Dataset Information

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

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 optimization of L. reuteri DSM 17938.

SUBMITTER: Rao NS

PROVIDER: S-EPMC10140318 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Rao Nikhil Seshagiri NS Ermann Lundberg Ludwig L Tomasson Julia J Tullberg Cecilia C Brink Daniel P DP Palmkron Shuai Bai SB van Niel Ed W J EWJ Håkansson Sebastian S Carlquist Magnus M

Frontiers in microbiology 20230414

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 o ...[more]

PMID: 37125176

Similar Datasets

Project description:Improved efficacy of probiotics can be achieved by using different strategies, including the optimization of production parameters. The impact of fermentation parameters on bacterial physiology is a frequently investigated topic, but what happens during the formulation, i.e., the step where the lyoprotectants are added prior to freeze-drying, is less studied. In addition to this, the focus of process optimization has often been yield and stability, while effects on bioactivity have received less attention. In this work, we investigated different metabolic activities of the probiotic strain Limosilactobacillus reuteri DSM 17938 during formulation with the freeze-drying protectant sucrose. We discovered that the strain consumed large quantities of the added sucrose and produced an exopolysaccharide (EPS). Using NMR, we discovered that the produced EPS was a glucan with α-1,4 and α-1,6 glycosidic bonds, but also that other metabolites were produced. The conversion of the lyoprotectant is hereafter designated lyoconversion. By also analyzing the samples with GCMS, additional potential bioactive compounds could be detected. Among these were tryptamine, a ligand for the aryl hydrocarbon receptor, and glycerol, a precursor for the antimicrobial compound reuterin (3-hydroxypropionaldehyde). To exemplify the bioactivity potential of lyoconversion, lyoconverted samples as well as purified EPS were tested in a model for immunomodulation. Both lyoconverted samples and purified EPS induced higher expression levels of IL-10 (2 times) and IL-6 (4-6 times) in peripheral blood mononuclear cells than non-converted control samples. We further found that the initial cultivation of DSM 17938 with sucrose as a sugar substrate, instead of glucose, improved the ability to convert sucrose in the lyoprotectant into EPS and other metabolites. Lyoconversion did not affect the viability of the bacteria but was detrimental to freeze-drying survival, an issue that needs to be addressed in the future. In conclusion, we show that the metabolic activities of the bacteria during the formulation step can be used as a tool to alter the activity of the bacteria and thereby potentially improve probiotic efficacy.

Dataset Information

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

Publications

Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in <i>Limosilactobacillus reuteri</i> DSM 17938.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets