Effects of fluid-dynamic conditions in Shimwellia blattae (p424IbPSO) cultures in stirred tank bioreactors: Hydrodynamic stress and change of metabolic routes by oxygen availability

Acedos, Miguel G.; Hermida, Andrea; Gómez, Eduardo Escalante; Santos, Victoria E.; Garcı́a-Ochoa, Félix

doi:10.1016/j.bej.2019.107238

Cited by 9 publications

(3 citation statements)

References 46 publications

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“…As expected, the production of succinic acid as a by-product is not affected by the modifications carried out in this work, because its synthesis does not depend of NADH/ NADPH balance. Moreover, we cannot discard that PntAB overproduction can lead to an increased resistance of S. blattae (p424IbPSO, pIZpntAB) to alcohols as described in other organisms [39,40], and although S. blattae is a robust strain [41,42] its growth is inhibited at concentrations of isobutanol above 8 g L −1 [22]. This fact can also explain the observed higher growth of S. blattae (p424IbPSO, pIZpntAB) ( Fig.…”

Section: Strainmentioning

confidence: 88%

Modulating redox metabolism to improve isobutanol production in Shimwellia blattae

Acedos

Torre

Santos

et al. 2021

Biotechnol Biofuels

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Background Isobutanol is a candidate to replace gasoline from fossil resources. This higher alcohol can be produced from sugars using genetically modified microorganisms. Shimwellia blattae (p424IbPSO) is a robust strain resistant to high concentration of isobutanol that can achieve a high production rate of this alcohol. Nevertheless, this strain, like most strains developed for isobutanol production, has some limitations in its metabolic pathway. Isobutanol production under anaerobic conditions leads to a depletion of NADPH, which is necessary for two enzymes in the metabolic pathway. In this work, two independent approaches have been studied to mitigate the co-substrates imbalance: (i) using a NADH-dependent alcohol dehydrogenase to reduce the NADPH dependence of the pathway and (ii) using a transhydrogenase to increase NADPH level. Results The addition of the NADH-dependent alcohol dehydrogenase from Lactococcus lactis (AdhA) to S. blattae (p424IbPSO) resulted in a 19.3% higher isobutanol production. The recombinant strain S. blattae (p424IbPSO, pIZpntAB) harboring the PntAB transhydrogenase produced 39.0% more isobutanol than the original strain, reaching 5.98 g L−1 of isobutanol. In both strains, we observed a significant decrease in the yields of by-products such as lactic acid or ethanol. Conclusions The isobutanol biosynthesis pathway in S. blattae (p424IbPSO) uses the endogenous NADPH-dependent alcohol dehydrogenase YqhD to complete the pathway. The addition of NADH-dependent AdhA leads to a reduction in the consumption of NADPH that is a bottleneck of the pathway. The higher consumption of NADH by AdhA reduces the availability of NADH required for the transformation of pyruvate into lactic acid and ethanol. On the other hand, the expression of PntAB from E. coli increases the availability of NADPH for IlvC and YqhD and at the same time reduces the availability of NADH and thus, the production of lactic acid and ethanol. In this work it is shown how the expression of AdhA and PntAB enzymes in Shimwellia blattae increases yield from 11.9% to 14.4% and 16.4%, respectively.

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Section: Strainmentioning

confidence: 88%

Modulating redox metabolism to improve isobutanol production in Shimwellia blattae

Acedos

Torre

Santos

et al. 2021

Biotechnol Biofuels

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“…K La is an important parameter for the design, operation, scale-up, and optimization of the reactor [ 16 ]. To evaluate K La in the presence of Mixed liquor volatile suspended solids (MLVSS) 3000, 6000 mg/L, a comparative experiment with tap water was conducted, and the amount of change in dissolved oxygen with time was measured.…”

Section: Methodsmentioning

confidence: 99%

Application of jetventurimixer for developing low-energy-demand and highly efficient aeration process of wastewater treatment

Choi¹,

Jeong²,

Lee³

2022

Heliyon

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“…However, none of the previously described kinetic models consider the oxygen availability. The importance of oxygen transfer rate in aerobic the bioprocess has already been pointed out in many works [16,[25][26][27][28]. Recently, several authors have put their effort on describing the influence of oxygen transfer rate on DHA production.…”

Section: Introductionmentioning

confidence: 93%

Kinetic Modeling of Dihydroxyacetone Production from Glycerol by Gluconobacter oxydans ATCC 621 Resting Cells: Effect of Fluid Dynamics Conditions

et al. 2020

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Dihydroxyacetone production from glycerol has been studied. Cultures of Gluconobacter oxydans ATCC 621, a promising microorganism that is able to convert glycerol into dihydroxyacetone, has been employed. In this work, the influence of oxygen transport rate and the fluid dynamic conditions have been studied working with resting cells cultures. Several experiments were carried out at two different scales: 250 mL Erlenmeyer flasks and a 2 L stirred tank bioreactor, varying the agitation speed. Product and substrate concentration were determined employing high-performance liquid chromatography. Additionally, oxygen concentration was measured in the runs carried out in stirred tank reactors. Taking into account the results obtained in these experiments, three different behaviors were observed, depending on the mass transfer and chemical reactions rates. For experiments with low stirring speed (below 200 rpm for shake flasks and 300 rpm for reactors), the oxygen transport rate is the controlling step, while at high stirring speed (over 300 rpm in shake flasks and 560 rpm in the bioreactor), the chemical reaction is controlling the overall process rate. In some runs conducted at medium agitation, a mix control was found. All the kinetic models were able to reproduce experimental data and fulfill thermodynamic and statistical criteria, highlighting the importance of the mass transfer rate upon this system.

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Effects of fluid-dynamic conditions in Shimwellia blattae (p424IbPSO) cultures in stirred tank bioreactors: Hydrodynamic stress and change of metabolic routes by oxygen availability

Cited by 9 publications

References 46 publications

Modulating redox metabolism to improve isobutanol production in Shimwellia blattae

Modulating redox metabolism to improve isobutanol production in Shimwellia blattae

Application of jetventurimixer for developing low-energy-demand and highly efficient aeration process of wastewater treatment

Kinetic Modeling of Dihydroxyacetone Production from Glycerol by Gluconobacter oxydans ATCC 621 Resting Cells: Effect of Fluid Dynamics Conditions

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