Читать книгу Enzyme-Based Organic Synthesis - Cheanyeh Cheng - Страница 9

Preface

The first time I was introduced to the field of microbiology was during the year 1982–1987, when I studied in the United States in the Department of Chemical & Biochemical Engineering of the Graduate and Professional School of Rutgers University to pursue my PhD degree. I was surprised that bacteria can live in an environment without air and at a temperature much higher than room temperature as well as ferment glucose to acetic acid. This study ignited my interest in the research of microorganisms and enzymes. As soon as I finished my PhD study in 1987, I came back to my alma mater, Chung Yuan Christian University, and worked as an associate professor in the Department of Chemistry, the place where I obtained my BS degree in 1974. I decided to continue my PhD research work to study the enzymatic cellulose hydrolysis for producing glucose using raw materials such as waste paper, dead tree branch, or waste bamboo chopsticks and the enantioselective bioreduction of ketones catalyzed by whole yeast cells for producing chiral secondary alcohols. I also taught a course called bioorganic chemistry, which focuses on the chemo‐, stereo‐, and regioselective enzyme or whole microbial cell catalyzed organic synthesis.

Ten years ago, I received an invitation from Wiley to write this book. At that moment I did not realize it is a big challenge for me to write a comprehensive book concerning enzyme‐catalyzed organic synthesis using six classes of enzymes. With the kind of courage that “the newborn calf is not afraid of tigers,” I accepted this invitation and wrote a book writing proposal. Fortunately, my proposal was approved by reviewers and I immediately started writing this book. Then I found I cannot concentrate my mind on writing this book and it takes me a long time to finish a chapter due to my teaching loads, my research works, student and family affairs, and many other trivial things. In fact, I could put all my time and mind on writing this book only after my retirement from school three and half years ago. I really appreciate the tolerant heart of Wiley editor to allow me to finish this book in such a long time. I learned a lot from writing this book, which also opened a new vision for me in the field of microbes and enzyme‐catalyzed organic synthesis. I also deeply understood the meaning of the Chinese proverb “Live and Learn.” What I did and what knowledge I acquired in my 30 years of academic career is only a small part of the field, just like a drop in the ocean. However, I sincerely hope that through this book more people will be interested in the field of enzyme‐catalyzed organic synthesis.

Life originated from single‐cell microorganisms, and microorganisms that cannot be seen by the human eye have existed on Earth since prehistoric times. Enzymes catalyze diverse chemical reactions in microbial cells from time to time and silently participate in the progress of life. The life phenomena presented by the variety of chemistry involved in the microbial cells is like a solemn and brisk music suite of life. No one would have expected that the relationship between enzymes and the tiny universe of microorganisms is so close and inseparable. Microorganisms are also taken as a cell factory by scientists due to their ability to produce various kinds of useful chemicals for human. However, as a result of the division of labor in science today, chemists, biochemists, biologists, biomedical scientists, biochemical engineers, etc., each use their own specialized scientific expertise to explore this life community, which has led to the difficulty in communication and the inefficient integration among different academic disciplines. Therefore, one of the goals of this book is to enable researchers from different disciplines to communicate and gain consensus to achieve integration.

The difference between enzyme‐based organic synthesis and traditional organic synthesis is that it uses a highly selective biocatalyst (enzyme), and the enzyme selectivity includes reaction substrate specificity, stereospecificity, and regiospecificity. The selectivity of enzyme also makes the enzyme‐based organic synthesis, particularly the asymmetric synthesis, more easy, convenient, and efficient to produce specialty chemicals. Because the enzyme‐based reaction is usually performed in aqueous solution under mild conditions and in many cases using sustainable renewable substrates, which demonstrates environmentally friendly, enzyme‐based organic synthesis fulfils the requirements of green chemistry. The development of enzymatic biotransformation or microbial fermentation has been over 50 years and has been implemented in numerous industrial applications. The recent advances in enzyme technology, such as protein engineering, site‐specific evolution, metabolic engineering, and enzyme immobilization, have made enzyme‐based organic synthesis more and more competitive with organic synthesis derived from fossil fuels.

This book contains eight chapters. Chapter 1 is an introduction to enzyme, coenzyme, enzyme specificity, and the green chemistry. Chapter 2 is about organic syntheses and their applications using class I oxidoreductases. Chapter 3 focuses on the transamination, glycosyl‐transfer, phosphorylation, and acetyl‐group transfer reactions using class II transferases and their applications. Chapter 4 is about class III hydrolases‐based organic syntheses including hydrolysis reactions of ester bond, amide bond, phosphate esters, epoxides, hydantoins, glycosidic bonds with natural polysaccharides, and their applications. Chapter 5 contains organic syntheses and applications using class IV lyases and concentrates on carbon‐carbon bond formation, carbon‐oxygen bond formation, carbon‐nitrogen bond formation, carbon‐sulfur bond formation, and carbon‐halide bond formation. Chapter 6 describes organic syntheses using class V isomerases including racemases and epimerases, cis–trans isomerase, intramolecular oxidoreductases, intramolecular transferases, intramolecular lyases, and their applications. Chapter 7 presents class VI ligases‐based organic syntheses and their applications focusing on carbon‐oxygen bond formation, carbon‐sulfur bond formation, carbon‐nitrogen bond formation, and carbon‐carbon bond formation reactions. The final Chapter 8 shows two major techniques that could assist the advancements of enzyme‐based organic syntheses in the future: one is the combinatorial chemistry and the other is artificial intelligence.

The level of contents of this book is medium to high suitable for readers having some basic knowledge of chemistry, organic chemistry, biochemistry, biology, microbiology, and chemical engineering. This book would be a very good reference book for academic researchers and industrial experts working on research and development. This book could also be used as a textbook for one semester course in senior class or graduate school class. Finally, I hope that this book will be able to “throw a brick to attract jade” to elicit truly outstanding books by experts and scholars in this field.

Cheanyeh Cheng

Chungli, January 2021