The ability to predict the behavior of fermentation systems enhances the possibility of optimizing their performance. Mathematical equations of model systems represent a tool for this and the most recent advances in computer hardware and software have made the approach more effective than previous simplistic attempts. The current knowledge of biochemical microbial pathways and the experience in optimization of chemical reactors combined with extremely powerful and accessible computers, loaded with easy to use software and mathematical routines, are changing the way processes are being developed and operated. This book has been written for all those who work with microbial cultures, providing a useful, quick and contemporary re-education for practitioners and students alike, breaking through interdisciplinary barriers. Biologists, engineers and biochemists will benefit from the methods of microbial process description and optimization based on mathematical equations.