Polymer Synthesis and Modification by Enzymatic Catalysis Muttaqin 23 June 2009

History Overview Enzymatic reactions have been widely used since 1980s Two major directions of polymerization catalyst : Acids-Bases Transition metal Enzymatic polymerization

Motivation Synthesis and modification of polymers using enzymatic catalysis for better performance and environment

Outline Introduction Hydrolase Enzymes Enzymatic polymerization Modification of polymers Applications Disadvantages of the enzymatic method Conclusion References

Introduction : Characteristics of Enzymatic Synthesis Two important aspects on enzymatic reactions : 1. Key and Lock Theory (Fischer : 1894)

Introduction : Characteristic of Enzymatic Synthesis 2. Lowering the activation energy (Pauling) Reaction Profile Key Factor : Design and synthesis an artificial monomer

Introduction : Advantages of enzymatic polymerization Precise control of polymer structures (regioselectivity, chemoselectivity, stereochemistry) No need protection and deprotection Clean process, mild condition, environmental friendly Produce biodegradable polymers (many cases)

Introduction : Classification of Enzymes EnzymesExamples Enzymes Typical Polymers-1 Typical Polymers-2 1. Oxidoreductase Peroxidase Tyrosinase Glucose oxidase Polyphenols, polyanilines, Vynyl polymers Polysaccharides, polypeptides (protein) 2. Transferase Glycosyltransferase Acyltransferase Polysaccharides, cyclic olygosaccharides, polyester Polysaccharides, polypeptides (protein) 3. Hydrolase Glycosidase (Cellulase, chitinase, amylase, etc) Lipase Peptidase Polysaccharides, polyester, polyamides, polycarbonates, poly(amino acid)s Polysaccharides, polypeptides (protein) 4. Lyase Decarboxylase Adolase, Dehydrase polysaccharides 5. Isomerase Racemase Epimerase 6. Ligase Acyl CoA synthetase

Enzymatic polymerization : Hydrolase – Lipase Enzyme Lipase is an enzyme that catalyzes the hydrolysis of fatty acid ester Lipase can be used to catalyse polymerization reactions, such as Polyester The reaction of lipase-catalyzed polymerization can be done by ROP or Polycondensation

Enzymatic polymerization : Reaction Mechanism of ROP

The rate determining step is the EM formation

Enzymatic polymerization : Polyester via Polycondensation

Enzymatic Polymerization : Enantioselective and Chemoselective Enantioselective : - Prefer to produce one enantiomer to another Chemoselective : - Selective to a functional group

Modification of Polymer : By Enzymatic Catalysis Purpose Improve the polymer properties Produce polymer with environmental friendly Fulfill market demand

Modification of Polymer : Polysaccharides by lipase enzyme

Applications : Polysaccharides Biocompatible, biodegradable, and non- toxic Use : Biomedical purposes, such as for drug delivery. Paper industries, water treatment, and other industrial applications

Applications : Polyester Usefulness : Packaging, textile, resin, liquid crystal display, plastic display, etc

Disadvantages of the Enzymatic Method 1. Limitation of substrates 2. Availability and cost of enzymes 3. Reaction : ofen slower than chemical methods

Conclusion The enzymatic reaction takes place under mild condition and is excellent in controlling polymer structures The enzymatic reaction also reduces environmental problems However, this reaction is restricted by availability of substrates and enzymes

References 1. Macromolecule Engineering. Precise Synthesis, Material Properties, Application. Edited by K. Matyjaszewski, Y. Gnanou, and L. Leiber. Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 2. Physical chemistry for the life Sciences. P. Atkins, J. d. Paula. © 2006 W.H. Freeman and Company 41 Madison Avenue, New York. 3. Introduction to Polymer Science and Chemistry. M. Chandra. Copyright © 2006 by Taylor & Francis Group, LLC. CRC Press, New York

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