Incorporation Of FA Research Articles

Antibacterial Activity of Fusidic Acid and Sodium Fusidate Nanoparticles Incorporated in Pine Oil Nanoemulgel.

PurposeFusidic acid (FA) and sodium fusidate (SF) have problems in their skin penetration and stability resulting in a reduction in their potency; therefore, the objective of this study was to develop FA and SF nanoemulgels to improve the antibacterial activity of the drugs.MethodsFA and SF nanoemulgel formulations were prepared by the incorporation of FA and SF nanoemulsions with Carbopol hydrogel. First, the drugs were screened for their solubility in different oils and surfactants to choose the suitable oil and surfactants for the drugs, and then the drug nanoemulsion formulations were prepared by a self-nanoemulsifying technique using Tween 80, Span 20 and pine oil. The drug nanoemulgels were evaluated for their particle size, polydispersity index (PDI), rheological behaviour, drug release and anti-microbial activity.ResultsBased on the solubility test, pine oil was the best solubilising oil for both drugs, Tween 80 and Span 20 showed the highest solubilising ability for both the drugs among the surfactants; therefore, they were chosen as surfactant and co-surfactant, respectively. The optimum self-nanoemulsifying formulations showed a particle size for fusidic acid and Sodium fusidate of 140.58 nm and 151.86 nm respectively, and both showed a low PDI below 0.3. After incorporating both drug SNEDDS formulations with Carbopol at different concentrations, the results of the drugs particle size and PDI showed no significant difference. The zeta potential results for both drugs nanoemulgels showed a negative potential with more than 30 mV. All nanoemulgel formulations showed pseudo-plastic behaviour with the highest release pattern at 0.4% Carbopol. The antibacterial activity of both drug nanoemulgel formulations showed superiority over the market product.ConclusionNanoemulgel is a promising delivery system for FA and SF that helps in improving the stability and antibacterial activities of the drugs.

Effect of curing temperature and fly ash content on the hydration and microstructure of fly ash–cement pastes

The effect of FA and curing temperature on the hydration and microstructure of FC pastes were studied by means of XRD, 29Si NMR and SEM. The results showed that with increasing FA content, the hydration degree of FA decreases, whereas the hydration of cement was accelerated. The incorporation of FA leads to an increase in the substitution fraction of Si4+ by Al3+ in aluminosilicate chains (Al[4]/Si) and also an increase in the mean aluminosilicate chain length of C-S-H gel (MCL). In the FC pastes with 30% FA cured for 28 d, with the increase of curing temperature, there is an overall increase in the MCL , the Al[4]/Si, the hydration degree of cement and the hydration degree of FA. This validated that the higher curing temperature favor more to enhance the hydration of cement, the pozzolanic reaction of FA and the polymerization of C-S-H gel for accelerated ion diffusion rate.

Effects of autoclave curing and fly ash on mechanical properties of ultra-high performance concrete

This study investigated compressive strength, flexural strength and fracture toughness of ultra-high performance concretes (UHPC) containing silica fume and different dosage of fly ash (0%, 10%, 20% and 30%) after exposure to different autoclave curing conditions with pressure of 0.5 MPa, 1.0 MPa and 1.5 MPa and duration time of 6 h, 8 h, 10 h and 12 h. The microstructure of UHPC samples were also measured by using MIP, XRD and SEM. The results show that the mechanical strength of UHPC specimen presents an increasing at first stage and a decreasing or stable trend later with the higher pressure or the prolonged duration time of autoclaving. The increasing autoclave pressure is needed for UHPC containing more fly ash to obtain the best strength. Incorporation of steel fibers could improve flexural strength while has little impact on compressive strength and the reinforcement effect of steel fibers gets more significant as the increasing autoclave pressure and duration. Autoclave curing degrades the fraction toughness for pure cement UHPC and the incorporation of FA can counteract or even eliminate this detrimental effect. The incorporation of fly ash and the increasing autoclave duration reduce the porosity of UHPC samples. The autoclave curing leads to the formation of xonotlite (Ca6[Si6O17](OH)2) and decreases the content of portlandite in UHPC samples.

