Synthesis of Acetoin and 2,3-Butanediol by Engineered Escherichia Coli

With a versatility of uses in the pharmaceutical, food and beverage, commodity chemical, and biofuels industries, acetoin and 2,3-butanediol are building block materials of particular interest. Although these are natural fermentation products of a variety of microorganisms, the prospects of productivity enhancement are limited by relatively poor characterization of such native strains. Accordingly, through metabolic engineering approaches we have explored the potential for production of acetoin and 2,3-butanediol in well-characterized Escherichia coli hosts. Within E. coli, we have explored both the reconstruction of the natural biosynthetic pathway of Lactococcus lactis, as well as the recombination of other foreign genetic elements which encode homologous enzymatic function in an effort to enhance product titers. Approaches to elevate the availability of both precursors and cofactors have also been explored and their impact on product formation is presented.