Resting cells isobutanol production by <i>Shimwellia blattae</i> (p424IbPSO): Influence of growth culture conditions

Acedos, Miguel G.; Santos, Victoria E.; Garcı́a-Ochoa, Félix

doi:10.1002/btpr.2705

Cited by 9 publications

(11 citation statements)

References 51 publications

(104 reference statements)

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“…About 1.21 g Ib g x −1 were produced by C. glutamicum Iso7 and 1.21 g Ib g x −1 were obtained with C. glutamicum IBU8 . In a previous work, several experiments using resting cells under oxygen deprivation conditions were conducted obtaining 2.86 g Ib g x −1 . In this case, firstly an aerobic growth stage was carried out and then, in a second stage, isobutanol was produced by using resting cells (without adding any nitrogen source) under oxygen deprivation conditions.…”

Section: Introductionmentioning

confidence: 99%

Carbon flux distribution in the metabolism of Shimwellia blattae (p424IbPSO) for isobutanol production from glucose as function of oxygen availability

Acedos

Yustos

Santos

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND: The carbon flux distribution in Shimwellia blattae (p424IbPSO) cultures when glucose is employed as carbon source is studied in a stirred tank bioreactor changing the oxygen availability. The strain has been constructed to produce isobutanol combining the branched-chain amino acids pathway and Ehrlich pathway. The information of many similar genetic modified strains for this bioprocess in the literature presents significant discrepancies on the oxygen influence. RESULTS:The study carried out in this work pointed out the presence of other metabolites formed under aerobic conditions, such as isobutyric acid, 2,3-butanedione, acetoin, 2,3-butanediol and 3-oxo-1-buten-2-yl ether, not previously reported in the literature on the production of isobutanol with S. blattae (p424IbPSO) strain. CONCLUSION: In this work the routes or the chemical reactions involved in the bioprocess as a function of the availability of oxygen are elucidated. Anaerobic conditions are the best for isobutanol production from glucose employing this strain; around 12 g L −1 of isobutanol are obtained under these conditions. Aerobic conditions are not adequate to produce isobutanol, although the need for oxygen, at least for growth, is also demonstrated. Experimental procedure and set-upExperiments were carried out in a stirred tank bioreactor (STBR), BIOSTAT B-PLIS (Sartorius AG, Göttingen, Germany). The above described culture medium M9-2x was employed in all runs.The initial temperature of culture was 37 ∘ C, but after 2 h of growth the temperature was changed to 30 ∘ C and 1 mmol L -1 Isopropyl--D-1-thiogalactopyranoside (IPTG) was added to induce the expression of genes encoding the isobutanol synthetic pathway. The initial pH was fixed at 6.8, decreasing with time during growth; when pH reached a value of 6.0, it was controlled by the addition of 2 mol L -1 NaOH. 39 The airflow rate was set at 1 L L −1 min −1 from the beginning of the run and the stirrer speed was varied from 150 to 600 rpm in the different runs performed in aerobic conditions in order to change the oxygen transfer rate in J Chem Technol Biotechnol 2019; 94: 850-858 Analysis by GC-mass spectroscopyThis analysis was performed to determine the structures of the new compounds present in the S2 sample in comparison with the S1 sample. All the peaks appearing in the GC-MS chromatograms for both samples, S1 and S2, were identified. Table 3 gives the J Chem Technol Biotechnol 2019; 94: 850-858

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Section: Introductionmentioning

confidence: 99%

Carbon flux distribution in the metabolism of Shimwellia blattae (p424IbPSO) for isobutanol production from glucose as function of oxygen availability

Acedos

Yustos

Santos

et al. 2018

J of Chemical Tech & Biotech

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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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“…For reuse of cells plus CPS, the almost constant cell content indicated that during this process, the cells entered a resting state (Fig. 3) due to the depletion of other nutrients such as nitrogen sources (Acedos et al 2018). Limiting the supply of nitrogen sources was a common method of making resting cells (Wang et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Continuous degradation of phenanthrene in cloud point system by reuse of Sphingomonas polyaromaticivorans cells

et al. 2019

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Extractive biodegradation of phenanthrene by Sphingomonas polyaromaticivorans was previously carried out in cloud point system (CPS). In this study, we explored the possibility of further increasing the efficiency of the culture by repeatedly reusing cells and the system for biodegradation. Three different recycling strategies were adopted. In reuse of cells plus CPS, cells were reused for 3 times while maintaining high degradation rates (> 90%). Thereafter, the accumulation of metabolites in the dilute phase resulted in a decrease in cell viability. This inhibition was avoided in recycling the cells plus coacervate phase by replacing the dilute phase with fresh Medium. However, due to the slow adaptation of the cells to the new degradation environment and the reduction in the volume of the coacervate phase, the cells were only reused twice and their activity decreased. However, the same long degradation cycle (5 days) as the reuse of cells plus coacervate phase reduced the overall degradation efficiency of phenanthrene. Finally, a combined strategy of 3 times of cells plus CPS reuse and individual cells reuse once was employed and run for two cycles. 3 rounds of reuse of cells plus CPS improved cells utilization and phenanthrene degradation efficiency. Then, the subsequent round of reuse of cells alone relieved the effect of increasing metabolites on cell viability. This study provides a potential application for reusing cells to continuously degrade phenanthrene in soil and water in CPS.Electronic supplementary materialThe online version of this article (10.1186/s13568-019-0736-2) contains supplementary material, which is available to authorized users.

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Resting cells isobutanol production by Shimwellia blattae (p424IbPSO): Influence of growth culture conditions

Cited by 9 publications

References 51 publications

Carbon flux distribution in the metabolism of Shimwellia blattae (p424IbPSO) for isobutanol production from glucose as function of oxygen availability

Carbon flux distribution in the metabolism of Shimwellia blattae (p424IbPSO) for isobutanol production from glucose as function of oxygen availability

Modulating redox metabolism to improve isobutanol production in Shimwellia blattae

Continuous degradation of phenanthrene in cloud point system by reuse of Sphingomonas polyaromaticivorans cells

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