https://www.cell.com/trends/biotechnology/pdf/S0167-7799(00)01457-8.pdf

Bioencapsulation within synthetic polymers (Part 1): sol–gel encapsulated biologicals

Properties and applications of proteins encapsulated within sol–gel derived materials

Novel products produced from seed oil materials (TAG, phospholipids, and minor components such as tocopherols, sterols, stanols, and fatty acyl esters of the latter two) by enzyme-mediated purification or chemical modification are reviewed. The primary focus is on “value-added products” of current and potential use (particularly in the food, cosmetics, and pharmaceutical industries) that require the selectivity of enzymes and mild operating conditions, the latter being beneficial for polyunsaturated and oxygenated acyl groups. The paper briefly reviews the biochemistry of enzymes in lipid modification (lipases, phospholipases, and lipoxygenases) and discusses and assesses the current and future applications, current state of the art, and areas for future research for the following enzyme-mediated processes: isolation of polyunsaturated and oxygenated FFA; formation of structured TAG as nutraceuticals; formation of MAG, saccharide-FA esters, and other polyhydric alcohol ester as emulsifiers and surfactants; isolation and/or modification of tocopherols and sterols as antioxidants; formation of hydroperoxides as chemical intermediates; and modification of phospholipids for use in liposomes.

Enzyme-Catalyzed modification of oilseed materials to produce eco-friendly products

Chicken fat was temperature-fractionated either without or with solvent, and by supercritical carbon dioxide extraction to produce trlacylglycerol (TAG) fractions of varying monounsaturated fatty acid (MUFA) content. Solvent fractionation from acetone at low temperature (-38 and -18°C) was the most effective process for enriching the MUFA-containing TAG of chicken fat in the liquid fractions. Caprylic acid was incorporated into the MUFA-enriched TAG fraction in lipase-catalyzed acidolysis reactions to produce structured lipids (SLs). Immobilization of the lipase within sol-gel phyllosilicate matrices allowed for the reusability of both lipases.

Fractionation of Chicken fat triacylglycerols : Synthesis of structured lipids with immobilized lipases

Lipoxygenase in pea roots subjected to biotic stress

Lipoxygenase (LOX) is an enzyme that regioselectively introduces the hydroperoxide functionality into polyunsaturated fatty acids, such as linoleic acid (LA) Hydroperoxide derivatives of polyunsaturated fatty acids are of interest because they can serve as important intermediates in the synthesis of chemical and pharmaceutical compounds In this study, LOX was immobilized in dispersed phyllosilicate layers that were cross-linked with silicate polymers formed by the hydrolysis of tetramethyl orthosilicates The effects of substrate concentration, reaction temperature and solvent participation were studied on the oxidation of LA by LOX The temperature optimum for the oxidation of LA by immobilized LOX was 25 degrees C and values of Km and Vmax for this reaction were 17 mM and 0023 micromol/min respectively Enzymic activity was stimulated by the addition of 10% (v/v) iso-octane to the reaction mixture The immobilized LOX preparation showed a degree of substrate preference that demonstrated that 1,3-dilinolein was a better substrate than LA in the oxidation reaction, followed in order by 1-monolinolein, methyl oleate and trilinolein In general, LOX immobilized in cross-linked phyllosilicates retained the physical and chemical characteristics of free LOX

Characterization of soybean lipoxygenase immobilized in cross- linked phyllosilicates

