, environmental friendliness, etc.), synthesis of SLs using lipase has aroused great interest. This review summarizes the reaction system of SL production and introduces the enzymatic synthesis and application of some of the latest SLs discussed/developed in recent years, including medium- to long-chain triacylglycerol (MLCT), diacylglycerol (DAG), EPA- and DHA-enriched TAG, human milk fat substitutes, and esterified propoxylated glycerol (EPG). Lastly, several new ways of applying SLs (powdered oil, DAG plastic fat, inert gas spray oil, and emulsion) in the future food industry are also highlighted.

Progress in enrichment of n-3 polyunsaturated fatty acid: a review

n-3 Polyunsaturated fatty acids (n-3 PUFA) has been widely used in foods, and pharmaceutical products due to its beneficial effects. The content of n-3 PUFA in natural oils is usually low, which decreases its added value. Thus, there is an increasing demand on the market for n-3 PUFA concentrates. This review firstly introduces the differences in bioavailability and oxidative stability between different types of PUFA concentrate (free fatty acid, ethyl ester and acylglycerol), and then provides a comprehensive discussion of different methods for enrichment of lipids with n-3 PUFA including physical-chemical methods and enzymatic methods. Lipases used for catalyzing esterification, transesterification and hydrolysis reactions play an important role in the production of highly enriched various types of n-3 PUFA concentrates. Lipase-catalyzed alcoholysis or hydrolysis reactions are the mostly employed method to prepare high-quality n-3 PUFA of structural acylglycerols. Although many important advantages offered by lipases in enrichment of n-3 PUFA, the high cost of enzyme limits its industrial-scale production. Further research should focus on looking for biological enzymes with extraordinary catalytic ability and clear selectivity. Other novel technologies such as protein engineering and immobilization may be needed to modify lipases to improve its selectivity, catalytic ability and reuse.

Kinetic study of a commercial lipase for hydrolysis of semi-refined oil of anchovy (Engraulis ringens) [Estudio cinético de una lipasa comercial para la hidrólisis de aceite semirrefinado de anchoa (Engraulis ringens)]

Lipases due to their ecological nature and catalytic versatility, are ideal for their application in the fish oil hydrolysis industry due to their selective property, which allows the preservation of polyunsaturated fatty acids (PUFAs) in the lipid structure. The objective of this research was to determine the activity and kinetic parameters of a commercial AY AMANO "30SD" lipase, as well as the temperature and time values ​​to achieve an optimal degree of hydrolysis in semi-refined anchovy oil. The experiments were carried out in a jacketed minireactor with a working volume of 400 mL (oil-water-enzyme) with temperature control and pH 7.00, enzyme concentration 350 U/mL and stirring 160 rpm. A 3x3 factorial design and the response surface methodology were used. The results obtained from the study of the enzyme were: activity = 37 384.55 ± 395.07 U/g and kinetic parameters: Km = 7.98 g/L and Vmax. = 0.038887 g/Lxmin. Correspondingly, the following optimal parameters were obtained: Degree of hydrolysis 4.01%, temperature 46.86 °C and hydrolysis time 90 minutes, with a confidence level of 95% (p <0.05). Conclusions: The study allowed us to kinetically characterize the commercial lipase and determine the optimum degree of hydrolysis of the semi-refined anchovy oil.

Integrated Production of Biodiesel and Concentration of Polyunsaturated Fatty Acid in Glycerides Through Effective Enzymatic Catalysis

DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) contained in glycerides have been reported to be more advantageous for their intake than their counterpart in the form of free fatty acid or fatty acid esters. This work attempts to achieve the flexible concentration of DHA and EPA in glycerides as well as biodiesel production via a two-step process catalyzed by lipases. In the first step, several commercial lipases were investigated and Novozym ET2.0 demonstrated the highest potential in selective concentration of DHA and EPA. Over 85% of EPA and other fatty acids were converted to its corresponding FAEEs (fatty acid ethyl esters), while over 80% of DHA remained in glycerides under the optimized conditions. After the first step ethanolysis, the oil phase was subject to molecular distillation and a 97.5% biodiesel (FAEE) content could be obtained. Further flexible enrichment of DHA and EPA in glycerides was realized by immobilized lipase Novozym 435-mediated transesterification of glycerides (remaining in the heavy phase after molecular distillation) with DHA- or EPA-rich EE, and glycerides with 67.1% DHA and 13.1% EPA, or glycerides with 41.1% EPA and 38.0% DHA could be obtained flexibly. This work demonstrated an effective approach for DHA and EPA enrichment combined with biodiesel production through enzymatic catalysis.

