Book excerpt: We are all aware of opportunities created by advances in molecular biology. Living cells and their components can be used to produce a large number of useful compounds such as therapeutics and other products. But to obtain significant benefits as a commercial operation, molecular biology needs the support of biochemical engineering. The vital area of biotechnology that is concerned with practical application of biological agents (whole cell systems and biocatalysts) and the methodologies and processes associated with it on an industrial scale is biochemical engineering. Biochemical engineering is applicable in different areas of biotechnology such as biochemical reactions, enzyme technology, environmental biotechnology, microbial manipulations, bioseparation technology, plant and animal cell cultures, and food technology. It consists of the development of new process technology, designing bioreactors, developing efficient, and economically feasible extraction and purification procedures (downstream processing). Chapter 1 and 2 discuss about the basic concept of biotechnology and biochemical engineering. Chapter 3 tells about the concept of enzyme kinetics, their evolution and use in biochemical engineering. Chapter 4 and 5 describe immobilized enzyme and industrial applications of enzymes. Chapter 6 depicts about industrial microbiology. This chapter discuss different concepts about fermentation process, cell products and other modified compounds. Chapter 7 tells about different types of cell cultivations in microbial, animal, and plant. Chapter 8 discuss about the fermentation proce4ss and its control. Chapter 9 and 10 describe cell kinetics and fermenter design and also how the cell grows. Chapter 11 discuss about the bioreactor design. Chapter 12 depicts the downstream processing, centrifugration, sedimentation and other technology. Chapter 13 tells about the sterilization.