LIPASE-CATALYZED SYNTHESIS OF STRUCTURED LIPIDS IN POLAR SOLVENTS (original) (raw)
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Journal of the American Oil Chemists Society, 2012
The synthesis of medium-long-medium type structured lipids (SL) by the interesterification of tricaprylin (TC) and trilinolenin (TLN), using selected commercial lipases from Rhizomucor miehei (Lipozyme RM IM) and Candida antarctica (Novozym 435) was investigated. Although the bioconversion yield (BY) for Lipozyme RM IM (24.7 %) was close to that for Novozym 435 (24.0 %), the initial enzyme activity was 6.3 lmol CLnC/g enzyme/min and 1.6 lmol CLnC/g enzyme/min, respectively. Lipozyme RM IM was subsequently selected for further investigation. The structural analyses of SL indicated that the major products were 1,3-dicapryl-2-linolenyl glycerol (CLnC) and 1(3)-capryl-2,3(1)-dilinolenyl glycerol (CLnLn). In order to optimize the BY, selected parameters were investigated. The experimental results showed that using hexane as the reaction medium, at an initial water activity (a w) of 0.06, 10 mg solid enzyme/mL, substrate molar ratio of TC to TLN of 6:1 and a reaction time of 9 h, resulted in the highest BY (73.2 %). Using the optimized conditions, the effects of TLN concentration and other selective parameters, including the denaturation of the enzyme, controlling the a w and the addition of silica gel, on the mass productivity (P M), enzymatic productivity (P E) and volumetric productivity (P V) of the interesterification reaction, were also investigated.
Lipase-catalyzed acidolysis of tristearin with oleic or caprylic acids to produce structured lipids
Journal of Oil Fat Industries, 2012
Two different structured lipids (SL) were synthesized by transesterifying tristearin with caprylic acid (C8:0) or oleic acid (C18:1). The objective was to synthesize SL containing stearic acid (C18:0) at the sn-2 position as possible nutritional and low-calorie fats. The reaction was catalyzed by IM60 lipase from Rhizomucor miehei in the presence of n-hexane. The effects of reaction parameters affecting the incorporation of caprylic acid into tristearin were compared with those for incorporating oleic acid into tristearin. For all parameters studied, oleic acid incorporation was higher than caprylic acid. The range of conditions favorable for synthesizing high yields of C8:0-containing SL was narrower than for oleic acid. An incubation time of 12-24 h and an enzyme content of 5% (w/w total substrates) favored C8:0 incorporation. The mole percentage of incorporated C18:1 did not increase further at enzyme additions greater than 10%. C18:1 incorporation decreased with the addition of more than 10% water (w/w total substrates) to the tristearin-oleic acid reaction mixture. Increasing the mole ratio of fatty acid (FA) to triacylglycerol increased oleic acid incorporation. The highest C8:0 incorporation was obtained at a 1:6 mole ratio of tristearin to FA. Positional analysis confirmed that C18:0 remained at the sn-2 position of the synthesized SL. The melting profiles of tristearin-caprylic acid and tristearin-oleic acid SL displayed peaks between −20 to 30°C and −20 to 40°C, respectively. Their solid fat contents (~25%) at 25°C suggest possible use in spreads or for inclusion with other fats in specialized blends.
Enzyme and Microbial Technology, 1998
The study of triacylglycerol synthesis using 1,3-regiospecific-immobilized Rhizomucor miehei lipase as biocatalyst was performed under pure substrate conditions. Tritetradecanoylglycerol, trihexadecanoylglycerol, and trioctadecanoylglycerol were synthesized from glycerol and free fatty acids at a higher rate than medium-chain triacylglycerols such as tridecanoylglycerol and tridodecanoylglycerol. Furthermore, it is clearly shown that linolenic acid is esterified more slowly than oleic acid which is itself esterified more slowly than octadecanoic acid. The higher the number of unsaturation, the lower the rate of synthesis and the final yield. Under the tested conditions, trilinolenin synthesis cannot be achieved because secondary reactions such as polymerization took place.
Journal of Molecular Catalysis B: Enzymatic, 2012
Enzymatic modification of vegetable oils can be used to produce plastic fat or structured lipids (SL) avoiding the generation of trans fatty acids. Biocatalysts previously prepared by immobilization of Rhizomucor miehei lipases onto alkylated chitosan microspheres were used to synthesize SL by acidolysis reaction of sunflower oil and palmitic-stearic acids mixture. Effects of some reaction parameters, substrate molar ratio (SR), amount of biocatalyst (E) and amount of solvent (H), over selected response variables were analyzed by applying an incomplete factorial design of three factors with three levels (Box-Behnken). Responses were selected to evaluate not only the development of desired TAG but also the yield and quality of obtained products, through by-products and undesired trisaturated lipids quantification. The analysis of variable effects showed that E was the most significant factor on each analyzed response. Multiresponse optimization with restrictions from practical considerations revealed that maximum saturated fatty acids composition in glycerides of the SL (38.6%) is obtained when SR = 3, E = 0.34 g and H = 3.2 ml are used. Under these conditions, a change in the composition of the desired TAG group (monounsaturated TAG) from 2.5% in the original oil to 33.9% in the final product was achieved. On the other hand, time and temperature behavior studies showed that generation of trisaturated triacylglycerols and byproducts were favored mainly by increasing temperature. After 12 h of reaction, overall hydrolysis and esterification reactions rates were comparable. However, TAG distribution continued changing.
