The experimental observations for lactate yields and biomass yields during 60 days of adaptive evolution are also shown.
When 0.1% (w/v) yeast extract was added in the M9/RAC medium, cellulose digestibility and lactate yield were enhanced to 92% and 63% of the theoretical maximum, respectively.
A similar trend was observed with the lactate yield for Cases A and D. Overall, the CSTR appeared to be an inappropriate system with respect to achieving higher SCR and QH2.
At the highest tested levels of glucose and fructose (75 g/l each), the transformant strain experienced a 4-fold increase in PFK activity and a 2.3-fold increase in the glycolytic flux while the biomass yield reached 7 g/l (1.6 g/l in the parental strain), the mannitol yield was 56 g/l (10 g/l in the parental strain) and the lactate yield was 21 g/l (3.5 g/l in the parental strain).
The lactate yield from glucose was 0.158, −0.184, and −0.114 (mmol/mmol) for FB-L, FB-H, and FB-N, respectively.
The lactic acid yield in ammonium lactate decomposition and the subsequent ethyl lactate yield were also highly dependent on solvent ratio to ammonium lactate, temperature and pressure in ammonium lactate decomposition reaction.
Finally, continuous and resting cells culture experiments were performed and confirmed a higher lactate yield in non-growing than in growing conditions.
However, only the nonreactive phosphate-type solvent such as triethyl phosphate and tributyl phosphate showed a notable ethyl lactate yield in the subsequent esterification reaction compared with dimethyl sulfoxide and N-methyl pyrolidine.
No significant differences in lactate yield were observed among the other cultures (Case F, G, H, and I).
Deletion of both pforA and pfl resulted in a strain that required acetate and formate for growth and produced lactate as the primary fermentation product, achieving 88%% theoretical lactate yield.
