This thesis presents the mathematical modeling of two new Escherichia coli platforms with economical potential in the production of biofuels and other chemicals, namely glycerol fermentation and the use of a reversal of the ?-oxidation cycle. With the increase in prices of traditional fuels, alternative renewable energy sources are needed, and the efficient production of biofuels becomes imperative as transport energy. So far studies have focused on using glucose as feedstock for the production of ethanol. In contrast, glycerol has become abundant and inexpensive in recent years, and the reversal of the ?-oxidation cycle is highly efficient for the production of long-chain products. These two platforms were reported experimentally in recent years, and their mathematical modeling is presented by the first time in this thesis.