Strain Mgly13 produced glycolate with 0.385 g/g-glucose yield (45.2% of the theoretical yield).
The highest ethanol yield (37%% of the theoretical yield) was obtained with a dissolved oxygen (DO) of 20%%.
The maximum ethanol yield (99% of the theoretical yield, based on the available C6 sugars) was obtained with a mixture of SPWS containing 2.5% water-insoluble solids (WIS) and PWM containing 2.5% WIS, resulting in an ethanol concentration of 56.5 g/L.
Consequently, 1.198 g/g of sodium gluconate yield, 99% of the theoretical value, was achieved with the optimized seed culture, and this value proved to be the highest to be reported in the literature.
The best ethanol yield (48% of the theoretical) was achieved using an initial sugar mixture concentration of 4.5%.
In a study by España-Gamboa et al. the COD removal was found to be 69% and the methane yield 75% of the theoretical for vinasse treatment [ 50].
Furthermore, a higher ethanol yield (90% of the theoretical) in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions.
The metabolic adjustments carried out in the cell entail low organic acid production and an increase in the ethanol formation rate, as well as higher ethanol yield (90% of the theoretical) in glucose-mineral media when compared with previous engineered efficient strains, such as KO11 (70% of the theoretical yield).
Figure 5 shows the concentration profiles for total hexose sugars and the ethanol produced during fermentation, together with the final ethanol yields (percentage of the theoretical maximum stoichiometric yield based on all available hexose sugars).
In addition, the ethanol fermentation with this hydrolyzed solution by Saccharomyces cerevisiae achieved 50 g/L ethanol production, and this yield reached 90% of the theoretical yield.