Efficient Biodiesel Conversion from Microalgae Oil of Schizochytrium sp

Abstract: Microalgae oil has been regarded as a promising feedstock for biodiesel production. However, microalgae oil usually contains some non-lipid components, such as pigments. Microalgae oil could be converted to biodiesel effectively with a two-step process to decrease the negative effect caused by by-product glycerol generated in traditional biodiesel production process. Firstly, microalgae oil was hydrolysed to free fatty acids (FFAs) and then FFAs were converted to methyl ester. In this study, the hydrolysis of microalgae oil from Schizochytrium sp. was systematically investigated and microalgae oil could be hydrolysed effectively to FFAs at both non-catalytic and acid-catalytic conditions. The hydrolysis degree of 97.5% was obtained under non-catalytic conditions of 220 °C and a water to oil ratio of 10:1 (w:w). The hydrolysis degree of 97.1% was obtained with the optimized sulphuric acid catalytic conditions of 95 °C, and a ratio of water to oil 3:1. The lipase Novozym435-mediated esterification with the hydrolysed FFAs was explored and a FAME (Fatty Acids Methyl Ester) yield of 95.1% was achieved. The conversion of different FFAs also was compared and the results indicated that lipase Novozym435-mediated methanolysis was effective for the preparation of biodiesel as well as poly unsaturated fatty acids (PUFAs).

Direct enzymatic ethanolysis of potential Nannochloropsis biomass for co-production of sustainable biodiesel and nutraceutical eicosapentaenoic acid

BACKGROUND

Marine microalga Nannochloropsis is a promising source for the production of renewable and sustainable biodiesel in replacement of depleting petroleum. Other than biodiesel, Nannochloropsis is a green and potential resource for the commercial production of nutraceutical eicosapentaenoic acid (EPA, C_20:5). In recent studies, low-value biodiesel can be achieved by transesterification of Nannochloropsis biomass. However, it is undoubtedly wasteful to produce microalgal biodiesel containing EPA from nutritional and economical aspects. A new strategy was addressed and exploited to produce low-value bulky biodiesel along with EPA enrichment via enzymatic ethanolysis of Nannochloropsis biomass with a specific lipase.

RESULTS

Cellulase pretreatment on Nannochloropsis sp. biomass significantly improved the biodiesel conversion by direct ethanolysis with five enzymes from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TL), Rhizomucor miehei (RM), and Aspergillus oryzae (PLA). Among these five biocatalysts, CALA was the best suitable enzyme to yield high biodiesel conversion and effectively enrich EPA. After optimization, the maximum biodiesel conversion (46.53-48.57%) was attained by CALA at 8:1 ethanol/biomass ratio (v/w) in 10-15% water content with 10% lipase weight at 35 °C for 72 h. Meanwhile, EPA (60.81%) was highly enriched in microalgae NPLs (neutral lipids and polar lipids), increasing original EPA levels by 1.51-fold. Moreover, this process was re-evaluated with two Nannochloropsis species (IMET1 and Salina 537). Under the optimized conditions, the biodiesel conversions of IMET1 and Salina 537 by CALA were 63.41% and 54.33%, respectively. EPA contents of microalgal NPLs were 50.06% for IMET1 and 53.73% for Salina 537.

CONCLUSION

CALA was the potential biocatalyst to discriminate against EPA in the ethanolysis of Nannochloropsis biomass. The biodiesel conversion and EPA enrich efficiency of CALA were greatly dependent on lipidic class and fatty acid compositions of Nannochloropsis biomass. CALA-catalyzed ethanolysis with Nannochloropsis biomass was a promising approach for co-production of low-value biodiesel and high-value microalgae products rich in EPA.

Highly Efficient and Enzyme-Recoverable Method for Enzymatic Concentrating Omega-3 Fatty Acids Generated by Hydrolysis of Fish Oil in a Substrate-Constituted Three-Liquid-Phase System

A novel three-liquid-phase system which contained fish oil as the nonpolar phase was developed for the lipase-based hydrolysis of fish oil and subsequent enrichment of the omega-3 polyunsaturated fatty acids (n-3 PUFA) in the glyceride fraction of the fish oil. In comparison with the traditional oil/water system, the enrichment factor of n-3 PUFA in this system was increased by 363.4% as a result of a higher dispersity, higher selectivity of the lipase for the other fatty acids except for n-3PUFA, and relief of product inhibition. The content of n-3 PUFA in the glyceride fraction could be concentrated to 67.97% by repeated hydrolysis after removing the free fatty acids. Furthermore, the lipase could be reused for at least eight rounds. This method would be an ideal approach for enriching n-3 PUFA because it is cost-effective, low in toxicity, and easily scaled up.

