Ethanol production by E. coli KO11 and K. oxytoca P2 in MM using sucrose as carbon source is presented in Figs. 1B and 1D. Ethanol production, percent of maximum theoretical yield and volumetric productivity by both recombinants are listed in Table 1. Strain E. coli KO11 produced more ethanol than K. oxytoca P2 in MM, except at 12% sucrose. Ethanol production in medium with 2% sucrose was 75% of the maximum theoretical yield for KO11 and 55% for P2. Recombinant KO11 presented 41% (26.6 g ethanol/L) of the maximum theoretical yield while P2 presented 47% (30.9 g ethanol/L) at a 12% sucrose concentration (Figs. 1B and D and Table 1). The carbon source was probably the limiting factor for ethanol production at 2% to 4% sucrose while other nutrients were limiting at 8% to 12% sucrose. Ethanol production could probably increase at these higher sugar concentrations if the incubation time were increased, resulting in greater ethanol production efficiency. Recombinant P2 presented a lower yield but a higher volumetric productivity than KO11 (Table 1), converting sugar to ethanol more rapidly at all sugar concentrations tested.