Development of Improved Strains and Optimization of Fermentation Processes

Microbial strains overproducing commercially important metabolites are routinely obtained through mutagenesis and random screening and/or selection. Advances in recombinant DNA technology have made it possible for engineering improved microbial strains by specific addition or deletion of certain genes. The key to the genetic engineering approach, however, is the identification of genes controlling metabolite production. In recent years, innovative technologies have been developed to allow researchers to investigate the genetics and physiology of a microorganism on a global scale. Knowledge gained from these studies is beginning to modernize strain development processes. Fermentation processes must be constantly optimized in order to maximize the potential of each improved strain. This chapter reviews the various methods of developing improved strains and addresses the specific issues concerning each method. In addition, strategies commonly employed to optimize fermentation processes will be analyzed. Finally, new technologies and how they can help strain development and fermentation process optimization will be discussed.