Suitability of Fly Ash Vermicompost as a Component of Pine Bark Growing Media: Effects on Media Physicochemical Properties and Ornamental Marigold (Tagetes spp.) Growth and Flowering

ABSTRACTThis study evaluated the possibility of mixing fly ash vermicompost (FA) with pine bark (PB) compost to produce a horticultural growing medium for ornamental plants using ornamental marigolds (Tagetes spp.) as the test crop. Fly ash vermicompost was mixed with pine bark compost at 0, 25, 50, 75, and 100% and marigold seeds were sown with or without fertilizer in the resultant media to test their suitability as seedling growing media. FA substitution up to 50% significantly improved water-holding capacity, total porosity, and air-filled porosity. It also raised pH from 4.52 to a maximum of 8.33 when incorporated up to 75%. Incorporation of FA up to 75% resulted in significantly high germination percentages above 90% compared to only 22.5% for the 100% PB medium. However, after 4 weeks of growth, seedlings in the 25 and 50% FA substituted media had higher plant height and leaf area. The 25% FA treatment resulted in significantly higher number of flowers and buds compared to the 50 and 75%. For effective marigold seedling germination and growth, a 50% FA:50% PB growing medium is recommended while for maturity and flower production, the 25% FA:75% PB combination is preferred.

Bioavailability of n-3 fatty acids from n-3-enriched foods and fish oil with different oxidative quality in healthy human subjects: a randomised single-meal cross-over study.

Regular consumption of long-chain n-3 fatty acids (LC n-3 FA) reduces postprandial triacylglycerolaemia. Functional foods and supplements are alternative sources of LC n-3 FA; however, emulsification technologies, food matrices and altered lipid oxidation levels affect their bioavailability. Moreover, which functional foods are optimal LC n-3 FA carriers is unknown. The aim of the study was to determine the bioavailability of LC n-3 FA and the postprandial TAG response after the intake of oxidised or non-oxidised cod liver oil and after the intake of emulsified or non-emulsified LC n-3 FA using novel functional food items as LC n-3 FA carriers in a randomised cross-over acute study. A total of twenty-four healthy subjects completed the study in which subjects consumed one of four different test meals containing 1·5g LC n-3 FA, or a control meal with no LC n-3 FA. Postprandial TAG-rich lipoproteins were isolated and their fatty acid composition was measured. The LC n-3 FA from emulsified foods were more rapidly incorporated into TAG-rich lipoproteins compared with non-emulsified foods. The incorporation of LC n-3 FA was similar for oils emulsified in yogurt or juice and was unaffected by the oxidative status of the oil. Postprandial TAG levels did not differ among the various test meals. In conclusion, emulsification increases the bioavailability of LC n-3 FA through a more rapid incorporation into TAG-rich lipoproteins, and juice and yogurt are equally suited as LC n-3 FA carriers. The acute intake of oxidised cod liver oil does not influence the incorporation of LC n-3 FA into TAG-rich lipoproteins.

Mechanisms of triglyceride accumulation in activated macrophages

LPS treatment of macrophages induces TG accumulation, which is accentuated by TG-rich lipoproteins or FFA. We defined pathways altered during macrophage activation that contribute to TG accumulation. Glucose uptake increased with activation, accompanied by increased GLUT1. Oxidation of glucose markedly decreased, whereas incorporation of glucose-derived carbon into FA and sterols increased. Macrophage activation also increased uptake of FFA, associated with an increase in CD36. Oxidation of FA was markedly reduced, whereas the incorporation of FA into TGs increased, associated with increased GPAT3 and DGAT2. Additionally, macrophage activation decreased TG lipolysis; however, expression of ATGL or HSL was not altered. Macrophage activation altered gene expression similarly when incubated with exogenous FA or AcLDL. Whereas activation with ligands of TLR2 (zymosan), TLR3 (poly I:C), or TLR4 (LPS) induced alterations in macrophage gene expression, leading to TG accumulation, treatment of macrophages with cytokines had minimal effects. Thus, activation of TLRs leads to accumulation of TG in macrophages by multiple pathways that may have beneficial effects in host defense but could contribute to the accelerated atherosclerosis in chronic infections and inflammatory diseases.

