Environmental Conditions Affecting GABA Production in Lactococcus lactis NCDO 2118

GABA (γ-aminobutyric acid) production has been widely described as an adaptive response to abiotic stress, allowing bacteria to survive in harsh environments. This work aimed to clarify and understand the relationship between GABA production and bacterial growth conditions, with particular reference...

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Bibliographic Details
Published in:Microorganisms (Basel) 2021-01, Vol.9 (1), p.122
Main Authors: Laroute, Valérie, Mazzoli, Roberto, Loubière, Pascal, Pessione, Enrica, Cocaign-Bousquet, Muriel
Format: Article
Language:English
Subjects:
Batch culture
Biomass
Chloride
Chloride ions
Complex media
Environmental conditions
Enzymes
Food
Functional foods & nutraceuticals
gamma-aminobutyric acid (GABA)
Gene expression
Glucose
Glutamate decarboxylase
Glutamic acid
Glycerol
Growth conditions
Harsh environments
Ions
Lactococcus lactis
Life Sciences
Microbiology and Parasitology
nutraceuticals
Osmolarity
osmotic stress
Polyols
Potassium
Salts
Sodium chloride
Sorbitol
Sulfates
γ-Aminobutyric acid
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Summary:GABA (γ-aminobutyric acid) production has been widely described as an adaptive response to abiotic stress, allowing bacteria to survive in harsh environments. This work aimed to clarify and understand the relationship between GABA production and bacterial growth conditions, with particular reference to osmolarity. For this purpose, NCDO 2118, a GABA-producing strain, was grown in glucose-supplemented chemically defined medium containing 34 mM L-glutamic acid, and different concentrations of salts (chloride, sulfate or phosphate ions) or polyols (sorbitol, glycerol). Unexpectedly, our data demonstrated that GABA production was not directly related to osmolarity. Chloride ions were the most significant factor influencing GABA yield in response to acidic stress while sulfate ions did not enhance GABA production. We demonstrated that the addition of chloride ions increased the glutamic acid decarboxylase (GAD) synthesis and the expression of the BC genes. Finally, under fed-batch conditions in a complex medium supplemented with 0.3 M NaCl and after a pH shift to 4.6, NCDO 2118 was able to produce up to 413 mM GABA from 441 mM L-glutamic acid after only 56 h of culture, revealing the potential of strains for intensive production of this bioactive molecule.
ISSN:2076-2607
2076-2607
DOI:10.3390/microorganisms9010122