ABSTRACT
The techniques available to implement specific changes in both eukaryotic and prokaryotic cells are quite powerful. Through classic mutation-selection and modern genetic engineering, it is possible to amplify or attenuate existing enzyme activity, add completely new activities, and modify the regulation of existing pathways. Mutation and selection constitute a method of manipulating the phenotype of a cell. Cells are exposed to a mutagenic environment and then placed in a selective medium in which only those cells that have a desired mutation can grow. The techniques used to analyze the biochemistry at the beginning of the metabolic engineering cycle are also applicable for assessing the effects of any attempted changes. Metabolic engineering is an evolving discipline that tries to take advantage of the advances that have been made in the genetic manipulation of cells. Metabolic engineering is best viewed as an iterative process, where attempted modifications are evaluated and the successful cell lines improved further.