Compressive Strength of Binary and Ternary Blended Cement Mortars Containing Fly Ash and Silica Fume under Autoclaved Curing

Cement industry is a one of the major sources of environmental pollution therefore the reduction of cement demand should be improved. Fly ash and silica fume is a by-product of industries and it should be reused to reduce the waste pollution. Thus, this study investigated the use of fly ash and silica fume as a cement replacement in binary and ternary blended cements on compressive strength and physical properties of mortar. Autoclaved curing at 130 °C and 20 psi of pressure for 9 h was used in this study. The results show that the compressive strength of binary blended cement mortar with FA tends to decrease with increased FA replacement and shows compressive strength lower than PC control. However, compressive strength of binary blended cement mortar with SF was improved and shows compressive strength higher than that of PC control. The compressive strength of ternary blended cement mortar was higher than binary blended cement at the same level replacement and it increases with increased SF replacement. Moreover, ternary blended cement mortar containing 10%SF by weight contribute in giving compressive strength higher than PC control. The incorporation of FA with SF can enhance workability of blended cement mortar containing only SF replacement.

Aspirin reduces hypertriglyceridemia by lowering VLDL-triglyceride production in mice fed a high-fat diet

Systemic inflammation is strongly involved in the pathophysiology of the metabolic syndrome, a cluster of metabolic risk factors that includes hypertriglyceridemia. Aspirin treatment lowers inflammation via inhibition of NF-κB activity but also reduces hypertriglyceridemia in humans. The aim of this study was to investigate the mechanism by which aspirin improves hypertriglyceridemia. Human apolipoprotein CI (apoCI)-expressing mice (APOC1 mice), an animal model with elevated plasma triglyceride (TG) levels, as well as normolipidemic wild-type (WT) mice were fed a high-fat diet (HFD) and treated with aspirin. Aspirin treatment reduced hepatic NF-κB activity in HFD-fed APOC1 and WT mice, and in addition, aspirin decreased plasma TG levels (-32%, P < 0.05) in hypertriglyceridemic APOC1 mice. This TG-lowering effect could not be explained by enhanced VLDL-TG clearance, but aspirin selectively reduced hepatic production of VLDL-TG in both APOC1 (-28%, P < 0.05) and WT mice (-33%, P < 0.05) without affecting VLDL-apoB production. Aspirin did not alter hepatic expression of genes involved in FA oxidation, lipogenesis, and VLDL production but decreased the incorporation of plasma-derived FA by the liver into VLDL-TG (-24%, P < 0.05), which was independent of hepatic expression of genes involved in FA uptake and transport. We conclude that aspirin improves hypertriglyceridemia by decreasing VLDL-TG production without affecting VLDL particle production. Therefore, the inhibition of inflammatory pathways by aspirin could be an interesting target for the treatment of hypertriglyceridemia.

Synthesis of Poly(α,β-[N-(2-hydroxyethyl)-L-aspartamide])-folate for Drug Delivery

Poly(α,β-[N-(2-hydroxyethyl)-L-aspartamide])-folate (PHEA-FA) was synthesized by linking FA to a poly(α,β-[N-(2-hydroxyethyl)-L-aspartamide]) (PHEA) backbone. The chemical structure of PHEA-FA was characterized by 1H-NMR and FT-IR. The molecular weights of the polymers were determined by combined size-exclusion chromatography and multiangle laser light scattering (SEC–MALLS) analysis. Due to the incorporation of FA, PHEA-FA exhibited pH-sensitive aggregation behavior in aqueous media. As characterized by UV-Vis spectroscopy and fluorescence spectroscopy, PHEA-FA could self-assemble to form aggregates in acidic and neutral aqueous solutions, and became soluble in a basic solution. The potential application of PHEA-FA in drug delivery was explored. Drug-loaded PHEA-FA nanoparticles were fabricated and the in vitro drug release of the drug-loaded nanoparticles was investigated. Transmission electron microscopy (TEM) showed that the nanoparticles exhibited a spherical morphology with particle sizes <100 nm. The in vitro study showed PHEA-FA exhibited enhanced cell uptake on the folate-receptor-positive cells because of the folate-mediated targeting.

