Gene-expression tools for the metabolic engineering of bacteria

Recent advances in metabolic engineering have led to new methods for the synthesis of novel molecules, improved production of existing compounds and improved degradation of recalcitrant environmental contaminants. Increasing the flux through an existing pathway and introducing a new pathway into a host organism demand coordinated expression of the genes that encode the enzymes, tight control over gene expression and consistent expression in all cells. Although several gene-expression tools have been developed for the overproduction of proteins, they may not be ideal for pathway redirection. Metabolic engineering requires certain characteristics of gene-expression tools, and some new tools meet these needs.