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Isobutanol production by a recombinant biocatalyst Shimwellia blattae (p424IbPSO): Study of the operational conditions

Acedos, Miguel G., Ramon, Alberto, de la Morena, Susana, Santos, Victoria E., Garcia-Ochoa, Felix
Biochemical engineering journal 2018 v.133 pp. 21-27
air, biocatalysts, bioprocessing, bottles, glucose, oxygen, pH, yeast extract
The potential to produce high isobutanol concentrations from glucose with a new genetically modified microorganism, Shimwellia blattae (p424IbPSO), has been studied. The influences of several operating conditions (media composition, oxygen availability and pH) have been studied. Yeast extract concentration can be reduced 3.3 times from the more usual concentration, reducing the cost of the bioprocess, but obtaining no change in isobutanol yield: 0.173 gIb gGc−1. The influence of the oxygen availability on isobutanol production has also been considered. The use of higher air proportion into sealed bottles led to the best results in isobutanol concentration and productivity: 6 g L−1 and 0.19 g L−1 h−1, respectively. The study of the pH strategy shows that the best one is to begin at an initial pH value of 6.8, to let the pH fall freely to a value of 6.0 and then to control the pH at this value, obtaining about 11 g L−1 of isobutanol titer and about 0.286 gIb gGc−1 of yield.