STUDY OF NANO-SILICA/FLUORINATED ACRYLATE COPOLYMER HYBRID EMULSION AND THE POLYMERIZATION KINETICS

Perfluorinated polymers are of high scientific and technological interest owing to their unique characteristics.However,their utilization is limited due to their poor cohesiveness,film-forming properties and high cost.When perfluorinated polymers are incorporated with polyacrylate,remarkable properties are exhibited with higher performance price ratio;that is,oil and water repellency of the former is unmitigated while the mechanical strength and cohesiveness of the latter are retained.As an inexpensive functional component,incorporated silica can shield polymeric matrix from the UV,while reinforcement and improved thermal stability are achieved,as well as better rinse-resistance,perdurability and self-cleanness effects. In this paper,nano-silica and poly(MMA-co-nBAco-FA) were combined with covalent bonds.Not only extraordinary properties derived from each individual component were retained,but also a more intimate cooperation was provided between the twos,through an environment-friendly method. At first,the monodisperse silica was prepared in ethanol according to the well-known Stber procedure,followed by modification via addition of γ-methacryloxy propyltrimethoxysilane(MPS).Then,the nano-silica/poly(MMA-co-nBA-co-FA) hybrid emulsion was prepared via in-situ emulsion polymerization in the presence of MPS-grafted silica. The chemical compositions and morphologies of both nano-silica and silica/poly(MMA-co-nBA-co-FA) nanocomposites(NPs) were characterized by Fourier-transform infrared(FT-IR) spectrometry and transmission electron microscopy(TEM),respectively.From TEM images,it was obvious that uniform spherical nano-silica was obtained,with average diameter of 20 nm.FT-IR effectively proved the occurrence of MPS-grafting reaction.According to the amount of MPS added,the MPS-grafted density of nano-silica was determinated as 0.1716 μmol/m~2. Off-centre core-shell structures of silica/poly(MMA-co-nBA-co-FA) NPs were confirmed by TEM images.Approximately 50% of NPs had more than one single core due to the congregating of smaller particles when the diameters of the core were not larger than 100 nm.Under a low MPS-grafted density,not all of monomers were polymerized and connected with MPS on the grafted silica,and most of the polymer chains were twisted and absorbed around the core particles,followed by copolymerization with polymer layer copolymerized with MPS,resulted in an off-centre core-shell structure ultimately. Thermal stability of silica/poly(MMA-co-nBAco-FA) NPs was studied via thermal gravimetric analysis(TGA).The results showed that higher initiative decompose temperature was achieved with more nano-silica incorporated,which implicated the successful encapsulation of silica into NPs,as well as enhanced thermal stability. The surface properties of the latex films produced from silica/poly(MMAco-nBA-co-FA) NPs were also investigated by contact angle method and water absorption measurements.Obviously,the incorporation of silica and FA contributed to degressive surface-free energy,with a minimum value of 9.8 mN/m.Similarly,water absorption ratio decreased with increasing contents of nano-silica and FA.What worth noting was the abnormal polar and disperse component of surface-free energy,which might be attributed to nano-silica's incorporation and distribution while film-forming.Besides these,the kinetics of in situ emulsion polymerization,in which MPSgrafted silica with a low grafted density was introduced,had been investigated in details.The results can be summarized as follows: R_p∝~(0.25)[SiO_2]~(0.31)[I]~(0.66)~(0.757) while [SiO_2]8.9×10~-2 mol·L~-1,and R_p∝~(0.25)[SiO_2]~(-1.33)[I]~(0.66)[E]~(0.757) while [SiO_2]8.9×10~-2 mol·L~-1.The overall activation energy of the polymerization was calculated to be 83.15 kJ/mol.

Metabolism of apical versus basolateral sn-2-monoacylglycerol and fatty acids in rodent small intestine

The metabolic fates of radiolabeled sn-2-monoacylglycerol (MG) and oleate (FA) in rat and mouse intestine, added in vivo to the apical (AP) surface in bile salt micelles, or to the basolateral (BL) surface via albumin-bound solution, were examined. Mucosal lipid products were quantified, and the results demonstrate a dramatic difference in the esterification patterns for both MG and FA, depending upon their site of entry into the enterocyte. For both lipids, the ratio of triacylglycerol to phospholipid (TG:PL) formed was approximately 10-fold higher for delivery at the AP relative to the BL surface. Further, a 3-fold higher level of FA oxidation was found for BL compared with AP substrate delivery. Incorporation of FA into individual PL species was also significantly different, with >2-fold greater incorporation into phosphatidylethanolamine (PE) and a 3-fold decrease in the phosphatidylcholine:PE ratio for AP- compared with BL-added lipid. Overnight fasting increased the TG:PL incorporation ratio for both AP and BL lipid addition, suggesting that metabolic compartmentation is a physiologically regulated phenomenon. These results support the existence of separate pools of TG and glycerolipid intermediates in the intestinal epithelial cell, and underscore the importance of substrate trafficking in the regulation of enterocyte lipid metabolism.