Highly concentrated omega-3 fatty acid ethyl esters by urea complexation and molecular distillation

BACKGROUND

Raya liver deodorized oil contains high concentrations of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). The present study investigated the processes of urea complexation (UC) and molecular distillation (MD) to determine the most adequate operation conditions for each process, separately and together, aiming to obtain highly concentrated EPA, DPA and DHA ethyl esters with chemical indicator values permitted by the current legislation for edible oils.

RESULTS

In the second stage of MD, a concentration of 820.27 g kg^-1 in the distillate and 951.06 g kg^-1 of omega-3 fatty acid ethyl esters in the residue was obtained. The distillate showed values of free fatty acids, peroxide and p-anisidine lower than the maximum allowed for edible oils in accordance with the current legislation.

CONCLUSION

The use of UC and MD together has revealed a significant improvement in the total concentration of omega-3 fatty acid ethyl esters in the final product and good application prospects. © 2018 Society of Chemical Industry.

Lipase-catalyzed selective enrichment of omega-3 polyunsaturated fatty acids in acylglycerols of cod liver and linseed oils: Modeling the binding affinity of lipases and fatty acids

Present study employed molecular modeling method to elucidate the binding affinity of lipases with fatty acids of different chain lengths; and investigated the effects of lipases positional and fatty acids specificity on omega-3 polyunsaturated fatty acids (ω-3 PUFAs) enrichment in cod liver and linseed oils. Among the lipases studied, molecular modeling showed the active sites of Candida rugosa lipase (CRL) had a low C-Docker interactive energy for saturated (SFA) and monounsaturated (MUFA) fatty acids which predicted CRL to have highest preferences to selectively hydrolyze resulting in efficient enrichment of ω-3 PUFAs. Verification experiments showed the SFA and MUFA in the acylglycerol fraction includes monoacylglcyerols (MAG), diacyglycerols (DAG), and triacylglycerols (TAG) of CRL-hydrolyzed cod liver oil decreased from the initial 25.21 to 16.88% and 45.25 to 32.17%, respectively. In addition, CRL-hydrolyzed cod liver oil demonstrated 88.36% of ω-3 PUFAs enrichment. The regio-distribution of fatty acids in CRL-hydrolyzed cod liver oil were not significantly different than that of cod liver oil indicating the ω-3 PUFAs enrichment was due to fatty acids selectivity and not positional selectivity of CRL.

Two-Stage Enzymatic Preparation of Eicosapentaenoic Acid (EPA) And Docosahexaenoic Acid (DHA) Enriched Fish Oil Triacylglycerols

Fish oil products in the form of triacylglycerols generally have relatively low contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and so it is of potential research and industrial interest to enrich the related contents in commercial products. Thereby an economical and efficient two-stage preparation of EPA and DHA enriched fish oil triacylglycerols is proposed in this study. The first stage was the partial hydrolysis of fish oil by only 0.2 wt.‰ AY "Amano" 400SD which led to increases of EPA and DHA contents in acylglycerols from 19.30 and 13.09 wt % to 25.95 and 22.06 wt %, respectively. Subsequently, products of the first stage were subjected to transesterification with EPA and DHA enriched fatty acid ethyl esters (EDEE) as the second stage to afford EPA and DHA enriched fish oil triacylglycerols by using as low as 2 wt % Novozyme 435. EDEEs prepared from fish oil ethyl ester, and recycled DHA and EPA, respectively, were applied in this stage. Final products prepared with two different sources of EDEEs were composed of 97.62 and 95.92 wt % of triacylglycerols, respectively, with EPA and DHA contents of 28.20 and 21.41 wt % for the former and 25.61 and 17.40 wt % for the latter. Results not only demonstrate this two-stage process's capability and industrial value for enriching EPA and DHA in fish oil products, but also offer new opportunities for the development of fortified fish oil products.

Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification

In order to obtain microalgal saponifiable lipids (SLs) fractions containing different polar lipid (glycolipids and phospholipids) contents, SLs were extracted from wet Nannochloropsis gaditana microalgal biomass using seven extraction systems, and the polar lipid contents of some fractions were reduced by low temperature acetone crystallization. We observed that the polar lipid content in the extracted lipids depended on the polarity of the first solvent used in the extraction system. Lipid fractions with polar lipid contents between 75.1% and 15.3% were obtained. Some of these fractions were transformed into fatty acid methyl esters (FAMEs, biodiesel) by methanolysis, catalyzed by the lipases Novozym 435 and Rhizopus oryzae in tert-butanol medium. We observed that the reaction velocity was higher the lower the polar lipid content, and that the final FAME conversions achieved after using the same lipase batch to catalyze consecutive reactions decreased in relation to an increase in the polar lipid content.