(191ai) Analysis and Design of Kinetic Controls of Fatty Acid Synthesis

Microbial systems offer a promising means of producing fuels and chemicals from renewable feedstocks. Enzymes that evolved to control cellular growth and maintenance can be repurposed—or re-engineered—to convert metabolic intermediates into a wide range of useful oleochemicals (e.g., fatty acids, alkanes, alcohols, alkyl esters, and methyl ketones). To date, most approaches to synthesize these products have used genetic adjustments (i.e., enhanced or attenuated expression of native and non-native genes) to make additive or subtractive changes to the composition of the fatty acid pathway—often without consideration for the kinetics of the pathway. These approaches have enabled the production of useful classes of chemicals, but have proven limited in their ability to exert tight control over product profiles. In this talk, we will introduce a detailed kinetic model of type II fatty acid synthesis, and we will show how this model can facilitate metabolic engineering of fatty acid production in microbial systems. The results of our analysis explain unexpected observations from experimental studies of fatty acid synthesis (e.g., inhibition of fatty acid production by high concentrations of acyl carrier protein [ACP] and fatty acid biosynthesis [Fab] enzymes), provide an analytical framework for identifying kinetically coupled biocatalytic steps, and reveal new strategies for pairing coordinated genetic adjustments with protein engineering to tune fatty acid profiles in Escherichia coli.