ENZYMATIC SYNTHESIS OF STRUCTURED LIPIDS: TRANSESTERIFICATION OF TRIOLEIN AND CAPRYLIC ACID
Journal of Food Lipids, 1995
Twelve commercially available lipases (I 0% , w/w substrates) were screened for their ability to form structured lipid by incubating 100 mg triolein and 65.3 mg caprylic acid in 3 ml hexane at 55C for 24 h. 7he products were analyzed by reverse-phase high pe$ormunce liquid chromatography (HPLC) with evaporative light scattering detection. Monocapryloolein was the major component of the products (57.4 mol %) and IM60 lipase from Rhizomucor miehei was the best biocatalyst. Dicapryloolein and triolein contents were 35.4% and 5.3 %, respectively. Temperature, mole ratio, time course, incubation media, added water, enzyme load, and substrate concentration were also investigated in this study. The results suggest that it is possible to synthesize structured lipids with lipase as biocatalyst.
Lipase-catalyzed synthesis of structured triacylglycerides from 1,3-diacylglycerides
Journal of the American Oil Chemists' Society, 2004
A new method for the lipase-catalyzed synthesis of structured TAG (ST) is described. First, sn1,3-dilaurin or-dicaprylin were enzymatically synthesized using different published methods. Next, these were esterified at the sn2-position with oleic acid or its vinyl ester using different lipases. Key to successful enzymatic synthesis of ST was the choice of a lipase with appropriate FA specificity, i.e., one that does not act on the FA already present in the sn1,3-DAG, but that at the same time exhibits high selectivity and activity toward the FA to be introduced. Reactions were performed in the presence of organic solvents or in solvent-free systems under reduced pressure. With this strategy, mixed ST containing the desired compounds 1,3-dicapryloyl-2-oleyl-glycerol or 1,3-dilauroyl-2-oleyl-glycerol (CyOCy or LaOLa) were obtained at 87 and 78 mol% yield, respectively, using immobilized lipases from Burkholderia cepacia (Amano PS-D) in n-hexane at 60°C. However, regiospecific analysis with porcine pancreatic lipase indicated that in CyOCy, 25.7% caprylic acid and in LaOLa 11.1% lauric acid were located at the sn2-position. Oleic acid vinyl ester was a better acyl donor than oleic acid. Esterification of sn1,3-DAG and free oleic acid gave very low yield (<20%) of ST in a solvent system and moderate yield (>50%) in a solvent-free system under reduced pressure.
Lipase Catalyzed Esters Syntheses in Organic Media: A Review
2012
Lipases (E.C. 3.1.1.3) from different sources have investigated for their hydrolytic as well as synthetic activity. The most desired characteristics of the lipase are its ability to utilize all mono-, di-, and tri-glycerides as well as the free fatty acids in transesterification, low product inhibition, high activity/ yield in non-aqueous media, low reaction time, resistance to altered temperature, pH, alcohol and reusability of immobilized enzyme. Clearly, lipases from different sources have different properties suitable for the process. Thus, there has been a search for an ideal enzyme which can work efficiently in organic media. Different strategies have been employed to improve the yield of the enzyme and to make the reaction time as short as possible. The optimum reaction conditions such as temperature, time duration and agitation speed are varied wholly and optimized with different combinations of the source of the lipase, the immobilization media, and alcohol used. Thermodyna...
Journal of The Brazilian Chemical Society, 2007
This work assessed the influence of important factors that affect the synthesis of glyceride esters in solvent-free systems, such as: glycerol/fatty acid molar ratio, lipase source and activating agent of the support obtained by the sol-gel technique. Commercial lipase preparations were immobilized on polysiloxane-polyvinyl alcohol particles (POS-PVA) previously activated with different agents (glutaraldehyde, sodium metaperiodate and carbonyldiimidazole) and their performance on the esterification reaction was compared with commercial preparations of immobilized lipase (Lipozyme IM20, Novozym 435, Lipozyme RM IM and Lipozyme TL IM). The reaction medium containing excess glycerol favored the glyceride ester synthesis and the Lipozyme IM20 was found to be the most suitable immobilized lipase preparation, attaining molar conversions higher than 94%. The use of CAL B Lipase immobilized on POS-PVA also provided satisfactory performance (conversion of about 80%) and allowed the formation of 36% wt of 2,3-dihydroxypropyl dodecanoate (monolaurin).