Specific nutritional requirements of microorganisms used in industrial fermentation processes are as complex and varied as the microorganisms in question. Not only are the types of microorganisms diverse (bacteria, molds and yeast, normally), but the species and strains become very specific as to their requirements

A common problem for a biochemical engineer is to be handed a microorganism and be told he has six months to design a plant to produce the new fermentation product. Although this seems to be a formidable task, with the proper approach this task can be reduced to a manageable level. There are many ways to approach the problem of optimization and design of a fermentation process

Fluid mixing is essential in fermentation processes. Usually the most critical steps in which mixers are used are in the aerobic fermentation process. However, mixers are also used in many auxiliary places in the fermentation process and there are places also for agitation in anaerobic fermentation steps

The engineer designing an ion exchange column operation usually will prefer to work with the simplest kinetic model and linear driving force approximations. The weakness ofthis approach is that any driving force law only regards the momentary exchange rate as a hnction of the solute concentration in the bulk solution and the average concentration in the particle, neglecting the effect of concentration profiles in the particle

Often in multiple-effect evaporators the concentration of the liquid being evaporated changes drastically from effect to effect, especially in the latter effects. In such cases, this phenomenon can be used to advantage by staging one or more of the latter effects. Staging is the operation of an effect by maintaining

Crystallization is one of the oldest methods known for recovering pure solids from a solution. The Chinese, for example, were using crystallization to recover common salt from water some 5000 years ago. The perfection and beauty of the crystal which fascinated the early tribes now leads to a product of high purity and attractive appearance

The drying operation is often the final step of a manufacturing process. Indirect drying will be discussed in this section; it is the process of removing liquid by conductive heat transfer. Sometimes drymg is apart ofthe manufacturing process itself, as in the case of seasoning oftimber or in paper making, but generally, the reasons for carrying out a drying operation are:

Common, everyday water is a major consideration in a pharmaceu￾tical plant. The final product or any of its intermediate materials can only be as contaminant-free as the water available at that stage. Water may be an ingredient or used principally to wash and rinse product contact components and equipment. Water is also used to humidiethe air, to generate clean steam for sterilization, to cool or heat, as a solvent, for drinking and sanitary uses, etc. To better control this critical media

“Evaporation is the removal of solvent as a vapor from a solution or slurry. The vapor may or may not be recovered, depending on its value. The end product may be a solid, but the transfer of heat in the evaporator must be to a solution or a suspension of the solid in liquid if the apparatus is not to be classed as a dryer. Evaporators are similar to stills or re-boilers of distillation

Cross-flow filtration (CFF) also known as tangential flow filtration is not of recent origin. It began with the development of reverse osmosis (RO) more than three decades ago. Industrial RO processes include desalting of sea water and brackish water, and recovery and purification of some fermentation products. The cross-flow membrane filtration technique was next applied to the concentration and fractionation ofmacromolecules commonly recognized