Enzymatic Incorporation of Selected Long‐Chain Fatty Acids into Triolein

AbstractAcidolysis of triolein (tri C18:1) with selected long‐chain fatty acids (LCFA) was carried out using Candida antarctica (Novozym 435), Rhizomucor miehei (Lipozyme RM IM), Pseudomonas sp. (PS‐30), Aspergillus niger (AP‐12), and Candida rugosa (AY‐30). A better incorporation of stearic acid (SA), α‐linolenic acid (ALA), γ‐linolenic acid (GLA), arachidonic acid (AA), and docosapentaenoic acid (DPA) was achieved using lipase from Rhizomucor miehei. Lipase from Pseudomonas sp. catalyzed a better incorporation of linoleic acid (LA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) into triolein. Thus, Rhizomucor miehei and to a lesser extent Pseudomonas sp. might be considered as providing the most effective enzymes for acidolysis of triolein with selected LCFA. In general, incorporation of LCFA into triolein (tri C18:1) may be affected by chain length, number of double bonds, and the location and geometry of the double bonds as well as reaction conditions and reactivity and specificity of lipases used. As the ratio of the number of moles of a mixture of equimole quantities of C18 FA to triolein changed from 1 to 3, incorporation of C18 FA into triolein increased accordingly with Rhizomucor miehei lipase. Similarly, incorporation of n‐3 FA into triolein increased when ALA, DPA, DHA, and EPA were used. The same trend was noticed for a mixture of n‐6 FA (LA + GLA + AA) and triolein.

Synthesis and characterization of core-shell particles containing a perfluoroacrylate copolymer rich in the shell

A simple synthetic method for preparing the core-shell latex particles containing fluorinated shell was presented. Polymerization was achieved by a low-sheer monomer-starved emulsion polymerization process, thus facilitating mobility and subsequent polymerization of perfluoroacrylate (FA) along with methyl methacrylate (MMA) and n-butyl acrylate (nBA) monomers. The structure and thermal behavior of the resulting perfluoroacrylate copolymer were investigated by FTIR, NMR, and DSC. Furthermore, PCS, TEM as well as SFM, were carried out to characterize the surface morphology of the particles. These studies illustrated that the incorporation of FA into MMA/nBA particle morphologies facilitated surface phase separation during coalescence, resulted in F-containing film-air interfaces. Thus, surface properties with a significant increase in the contact angles could be produced. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Diacylglycerol acyltransferases from Vernonia and Stokesia prefer substrates with vernolic acid

Genetic engineering of common oil crops for industrially valuable epoxy FA production by expressing epoxygenase genes alone had limited success. Identifying other key genes responsible for the selective incorporation of epoxy FA into seed oil in natural high accumulators appears to be an important next step. We investigated the substrate preferences of acyl CoA:diacylglycerol acyltransferases (DGAT) of two natural high accumulators of vernolic acid, Vernonia galamensis and Stokesia laevis, as compared with a common oilseed crop soybean. Developing seed microsomes were fed with either [14C]oleoyl CoA or [14C] vernoloyl CoA in combinations with no exogenous DAG or with 1,2-dioleoyl-sn-glycerol, 1-palmitoyl-2-vernoloyl-sn-glycerol, 1,2-divernoloyl-sn-glycerol, 1,2-dioleoyl-rac-glycerol, or 1,2-divernoloyl-rac-glycerol to determine their relative incorporation into TAG. The results showed that in using sn-1,2-DAG, the highest DGAT activity was from the substrate combination of vernoloyl CoA with 1,2-divernoloyl-sn-glycerol, and the lowest was from vernoloyl CoA or oleoyl CoA with 1,2-dioleoyl-sn-glycerol in both V. galamensis and S. laevis. Soybean DGAT was more active with oleoyl CoA than vernoloyl CoA, and more active with 1,2-dioleoyl-sn-glycerol when oleoyl CoA was fed. DGAT assays without exogenous DAG, or with exogenous sn-1,2-DAG fed individually or simultaneously showed consistent results. In combinations with either oleoyl CoA or vernoloyl CoA, DGAT had much higher activity with rac-1,2-DAG than with their corresponding sn-1,2-DAG, and the substrate selectivity was diminished when rac-1,2-DAG were used instead of sn-1,2-DAG. These studies suggest that DGAT action might be an important step for selective incorporation of vernolic acid into TAG in V. galamensis and S. laevis.

