Enzymatic modification of evening primrose oil: Incorporation of n−3 polyunsaturated fatty acids

Tuning of essential oil properties by enzymatic treatment: towards sustainable processes for the generation of new fragrance ingredients

In this review, several strategies of modification of essential oils by enzymatic treatment are presented. Being either applied before or after the production of the essential oil, enzymatic methods are shown to be particularly adapted to attain the required selectivity, specificity and efficiency in sustainable processes delivering products eligible for the natural grade. Examples dealing with the optimization of the properties of essential oils in terms of biological activity, odor and safety are provided, and it is likely that these strategies will address other type of properties in the future, such as the physico-chemical properties, for example.

Purification and biochemical characterization of an extracellular lipase from Pseudomonas fluorescens MTCC 2421

An extracellular lipase produced by Pseudomonas fluorescens MTCC 2421 was purified 184.37-fold with a specific activity of 424.04 LU/mg after anion exchange and gel exclusion chromatography. The enzyme is a homomeric protein with an apparent molecular mass of 65.3 kDa. The lipase exhibited hydrolytic resistance toward triglycerides with longer fatty acyl chain length containing unsaturation as evident from the lower V(max) (0.23 mM/mg/min) of the lipase toward glycerol trioleate (C(18:1n9)) compared with the fatty acid triglycerides having short to medium carbon chain lengths (C(18:0-12:0), V(max) 0.32-0.51 mM/mg/min). This indicates a preferential specificity of the lipase toward cleaving shorter carbon chain length fatty acid triglycerides. The lipase exhibited optimum activity at 40 degrees C and pH 8.0, respectively. A combination of Ca(2+) and sorbitol induced a synergistic effect on the thermostability of lipase with a significantly high residual activity (100%) after 30 min at 40 degrees C, as compared to 90.6% after incubation with Ca(2+) alone. The lipase activity was inhibited by Cu(2+) and Fe(2+) (42 and 48%, respectively) at 10 mM. The enzyme lost 31% of its initial activity by 0.001 mM EDTA and 42% by 0.1 mM EDTA. Significant reduction in lipase activity was apparent by 2-mercaptoethanol and phenylmethanesulfonyl fluoride at diluted concentration (0.001 mM), thereby indicating an important role of sulfhydryl groups in the catalytic mechanism.

Enrichment of eicosapentaenoic acid from sardine oil with Delta5-olefinic bond specific lipase from Bacillus licheniformis MTCC 6824

Lipase derived from Bacillus licheniformis MTCC 6824 was purified to homogeneity by anion exchange chromatography on Amberlite IRA 410 (Cl-) and gel filtration using Sephadex G-100 as judged by denaturing polyacrylamide gel electrophoresis. The purified lipase was used for hydrolysis of triacylglycerol in sardine oil to enrich Delta5-polyunsaturated fatty acids (Delta5-PUFAs) namely, arachidonic acid (5,8,11,14-eicosatetraenoic acid, ARA, 20:4n-6) and eicosapentaenoic acid (5,8,11,14,17-eicosapentaenoic acid, EPA, 20:5n-3). The individual fatty acids were determined as fatty acid methyl esters (FAMEs) by gas-liquid chromatography and gas chromatography-mass spectroscopy as FAMEs and N-acyl pyrrolidides. The enzyme exhibited hydrolytic resistance toward ester bonds of Delta5-PUFAs as compared to those of other fatty acids and was proved to be effective for increasing the concentration of EPA and ARA from sardine oil. Utilizing this fatty acid specificity, EPA and ARA from sardine oil were enriched by lipase-mediated hydrolysis followed by urea fractionation at 4 degrees C. The purified lipase produced the highest degree of hydrolysis for SFAs and MUFAs (81.5 and 72.3%, respectively, from their initial content in sardine oil) after 9 h. The profile of conversion by lipase catalysis showed a steady increase up to 6 h and thereafter plateaued down. Lipase-catalyzed hydrolysis of sardine oil followed by urea adduction with methanol provided free fatty acids containing 55.4% EPA and 5.8% ARA, respectively, after complexation of saturated and less unsaturated fatty acids. The combination of enzymatic hydrolysis and urea complexation proved to be a promising method to obtain highly concentrated EPA and ARA from sardine oil.

Biosynthesis and regulation of microbial polyunsaturated fatty acid production

Growing interest in polyunsaturated fatty acid (PUFA) applications in various fields coupled with their significance in health and dietary requirements has focused attention on the provision of suitable sources of these compounds. Isolation of highly efficient oleaginous microorganisms has led to the development of fermentation technologies as an alternative to agricultural and animal processes. Particularly active in PUFA synthesis are the Zygomycetes fungi and certain microalgae. Emphasis is placed on increasing the product value by employing new biotechnological strategies (e.g. mutation techniques, molecular engineering and biotransformations) which allow the regulation of microbial PUFA formation with satisfactory yield in order to be competitive with other sources. Comparative successes in fungal PUFA production demonstrate microbial potential to synthesize high-value oils and provide the main stimulus for their applications.

Process-induced changes in edible oils

Lipids are one of the main dietary components that serve several functions in foods and nutrition. They could be endogenous or deliberately included in food. The basic molecules of lipids undergo different chemical reactions during refining, processing and storage. Some of these chemical reactions enhance the usage and functionality of food lipids. This chapter discusses the chemical changes of lipids during various processing operations. Specific changes in the minor constituents of lipids are also included.

Polyunsaturated fatty acids, Part 2: Biotransformations and biotechnological applications

The realization of the important biomedical roles of polyunsaturated fatty acids has led to the development of methods for obtaining and manipulating polyunsaturated lipids. Enzyme-mediated reactions have demonstrated unique advantages over chemical approaches and commercial lipase- and phospholipase-catalysed processes have been developed to address the mid- to high-value polyunsaturated-lipid market. Research over the past two decades has also highlighted the broad spectrum of bioactive products derived from the oxidation of polyunsaturated fatty acids. The potential of these compounds in the flavour, fragrance, pharmaceutical and fine-chemical arenas has encouraged the elaboration of biotransformation strategies based on isolated enzymes and whole cells.