PMID- 33407735
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20210112
IS  - 1754-6834 (Print)
IS  - 1754-6834 (Electronic)
IS  - 1754-6834 (Linking)
VI  - 14
IP  - 1
DP  - 2021 Jan 6
TI  - Modulating redox metabolism to improve isobutanol production in Shimwellia 
      blattae.
PG  - 8
LID - 10.1186/s13068-020-01862-1 [doi]
LID - 8
AB  - 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.
FAU - Acedos, Miguel G
AU  - Acedos MG
AD  - Chemical and Materials Engineering Department, Chemical Sciences School, 
      Universidad Complutense de Madrid, 28040, Madrid, Spain.
FAU - de la Torre, Isabel
AU  - de la Torre I
AD  - Chemical and Materials Engineering Department, Chemical Sciences School, 
      Universidad Complutense de Madrid, 28040, Madrid, Spain.
FAU - Santos, Victoria E
AU  - Santos VE
AD  - Chemical and Materials Engineering Department, Chemical Sciences School, 
      Universidad Complutense de Madrid, 28040, Madrid, Spain.
FAU - Garcia-Ochoa, Felix
AU  - Garcia-Ochoa F
AD  - Chemical and Materials Engineering Department, Chemical Sciences School, 
      Universidad Complutense de Madrid, 28040, Madrid, Spain.
FAU - Garcia, Jose L
AU  - Garcia JL
AD  - Department of Microbial and Plant Biotechnology, Centro de Investigaciones 
      Biologicas, CSIC, 28040, Madrid, Spain.
FAU - Galan, Beatriz
AU  - Galan B
AUID- ORCID: 0000-0002-2596-6034
AD  - Department of Microbial and Plant Biotechnology, Centro de Investigaciones 
      Biologicas, CSIC, 28040, Madrid, Spain. bgalan@cib.csic.es.
LA  - eng
GR  - S2018/BAA-452/Comunidad de Madrid/
GR  - CTQ2017- 84963-C2-1-R/mineco/
PT  - Journal Article
DEP - 20210106
PL  - England
TA  - Biotechnol Biofuels
JT  - Biotechnology for biofuels
JID - 101316935
PMC - PMC7789792
OTO - NOTNLM
OT  - Isobutanol
OT  - Redox balance
OT  - Shimwellia blattae
OT  - Synthetic pathway
COIS- The authors declare that they have no competing interests.
EDAT- 2021/01/08 06:00
MHDA- 2021/01/08 06:01
PMCR- 2021/01/06
CRDT- 2021/01/07 05:49
PHST- 2020/10/07 00:00 [received]
PHST- 2020/12/17 00:00 [accepted]
PHST- 2021/01/07 05:49 [entrez]
PHST- 2021/01/08 06:00 [pubmed]
PHST- 2021/01/08 06:01 [medline]
PHST- 2021/01/06 00:00 [pmc-release]
AID - 10.1186/s13068-020-01862-1 [pii]
AID - 1862 [pii]
AID - 10.1186/s13068-020-01862-1 [doi]
PST - epublish
SO  - Biotechnol Biofuels. 2021 Jan 6;14(1):8. doi: 10.1186/s13068-020-01862-1.