TABLE OF CONTENTS Microbial populations dominate the biosphere in terms of metabolic impact and numbers. Among the various types of microbes, prokaryotes are the most pervasive lifeform on the planet, often tolerating extremes in pH, temperature, salt concentration, etc. Metabolic diversity is greater among prokaryotes than all eukaryotes combined. Men have long been utilizing the bacterial and yeast and fungal population for the manufacturing of various chemicals, biochemicals, antibiotics, beverages, etc. Production of antibiotics, alcohols, vinegar, amino acids, vitamins, therapeutic antibodies, acetone and other solvents, and recombinant proteins is accomplished by the large-scale cultivation of microbial cells such as bacteria, algae, yeast, and fungus on industrial scale. In all these industrial applications the metabolic activities or the biochemical pathways are used for the production of specific chemicals with the consumption of the substrates or a carbon source such as sucrose. Here, the microbial culture acts as a factory, where the substrate is the raw material. It is converted into the product and secreted into the media. The product can be recovered from the media with a process called downstream processing. There is a limitation for a single cell to convert the raw material into products in a given period of time. It is possible to calculate the rate of product formation by a single cell under a specific metabolic condition, if we know the quantity of product formed over a period of time and the number of cells in the culture. If we want to produce a specific quantity of...