The continuous oxygenation of linoleic acid (LA) by immobilized lipoxygenase (LOX) was studied. Enzymatic oxidation was carried out in a recirculating packed column reactor using immobilized LOX as the stationary phase and LA as the substrate. The column, when packed with LOX immobilized in either a calcium alginate sol-gel matrix or a phyllosilicate sol-gel matrix, is equivalent to five continuous stirred tank reactors (CSTRs). The reactor cascade was calculated from the residence-time distribution for the reactor. Based on mass-balance calculations, a set of mathematical equations for predicting the concentration of oxygenated product generated in each CSTR was calculated. Product formation in the packed column reactor was simulated and results calculated with the model were compared with the experimental results. The data indicated that product yield (hydroperoxyoctadecadienoic acid, HPOD) increased asymptotically with reaction time. Experimentally, when the bioreactor was packed with calcium alginate sol-gel-immobilized LOX, an initial linear increase in HPOD production with time was observed, but reached a steady state. For the bioreactor packed with phyllosilicate sol-gel-immobilized LOX, initial HPOD production increased more rapidly but reached a lower steady-state concentration. From these data, a simple computer simulation model was developed to determine the process kinetics of this reactor design.

Immobilized lipoxygenase in a packed-bed column bioreactor: continuous oxygenation of linoleic acid.

Experimental solubilities were determined for 31 solid nonelectrolyte organic compounds dissolved in tert-butyl acetate at 298.15 K. Results of the experimental measurements were combined with published mole fraction solubility data for two lipid-lowering medicinal compounds (lovastatin and simvastatin) in order to derive Abraham model expressions for solute transfer into the tert-butyl acetate mono-solvent. The derived correlations provided an accurate mathematical description of the observed experimental data. As part of the current study, previously published Abraham model solvent correlations for both ethyl acetate and butyl acetate were updated using much larger datasets that contained an additional 64 and 35 experimental data points, respectively. The mathematical correlations presented in the current study describe the observed solubility ratios of solutes dissolved in tert-butyl acetate, ethyl acetate, and butyl acetate to within an overall standard deviation of 0.15 log units or less.

/pdf/development-of-abraham-model-correlations-for-solute-3aleverj.pdf

Development of Abraham Model Correlations for Solute Transfer into the tert-Butyl Acetate Mono-Solvent and Updated Equations for Both Ethyl Acetate and Butyl Acetate

Development of Abraham Model Correlations for Describing Solute Transfer into Transcutol Based on Molar Solubility Ratios for Pharmaceutical and Other Organic Compounds

Lipoxygenase (LOX) is an enzyme that regioselectively introduces a hydroperoxide into polyunsaturated fatty acids (PUFA). We recently reported a procedure that immobilizes soybean LOX within an alginate sol-gel matrix. In this study, the kinetic profile of free LOX was compared with that of the sol-gel immobilized LOX. The temperature dependent activity profile of free LOX was optimal at 25C whereas immobilized LOX had optimal activity over the temperature range of 25-35C. Enzyme activity, measured in aqueous buffer, for both the free and immobilized LOX preparations had K m values of 2.5 and 1.40 mmoles/L, respectively, and V max values of 0.056 and 0.02 μmol/min, respectively. The relative rates of oxidation of linoleic acid and acylglycerols containing linoleoyl residues catalyzed by free and immobilized LOX also were determined. The results showed that both free and immobilized LOX favor linoleic acid as a substrate. Relative substrate preference for free LOX was linoleic acid >1-monolinolein >1,3-dilinolein >trilinolein, and for immobilized LOX was linoleic acid >l,3-dilinolein >1-monolinolein >trilinolein. In general, LOX immobilized in alginate silica sol-gel matrix retained the physical and chemical characteristics of free LOX.

Emily Wu

Papers

Characterization of soybean lipoxygenase immobilized in cross- linked phyllosilicates

Immobilized lipoxygenase in a packed-bed column bioreactor: continuous oxygenation of linoleic acid.

Development of Abraham Model Correlations for Solute Transfer into the tert-Butyl Acetate Mono-Solvent and Updated Equations for Both Ethyl Acetate and Butyl Acetate

Development of Abraham Model Correlations for Describing Solute Transfer into Transcutol Based on Molar Solubility Ratios for Pharmaceutical and Other Organic Compounds

Kinetic behavior of soybean lipoxygenase : A comparative study of the free enzyme and the enzyme immobilized in an alginate silica sol-gel matrix