High Production of γ-Aminobutyric Acid by Activating the xyl Operon of Lactobacillus brevis

Abstract

γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter with important physiological functions such as sleep assistance and anti-depression. In this study, we developed a fermentation process for the high-efficiency production of GABA by Lactobacillus brevis (Lb. brevis) CE701. First, xylose was found as the optimal carbon source that could improve the GABA production and OD 600 in shake flasks to 40.35 g/L and 8.64, respectively, which were 1.78-fold and 1.67-fold of the glucose. Subsequently, the analysis of the carbon source metabolic pathway indicated that xylose activated the expression of the xyl operon, and xylose metabolism produced more ATP and organic acids than glucose, which significantly promoted the growth and GABA production of Lb. brevis CE701. Then, an efficient GABA fermentation process was developed by optimizing the medium components using response surface methodology. Finally, the production of GABA reached 176.04 g/L in a 5 L fermenter, which was 336% higher than that in a shake flask. This work enables the efficient synthesis of GABA using xylose, which will provide guidance for the industrial production of GABA.

Gamma-Aminobutyric Acid (GABA) Producing Lactobacillus plantarum TSUB-17 and Probiotic Properties for Using as Probiotics Additive in Swine Feed

“…The most efficient GABA producers lactobacilli, were L. brevis [16,46], and L. plantarum [44]. This according to the previous report indicated the major source of GABA producing probiotic bacteria was lactic acid bacteria especially L. brevis and L. plantarum.…”

Multifunctional Probiotic and Safety Attributes Heyndrickxia coagulans Isolated from Stingless Bee Honey

“…The majority of research emphasizes the ability of lactobacilli, particularly L. brevis, to synthesize signi cant GABA quantities, with certain strains achieving concentrations of up to 176.04 g/L (Cha et al, 2023). Likewise, a few Bacillus strains, such as B. subtilis, have been documented to yield GABA levels around 12.5 g/L (Asun et al, 2022).…”

Microbial-Derived γ-Aminobutyric Acid: Synthesis, Purification, Physiological Function, and Applications

“…Among the gad operon-positive strains, Lactobacillus brevis was the only species with the highest probability (close to 100%) of carrying an intact gad operon in its chromosomes, making it an excellent candidate for GABA production . For example, Lactobacillus brevis NCL912 and Lactobacillus brevis CE701 are excellent GABA-producing bacterium, with a yield of 205.8 ± 8.0 g/L and 176.04 g/L, respectively. Moreover, other LAB, such as Enterococcus avium , Lactobacillus fermentum , Lactococcus lactis , and Lactobacillus paracasei are also excellent GABA-producing strains.…”

“…This could be attributed to the activation of the xyl operon when fermented with xylose instead of glucose, which could remarkably promote the growth of microorganisms and increase the content of GABA . Cha et al replaced glucose with xylose in the fermentation medium of Lactobacillus brevis CE701 and obtained a high GABA production of 176.04 g/L . Li et al reported that soya peptone, glucose, MnSO 4 ·4H 2 O, and Tween-80 were the main factors influencing GABA production.…”