Enzyme Mediated Stereoselective Synthesis

This book is a collection of studies focused on the exploitation of enzyme stereoselectivity for the synthesis of relevant chemicals, such as innovative materials, chiral building blocks, natural products, and flavor and fragrance compounds. Different catalytic approaches are reported. The first study describes a resolution-based process for the stereoselective synthesis of the enantiomeric forms of the flavor compound linaloyl oxide, whereas other enantiomeric enriched aroma compounds were obtained through a novel microbial approach based on solid-state fermentation. Two relevant works exploit the potential of the biocatalyzed reduction reactions. The first of these contributions describes the enantioselective synthesis of β-nitroalcohols by enzyme-mediated reduction of α-nitroketones, whereas a second contribution reports the preparation of chiral 1,4-diaryl-1,4-diols through ADH-catalyzed bioreduction of the corresponding diketones. Concerning enantioenriched alcohol derivatives, natural hydroxy fatty acids are prepared by means of the biocatalytic hydration reaction of natural fatty acids using the probiotic bacterium Lactobacillus rhamnosus as a whole-cell biocatalyst. Further studies describe the use of modified pullulan polysaccharide for lipase immobilization and the recent advances in synthetic applications of ω-transaminases for the production of chiral amines.

This book is a collection of studies focused on the exploitation of enzyme stereoselectivity for the synthesis of relevant chemicals, such as innovative materials, chiral building blocks, natural products, and flavor and fragrance compounds. Different catalytic approaches are reported. The first study describes a resolution-based process for the stereoselective synthesis of the enantiomeric forms of the flavor compound linaloyl oxide, whereas other enantiomeric enriched aroma compounds were obtained through a novel microbial approach based on solid-state fermentation. Two relevant works exploit the potential of the biocatalyzed reduction reactions. The first of these contributions describes the enantioselective synthesis of ?-nitroalcohols by enzyme-mediated reduction of ?-nitroketones, whereas a second contribution reports the preparation of chiral 1,4-diaryl-1,4-diols through ADH-catalyzed bioreduction of the corresponding diketones. Concerning enantioenriched alcohol derivatives, natural hydroxy fatty acids are prepared by means of the biocatalytic hydration reaction of natural fatty acids using the probiotic bacterium Lactobacillus rhamnosus as a whole-cell biocatalyst. Further studies describe the use of modified pullulan polysaccharide for lipase immobilization and the recent advances in synthetic applications of ?-transaminases for the production of chiral amines.

This book offers an explanation of the specific ways that biocatalysis outperforms chemical catalysis by: utilizing ambient temperature and atmospheric pressure to minimize problems of isomerization, racemization, and epimerization; employing microbial cells and enzymes that can be immobilized and reused over many cycles; and overexpressing enzymes for greater economy and efficiency.

Enzymes in Action is a timely survey of a modern development in organic chemistry. It is clear that bioreagents demand that organic chemists think in a different way. If they do so, they will open up new avenues of exciting, new chemistry that will permit problems to be solved in an elegant way. The first section covers the concepts necessary to understand enzymes in molecular operations. The second section covers heteroatom enzyme chemistry, with considerable attention being given to the use of enzymes in the detoxification of chemical warfare agents and their application in environmental problems. The final section highlights the strategic use of enzymes in organic chemistry. It is clear that the term `green chemistry' is appropriate, since enzyme mediated processes occur under mild, environmentally benign conditions, and enzymes enable chemists to perform new chemical operations that would otherwise be difficult to achieve at all.

Perfect for biochemists, synthetic and organic chemists, this book covers all important reactions, including C-C coupling reactions, oxidation reactions and many more. Divided into two parts, the first section on methodology presents new innovative methods for enzymatic catalysis optimization, including such new trends as medium engineering, directed evolution and computer-aided prediction of enantioselectivity. The second and main section deals with applications to synthesis, showing important reaction types and their applications. Only those reactions with very high selectivity are presented, allowing readers to improve their own reaction yields.

This book covers the most recent development of enzymatic organic synthesis, with particular focus on the use of isolated enzymes. It is organized into one introductory chapter dealing with the characteristics of enzymes as catalysts, and five chapters dealing with different types of chemical transformations. Methods for enzyme immobilization and stabilizaton, the use of enzymes in extreme environments, and the alteration of enzyme properties by chemical modification and site-directed mutagenesis for synthetic purposes are covered.

This ready reference presents environmentally friendly and stereoselective methods of modern biocatalysis. The experienced and renowned team of editors have gathered top international authors for this book. They cover such emerging topics as chemoenzymatic methods and multistep enzymatic reactions, while showing how these novel methods and concepts can be used for practical applications. Multidisciplinary topics, including directed evolution, dynamic kinetic resolution, and continuous-flow methodology are also discussed. From the contents: * Directed Evolution of Ligninolytic Oxidoreductases: from Functional Expression to Stabilization and Beyond * New Trends in the In Situ Enzymatic Recycling of NAD(P)(H) Cofactors * Monooxygenase-Catalyzed Redox Cascade Biotransformations * Biocatalytic Redox Cascades Involving w-Transaminases * Multi-Enzyme Systems and Cascade Reactions Involving Cytochrome P450 Monooxygenases * Chemo-Enzymatic Cascade Reactions for the Synthesis of Glycoconjugates * Synergies of Chemistry and Biochemistry for the Production of Beta-Amino Acids * Racemizable Acyl Donors for Enzymatic Dynamic Kinetic Resolution * Stereoselective Hydrolase-Catalyzed Processes in Continuous-Flow Mode * Perspectives on Multienzyme Process Technology * Nitrile Converting Enzymes Involved in Natural and Synthetic Cascade Reactions * Mining Genomes for Nitrilases * Key-Study on the Kinetic Aspects of the In-Situ NHase/AMase Cascade System of M. imperiale Resting Cells for Nitrile Bioconversion * Enzymatic Stereoselective Synthesis of Beta-Amino Acids * New Applications of Transketolase: Cascade Reactions for Assay Development * Aldolases as Catalyst for the Synthesis of Carbohydrates and Analogs * Enzymatic Generation of Sialoconjugate Diversity * Methyltransferases in Biocatalysis * Chemoenzymatic Multistep One-Pot Processes