Preface

PREFACE

Microbial catalysts are enzymes that contribute to many reactions and widely used in food and industrial products. Enzymes were discovered in the second half of the nineteenth century, since then have been extensively used in several industrial processes. Enzymes from microorganisms are extremely efficient and highly specific biocatalysts. An enzyme is a protein that catalyzes a specific reaction. The action of enzymes depends on their ability to bind the substrate at a domain of enzyme molecule called “active site”. Enzymes are more specific macromolecular biological catalysts that accelerate or catalyze chemical reactions. Some enzymes are not, however, reactive on their own, and often need cofactors. Chemically, enzymes like any catalyst, are not consumed in chemical reactions, nor do alter the equilibrium of a reaction. Enzyme activity can be affected by other molecules such as inhibitors and activators. Inhibitors are molecules that decrease enzyme activity, while activators are molecules that increase the enzyme activity. Many drugs and poisons are enzyme inhibitors. Activity of enzymes decrease markedly outside the optimal temperature and pH. Microbial enzymes (biocatalysts) are known to play a crucial role as metabolic catalysts, leading to their use in various applications and industrial fields. With the advancement in biotechnology over last three decades, especially in the area of genetics and protein engineering, enzymes have found their way into many new industrial processes.

Over 500 industrial products are being made using enzymes. Microorganisms have served and continue to serve as one of the largest and useful sources of many enzymes. In biocatalytic processes, natural catalysts such as protein enzymes perform chemical transformations on organic compounds. Microbial catalysts are environmentally friendly, greatly cost-effective, and consume lower energy. There is an increasing demand to replace some traditional chemical processes with biotechnological processes involving microorganisms or their enzymes such as pectinases, xylanases, cellulases, mannanase, α-galactosidase, laccases and ligninases which not only provide an economically viable alternative but are also more environmentally friendly. Uses of microbial enzymes in foods, pharmaceuticals, textile, paper, leather, and other industries are numerous and increased rapidly. Supplementary enzymes are added to the dough to ensure high bread quality in the form of a uniform crumb structure and better volume. Special enzymes can also increase the shelf life of bread by preserving its freshness longer. Enzymes have also contributed greatly to the development and improvement of modern household and industrial detergents, the largest application area for enzymes today. Moreover, one of the prime roles of enzymes is to improve the quality of leather.

Over the past century, there has been a tremendous increase in awareness of the effects of pollution. Enzymes can minimize the impact of pollution and waste on the environment. Replacement of some traditional chemical processes with biotechnological processes involving microorganisms is an advantage. All types of living organisms, where metabolic reactions occur, produce enzymes. A wide range of sources is used for production of commercial enzymes. Out of the total enzymes being used industrially, over half are extracted from fungi and yeast, one third are obtained from bacterial systems, and the remaining from animal (8%) and plant (4%) sources. Microorganisms are generally preferred than plant and animal as sources of industrial enzymes due to their low production costs, the enzyme content is more predictable and controllable, and more so because of the availability of raw materials with constant composition for their cultivation.

The current book consists of five different sections on Microbial Catalyst with topics include: Applied Microbiology, Industrial Microbiology, Agricultural Microbiology, Food Microbiology, and Structural Microbiology. All the sections discuss microbial catalysts with respect to the enzymes, their function, and benefits in general and to biotechnology as a subject of which ENZYMOLOGY is an integral part. Through this book we wish to bridge the gap between various literature that exists on enzymes, which is either too high on the caliber of written technical language or too low to be of scientific interest. Therefore, experts across the globe were invited to contribute in this comprehensive collection making it unique to be understandable, lucid, easy to increase our understanding of ENZYMOLOGY.

Collection of articles included in this book can be a useful material for Research Students, Post Graduate Students, Lecturers, Professors, and Academicians related to Microbiology, Biotechnology, Biochemistry, Environmental Sciences, Fermentation Technology, Health Professionals, Agricultural Sciences, Applied Microbiologists and many more alike.