Selective incorporation of docosahexaenoic acid into lysobisphosphatidic acid in cultured THP‐1 macrophages

Lysobisphosphatidic acid (LBPA) is highly accumulated in specific domains of the late endosome and is involved in the biogenesis and function of this organelle. Little is known about the biosynthesis and metabolism of this lipid. We examined its FA composition and the incorporation of exogenous FA into LBPA in the human monocytic leukemia cell line THP-1. The LBPA FA composition in THP-1 cells exhibits an elevated amount of oleic acid (18:1n-9) and enrichment of PUFA, especially DHA (22:6n-3). DHA supplemented to the medium was efficiently incorporated into LBPA. In contrast, arachidonic acid (20:4n-6) was hardly esterified to LBPA under the same experimental conditions. The turnover of DHA in LBPA was similar to that in other phospholipids. Specific incorporation of DHA into LBPA was also observed in baby hamster kidney fibroblasts, although LBPA in these cells contains very low endogenous levels of DHA in normal growth conditions. Our resuIts, together with published observations, suggest that the specific incorporation of DHA into LBPA is a common phenomenon in mammalian cells. The physiological significance of DHA-enriched LBPA is discussed.

Microtubular integrity differentially modifies the saturated and unsaturated fatty acid metabolism in cultured hep G2 human hepatoma cells

The influence of cytoskeleton integrity on the metabolism of saturated and unsaturated FA was studied in surface cultures and cell suspensions of human Hep G2 hepatoma cells. We found that colchicine (COL), nocodazol, and vinblastin produced a significant inhibition in the incorporation of labeled saturated FA, whereas incorporation of the unsaturated FA remained unaltered. These microtubule-disrupting drugs also diminished Delta9-, Delta5-, and Delta6-desaturase capacities. The effects produced by COL were dose (0-50 microM) and time (0-300 min) dependent, and were antagonized by stabilizing agents (phalloidin and DMSO). Dihydrocytochalasin B (20 microM) was tested as a microfilament-disrupting drug and produced no changes in either the incorporation of [14C] FA or the desaturase conversion of the substrates. We hypothesized that the interactions between cytoskeleton and membrane proteins such as FA desaturases may explain the functional organization, facilitating both substrate channeling and regulation of unsaturated FA biosynthesis.

Solvent‐free enzymatic synthesis of structured lipids containing CLA from coconut oil and tricaprylin

AbstractLipase‐catalyzed acidolysis of different TAG with CLA was performed to produce structured lipids (SL) containing CLA. An immobilized lipase from Mucor miehei (Lipozyme IM, Novo Nordisk Inc., Franklinton, NC) was used as the biocatalyst in a solvent‐free system. Conconut oil and tricaprylin, which are sources of medium‐chain FA, were the starting substrates, and a mixture of FFA (MFFA) containing 73% CLA was the donor of the acyl groups. For each TAG, four different ratios of TAG/MFFA were blended to prepare about 500 g of mixture containing 10, 20, 30, and 40% CLA (w/w). Each blend was reacted with 5% lipase at 65°C for 48 h under nitrogen. Over the range of TAG/MFFA ratios examined, CLA was incorporated effectively by the enzyme. Lipozyme IM exhibited no special preference for any particular FA, since the incorporation of FA was proportional to their concentration in the system. FFA, PV, p‐anisidine value (p‐AV), iodine value (IV), and saponification number (SN) were evaluated for all the SL. FFA, PV, and p‐AV depended on the purification process and showed no significant deterioration of SL with respect to the original TAG, whereas IV and SN depended on the composition of the SL, mainly the CLA content.

