Optimization of gamma-aminobutyric acid production by probiotic bacteria through response surface methodology

Abstract

Background and Objectives: Gamma-aminobutyric acid (GABA) is a non-protein four-carbon amino acid that has many physiological properties, including reducing blood pressure, accelerating protein synthesis in the brain, and treatment of insomnia and depression. This amino acid is produced by a number of lactic acid bacteria, fungi and yeasts. The objective of the present study was to identify probiotic bacteria with the maximum ability to generate GABA and optimize the bacterial culture conditions having the highest potential for GABA production.
 Materials and Methods: The potential of GABA production by Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Streptococcus thermophilus, Lactobacillus brevis and Lactococcus lactis ssp. lactis in the culture medium of MRS broth was assessed by High Performance Liquid Chromatography (HPLC). In order to increase the rate of GABA produced by the bacteria having the highest potential for GABA production, the conditions of the culture medium including pH (3.5 to 6.5) "temperature (25 to 45°C), time (12 to 96 h) and glutamic acid (GA) concentration (25 to 650 mmol) were optimized by the Box-Behnken’s Response Surface Method (RSM).
 Results: Lactobacillus brevis had the highest potential of GABA production (5960.8 mg/l). The effect of time and GA con- centration was significant on the amount of GABA production. The best conditions of culture medium to achieve the highest amount of GABA production by Lactobacillus brevis (19960 mg/l) were temperature 34.09°C, pH 4.65, GA concentration 650 mmol and time 96 h.
 Conclusion: The results showed that by optimization of the culture medium conditions of probiotic bacteria we can produce more GABA in culture medium

Strategies for improvement of gamma-aminobutyric acid (GABA) biosynthesis via lactic acid bacteria (LAB) fermentation

“…2 However, most of the LAB strains isolated from fermented foods such as yogurt, kimchi, pao cai, cheese and tea preferred an acidic pH. 113 GAD in LAB is only active under acidic conditions, in which the maximum yield of GABA is usually obtained at the pH ranging from 4.0 to 6.0, while at higher pH it may lose its activity or become denatured. 103,114 At the beginning of the LAB fermentation, the pH will acidify due to the substrate uptake and organic acid production.…”

“…1 In an optimization study using Box–Behnken's Response Surface Methodology (RSM), L. brevis TD10 grown in MRS media was found to reach the highest amount of GABA (19.9 g L −1 ) at pH 4.65. 113 In another report, the RSM model indicated pH (initial pH of 4.74) was the most significant factor for GABA production by L. brevis HYE1 that resulted in an experimental value of 18.76 mM, which was in agreement with the predicted value of 21.44 mM. 116 The highest GABA production by L. plantarum L10–11 was recorded in an initial pH range of MRS medium from 5.0 to 6.0, but was dramatically decreased at a pH below 4.0 or above 8.0.…”

Selection and identification of antibacterial and GABA-producing lactic acid bacteria from Vietnamese fermented meat

“…LAB are Gram-positive bacteria that are widely used in the food industry, especially in fermented product manufacturing, and exist in the intestines of both humans and animals. LAB plays a significant role in producing important biological compounds, including organic acids, vitamins, IOP Publishing doi:10.1088/1755-1315/1169/1/012095 2 aromatic compounds, bacteriocins, and organic enzymes [5]. LAB is considered a probiotic with many useful properties.…”

“…GABA is found extensively in microorganisms and synthesized primarily from the a-decarboxylation of L-glutamic acid or its salts, catalyzed by the enzyme glutamic acid decarboxylase (GAD) [4]. These microorganisms include fungi, yeasts, algae, and lactic acid bacteria; lactic acid bacteria (LAB) are the largest GABAproducing sources because of the diversity of the GAD system of LAB [5].…”

Biosynthesis of gamma-aminobutyric acid by Lactiplantibacillus plantarum K16 as an alternative to revalue agri-food by-products

“…Several studies have been conducted to adjust the main physic-chemical parameters involved in the GABA synthesis. For instance, Sharafi and Nateghi 29 optimised the GABA production by L. brevis by studying the effect of temperature, initial pH, l -Glu, concentration and fermentation time. They obtained that the fermentation carried out at 34 °C, with an initial pH of 4.65, 650 mmol of l -Glu and for 96 h of incubation time, enhanced more than twice the synthesis of GABA compared to non-optimised conditions.…”