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Close to the edge: growth restrained by the NAD(P)H/ATP formation flux ratio

van Niel, Ed LU ; Bergdahl, Basti LU and Hahn-Hägerdal, Bärbel LU (2017) In Frontiers in Microbiology 8.
Abstract
Most fermentative microorganisms grow well-under anaerobic conditions managing a balanced redox and appropriate energy metabolism, but a few species do exist in which cells have to cope with inadequate energy recovery or capture and/or redox balancing. Two cases of these species, i.e., the metabolically engineered Saccharomyces cerevisiae enabling it to ferment xylose and Lactobacillus reuteri fermenting glucose via the phosphoketolase pathway, are here used to introduce a quantification parameter to capture what limits the growth rate of these microorganisms under anaerobic conditions. This dimensionless parameter, the cofactor formation flux ratio (RJ), is the ratio between the redox formation flux (JNADH+NADPH), and the energy carrier... (More)
Most fermentative microorganisms grow well-under anaerobic conditions managing a balanced redox and appropriate energy metabolism, but a few species do exist in which cells have to cope with inadequate energy recovery or capture and/or redox balancing. Two cases of these species, i.e., the metabolically engineered Saccharomyces cerevisiae enabling it to ferment xylose and Lactobacillus reuteri fermenting glucose via the phosphoketolase pathway, are here used to introduce a quantification parameter to capture what limits the growth rate of these microorganisms under anaerobic conditions. This dimensionless parameter, the cofactor formation flux ratio (RJ), is the ratio between the redox formation flux (JNADH+NADPH), and the energy carrier formation flux (JATP), which are mainly connected to the central carbon pathways. Data from metabolic flux analyses performed in previous and present studies were used to estimate the RJ-values. Even though both microorganisms possess different central pathways, a similar relationship between RJ and the specific growth rate (μ) was found. Furthermore, for both microorganisms external electron acceptors moderately reduced the RJ-value,
thereby raising the μ accordingly. Based on the emerging profile of this relationship an interpretation is presented suggesting that this quantitative analysis can be applied beyond the two microbial species experimentally investigated in the current study to provide data for future targeted strain development strategies. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
NADH, NADPH, ATP, Saccharomyce cerevisiae, Lactobacillus reuteri, redox imbalance, ATP formation flux, NAD(P)H formation flux
in
Frontiers in Microbiology
volume
8
pages
9 pages
publisher
Frontiers
external identifiers
  • scopus:85021226110
  • wos:000403873300001
ISSN
1664-302X
DOI
10.3389/fmicb.2017.01149
language
English
LU publication?
yes
id
a488b8ab-be58-41ef-aa3b-a7f3cd41eddf
date added to LUP
2017-06-22 11:28:51
date last changed
2017-09-22 03:00:02
@article{a488b8ab-be58-41ef-aa3b-a7f3cd41eddf,
  abstract     = {Most fermentative microorganisms grow well-under anaerobic conditions managing a balanced redox and appropriate energy metabolism, but a few species do exist in which cells have to cope with inadequate energy recovery or capture and/or redox balancing. Two cases of these species, i.e., the metabolically engineered Saccharomyces cerevisiae enabling it to ferment xylose and Lactobacillus reuteri fermenting glucose via the phosphoketolase pathway, are here used to introduce a quantification parameter to capture what limits the growth rate of these microorganisms under anaerobic conditions. This dimensionless parameter, the cofactor formation flux ratio (RJ), is the ratio between the redox formation flux (JNADH+NADPH), and the energy carrier formation flux (JATP), which are mainly connected to the central carbon pathways. Data from metabolic flux analyses performed in previous and present studies were used to estimate the RJ-values. Even though both microorganisms possess different central pathways, a similar relationship between RJ and the specific growth rate (μ) was found. Furthermore, for both microorganisms external electron acceptors moderately reduced the RJ-value,<br/>thereby raising the μ accordingly. Based on the emerging profile of this relationship an interpretation is presented suggesting that this quantitative analysis can be applied beyond the two microbial species experimentally investigated in the current study to provide data for future targeted strain development strategies.},
  articleno    = {1149},
  author       = {van Niel, Ed and Bergdahl, Basti and Hahn-Hägerdal, Bärbel},
  issn         = {1664-302X},
  keyword      = {NADH,NADPH,ATP,Saccharomyce cerevisiae,Lactobacillus reuteri,redox imbalance,ATP formation flux,NAD(P)H formation flux},
  language     = {eng},
  month        = {06},
  pages        = {9},
  publisher    = {Frontiers},
  series       = {Frontiers in Microbiology},
  title        = {Close to the edge: growth restrained by the NAD(P)H/ATP formation flux ratio},
  url          = {http://dx.doi.org/10.3389/fmicb.2017.01149},
  volume       = {8},
  year         = {2017},
}