Selectivity of fatty acid incorporation into acylglycerols in esterification reactions using Rhizomucor miehei and Burkholderia cepacia lipases

Fatty acid incorporation into discrete acylglycerol (AG) pools during esterification reactions with glycerol was analyzed for processes mediated by Rhizomucor miehei and Burkholderia cepacia lipases. Multicompetitive mixtures of saturated FA (C4–C18 even chain) and oleic acid (C18:1) were reacted with glycerol and the temporal incorporation of FA into mono-, di- and triacylglycerol pools (MAG, DAG, TAG) was quantified by relative selectivity constants and dimensionless fatty acid partitioning coefficients. Both analyses revealed a general fidelity of FA selectivity during FA incorporation into each AG pool for each lipase, and little evidence of preferential incorporation of C8–C18 FA into an individual AG pool was obtained. Exceptions were noted for C4–6 FA and C18:1 FA which became selectively diminished and enriched, respectively, in the DAG and TAG pools. The observation that FA selectivity may be generally conserved throughout the sequential steps of TAG assembly may simplify the design of processes designed to yield specifically structured TAG using these lipases.

Reaction selectivity of Burkholderia cepacia (PS‐30) lipase as influenced by monoacylation of sn‐glycerol

AbstractReaction selectivities were determined in multicompetitive reactions mediated by Burkholderia cepacia lipase (Amano PS‐30) at a water activity of 0.19 in hexane. Saturated FA (C4–C18 even chain) and oleic acid (C18∶1) were reacted with a single alcohol, glycerol, α‐or β‐MAG, containing C4, C10, C16, or C18∶1 individually as alcohol cosubstrate. Similar odrinal patterns of FA selectivity, with C8, C10, and C16 preferred over others, were generally observed for incorporation of FA into specific acylglycerol (AG) pools of the 24 specific cases evaluated. The three exceptions were enrichment of C14 and C18 in the MAG pool with α‐C16‐MAG, substrate, and a general suppression of &gt;C8 incorporation into the TAG pool for reactions with α‐C10‐ and α‐C16‐MAG. PS‐30 lipase selectivity toward MAG was in descending order: α/β‐C4‐MAG&gt;β‐C10‐MAG&gt;β‐C16‐MAG&gt;α/β‐C18∶1‐MAG&gt;α‐C10‐MAG&gt;α‐C16‐MAG. Selectivity in channeling CX of the original CX‐MAG substrates into higher AG species was in descending order: α‐C10‐MAG∼α‐C16‐MAG&gt;α‐C18∶1‐MAG&gt;β‐C10‐MAG∼β‐C16‐MAG∼β‐C18∶1‐MAG &gt;α/β‐C4‐MAG. Generally, MAG were better acyl donors than FA for esterification reactions leading to DAG formation. These observations are relevant to the design of biocatalytic processes intended to yield specifically structured TAG.

Plackett‐burman design for determining the preference of Rhizomucor miehei lipase for FA in acidolysis reactions with coconut oil

AbstractThe preference of lipase (EC 3.1.1.3) from Rhizomucor miehei in the incorporation of 11 FA, ranging from C10∶0 to C22∶6, into coconut oil TAG during acidolysis was studied by applying the Plackett‐Burman experimental design. Enzymatic acidolysis reactions were carried out in hexane at 37°C for 48 h with coconut oil (0.1 M) and a mixture of 11 FA at a TAG to FA molar ratio of 1∶1. Lipase was used at the 5 wt% level. The incorporation of FA into coconut oil TAG was determined by GC. The lipase showed preference for long‐chain saturated FA for incorporation into coconut oil TAG. The FA with 18 carbon atoms showed a high incorporation rate (18∶1&gt;18∶1&gt;18∶3). The lipase showed the least preference for the incorporation of 12∶0, which occurs in maximal concentration (46%), whereas the most preferred FA, 18∶0, occurs at a very low concentration (&lt;2%) in coconut oil. The overall preference of lipase for the incorporation of different FA into coconut oil TAG was 18∶0&gt;18∶2, 22∶0&gt;18∶1, 18∶3, 14∶0, 20∶4, 22∶6&gt;16∶0&gt;12∶0≫10∶0.