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Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in Limosilactobacillus reuteri DSM 17938

Seshagiri Rao, Nikhil LU ; Ermann Lundberg, Ludwig ; Tomasson, Julia ; Tullberg, Cecilia LU ; Brink, Daniel P. LU ; Bai Palmkron, Shuai LU ; van Niel, Ed W. J. LU ; Håkansson, Sebastian LU and Carlquist, Magnus LU (2023) In Frontiers in Microbiology 14.
Abstract
The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 ml/min, with a growth rate of 0.74 ± 0.13 h-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for... (More)
The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 ml/min, with a growth rate of 0.74 ± 0.13 h-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8 ± 2.4 % vs 11.5 ± 4.3 %), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs 3.59 for N2 sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5’nucleotidase activity (370 U/L vs 240 U/L in N2 sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90 min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimisation of L. reuteri DSM 17938. (Less)
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; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Online flow cytometry, K Mean clustering, Fatty acid (FA), Bile and Acid Tolerance, 5' Nucleotidase, Limosilactobacillus reuteri DSM 17938, Oxygen, Freeze-drying (FD)
in
Frontiers in Microbiology
volume
14
article number
1152389
pages
13 pages
publisher
Frontiers Media S. A.
external identifiers
  • scopus:85159792351
  • pmid:37125176
ISSN
1664-302X
DOI
10.3389/fmicb.2023.1152389
language
English
LU publication?
yes
id
90cb197c-6ef9-4b5b-8f94-9e84db07e20c
date added to LUP
2023-03-22 19:56:24
date last changed
2024-01-05 00:13:54
@article{90cb197c-6ef9-4b5b-8f94-9e84db07e20c,
  abstract     = {{The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 ml/min, with a growth rate of 0.74 ± 0.13 h-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8 ± 2.4 % vs 11.5 ± 4.3 %), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs 3.59 for N2 sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5’nucleotidase activity (370 U/L vs 240 U/L in N2 sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90 min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimisation of L. reuteri DSM 17938.}},
  author       = {{Seshagiri Rao, Nikhil and Ermann Lundberg, Ludwig and Tomasson, Julia and Tullberg, Cecilia and Brink, Daniel P. and Bai Palmkron, Shuai and van Niel, Ed W. J. and Håkansson, Sebastian and Carlquist, Magnus}},
  issn         = {{1664-302X}},
  keywords     = {{Online flow cytometry; K Mean clustering; Fatty acid (FA); Bile and Acid Tolerance; 5' Nucleotidase; Limosilactobacillus reuteri DSM 17938; Oxygen; Freeze-drying (FD)}},
  language     = {{eng}},
  publisher    = {{Frontiers Media S. A.}},
  series       = {{Frontiers in Microbiology}},
  title        = {{Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in <i>Limosilactobacillus reuteri</i> DSM 17938}},
  url          = {{https://lup.lub.lu.se/search/files/144244901/fmicb_14_1152389.pdf}},
  doi          = {{10.3389/fmicb.2023.1152389}},
  volume       = {{14}},
  year         = {{2023}},
}