3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization.

Industrial use of immobilized enzymes

Nanostructures for enzyme stabilization

Enzymatic biodiesel production has been investigated intensively, but is presently employed industrially only in a 20,000 tons/year pilot plant in China (Du et al. [2008] Appl Microbiol Technol 79(3):331-337). This review presents a critical analysis of the current status of research in this area and accentuates the main obstacles to the widespread use of enzymes for commercial biodiesel transesterification. Improved results for enzymatic catalysis are seen with respect to increased yield, reaction time and stability, but the performance and price of the enzymes need further advances for them to become attractive industrially for biodiesel production. Critical aspects such as mass transfer limitations, use of solvents and water activity are discussed together with process considerations and evaluation of possible reactor configurations, if industrial production with enzymes is to be carried out. Results of published studies on the productivity of enzymes are also presented and compared to the use of chemical catalysts.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/bit.22256

A review of the current state of biodiesel production using enzymatic transesterification

Different methods of preparing lipases for use in organic media are critically reviewed. Solid lipase preparations can be made by typical immobilisation methods such as adsorption, entrapment, covalent coupling or cross-linking. Immobilisation is especially attractive for lipases because, in addition to the normal benefits of enzyme immobilisation, it can also lead to a considerable increase in catalytic activity, probably caused by conformational changes in the lipase molecules. Activation can be achieved, for example, using hydrophobic support materials or surfactants during the immobilisation procedure. Surfactants can also be used to solubilise lipases in organic media via the formation of hydrophobic ion pairs, surfactant-coated lipase or reversed micelles. Lipase preparation methods are discussed with regard to potential lipase inactivation and activation effects, mass transfer limitations, lipase stability and other features important for applications. The practical applications of lipases in organic media reviewed include ester synthesis, modification of triacylglycerols and phospholipids, fatty acid enrichment, enantiomer resolution, biodiesel production and acylation of carbohydrates and bioactive compounds.

/pdf/immobilisation-and-application-of-lipases-in-organic-media-5fav701sop.pdf

Immobilisation and application of lipases in organic media.

Different enzyme requirements for the synthesis of biodiesel: Novozym 435 and Lipozyme TL IM.

A support for enzyme immobilization was prepared by functionalization of mesoporous silica with octyltriethoxysilane. The features of the surface enables the adsorption of lipase from Candida antarctica B via strong hydrophobic interactions, enhancing the stability of the adsorbed enzyme molecules. Derivatives with a high enzyme loading (200 mg protein/g of silica) can be obtained due to the high porosity and surface properties of the support while the immobilization occurs in a monolayer fashion. The lack of inactive enzyme aggregates, together with the high enzyme loading, are responsible for the high catalytic activity achieved by these species. Derivatives were prepared with different lipase loading, and the activities were tested and compared to the commercial derivative Novozym 435. The stability of the catalyst and hence its industrial applicability were tested by performing subsequent reaction cycles of acylation of ethanolamine with lauric acid in acetonitrile. Conversion was quantitative even after 15 reaction cycles.

Functionalization of mesoporous silica for lipase immobilization: Characterization of the support and the catalysts

Purification and characterization of two distinct lipases from Candida cylindracea.

Selective production of emulsifiers from glucose and fatty acids has been achieved using an immobilized Candida antarctica lipase. Optimization of process selectivity considers the solubilities of the sugar and its monoesters in acetone at different temperatures, the percentage of this organic solvent in the reaction mixture, and the reaction temperature. The solvent (acetone) is both easily eliminated and accepted by the European Community for use in the manufacture of foods and/or food additives. Different fatty acids with a longer length chain than that of caprylic acid may be employed. For saturated fatty acids longer than lauric acid, continuous precipitation of the monoester as it is formed at 40 degrees C permits nearly complete conversion (98%) of glucose to the monoester within 2-3 days. The procedure does not require total dissolution of the sugar, and precipitation of the monoester permits selective conversion of charges of glucose higher than 100 mg/mL solvent. A scaleup of the process under the optimum conditions gives high yields of 6-O-lauroyl glucose, which may be readily prepared on a gram scale. Copyright 1998 John Wiley & Sons, Inc.

Cristina Otero

Papers

Different enzyme requirements for the synthesis of biodiesel: Novozym 435 and Lipozyme TL IM.

Functionalization of mesoporous silica for lipase immobilization: Characterization of the support and the catalysts

Purification and characterization of two distinct lipases from Candida cylindracea.

Quantitative enzymatic production of 6-O-acylglucose esters

Effect of chemical modification of Novozym 435 on its performance in the alcoholysis of camelina oil