Gamma-aminobutyric Acid Yield Research Articles

Spent coffee grounds as a potential culture medium for γ-aminobutyric acid (GABA) production by Levilactobacillus brevis PML1

This study aimed to investigate the Gamma-aminobutyric acid (GABA) production potential of Levilactobacillus brevis PML1 using an industrial waste-based culture medium. The optimization of GABA production was carried out in Spent Coffee Grounds (SCG) medium employing Response Surface Methodology (RSM). A Central Composite Design (CCD) was employed, revealing that the optimal SCG treatment conditions were as follows: 6% H2SO4 concentration, 120 min incubation, 0.14 mL Accellerase-1000 enzyme. High-performance chromatography analysis demonstrated a GABA yield of 492 mg/L after 48 h at 37 °C when supplemented with 3% monosodium glutamate. The antimicrobial activity assessment exhibited sensitivity towards Staphylococcus aureus among tested pathogenic bacteria. Scanning electron microscopy elucidated the antibacterial mechanism on Escherichia coli and S. aureus as representative strains. Furthermore, radical inhibitory activities were observed through DPPH assay recording a maximum inhibition rate of 13.15%, while FRAP assay indicated an antioxidant capacity of up to 0.419 mmol/L. Also, L. brevis demonstrated 53.40% cholesterol removal capability. Cytotoxic effects on human colon cancer cell lines Caco-2 were examined using MTT assay, yielding an IC50 value of approximately 3.25 g/mL for the extracts. In conclusion, this study highlights that SCG can serve as an affordable culture medium for efficient metabolite production.

The impact of Levilactobacillus brevis YSJ3 and Lactiplantibacillus plantarum JLSC2-6 co-culture on gamma-aminobutyric acid yield, volatile and non-volatile metabolites, antioxidant activity, and bacterial community in fermented cauliflower byproducts

Co-culture fermentation is a novel technology for enhancing fermentation quality and promoting gamma-aminobutyric acid (GABA) yield. The purpose of this study was to evaluate the effects of Levilactobacillus brevis YSJ3 and Lactiplantibacillus plantarum JLSC2-6 co-culture on GABA yield, volatile and non-volatile metabolite profiles, and antioxidant activity in cauliflower byproducts. It was found that co-culture had the highest GABA yield (35.00 ± 1.15 mg/L) in fermented cauliflower stems. In total, 111 and 1264 volatile and non-volatile metabolites, respectively, were identified, of which 59 metabolites were significantly upregulated after co-culture fermentation. The results showed that 24 key upregulated metabolites were positively associated with hydroxyl radical-scavenging activity. Notably, Levilactobacills were positively correlated with the yield of GABA and key upregulated metabolites. Thus, these results suggest that Levilactobacillus brevis and Lactiplantibacillus plantarum can improve in key metabolites, GABA yield, and antioxidant activity following co-culture. This study provide a theoretical basis for developing GABA-rich cauliflower byproducts.

Optimization of Gamma-Aminobutyric Acid Production by Lactiplantibacillus plantarum FRT7 from Chinese Paocai.

Gamma-aminobutyric acid (GABA) is a widely available non-protein amino acid whose physiological importance goes beyond its role as an inhibitory neurotransmitter in mammals. The GABA synthesis ability of ten strains of Lactiplantibacillus plantarum was screened. They produced GABA ranging from 48.19 ± 3.44 to 100.75 ± 1.63 mg/L at 24 h-cultivation. Among them, Lp. plantarum FRT7 showed the highest GABA production. Therefore, FRT7 was chosen for GABA yield optimization. A one-factor-at-a-time strategy analysis of the GABA yield of FRT7 was performed, including the culture temperature, incubation time, inoculum volume, initial pH, the initial amount of monosodium glutamate (MSG), and pyridoxal 5'-phosphate (PLP) concentration, based on which the response surface methodology (RSM) was performed. After being cultured in an MRS culture medium supplemented with 3% MSG and 2 mmol/L of PLP at 40 °C with an initial pH of 7.0 for 48 h, the GABA reached a maximum yield of 1158.6 ± 21.22 mg/L. The results showed the experimental value of the GABA yield was in good agreement with the predicted values. Furthermore, the results from the RSM also indicated that the initial MSG addition, PLP concentration, and incubation time were significant variables. These results suggest that Lp. plantarum FRT7 has the potential to be a health-beneficial probiotic with commercial capabilities.

Optimizing Levilactobacillus brevis NPS-QW 145 Fermentation for Gamma-Aminobutyric Acid (GABA) Production in Soybean Sprout Yogurt-like Product

Gamma-aminobutyric acid (GABA) is a non-protein amino acid with various physiological functions. Levilactobacillus brevis NPS-QW 145 strains active in GABA catabolism and anabolism can be used as a microbial platform for GABA production. Soybean sprouts can be treated as a fermentation substrate for making functional products. This study demonstrated the benefits of using soybean sprouts as a medium to produce GABA by Levilactobacillus brevis NPS-QW 145 when monosodium glutamate (MSG) is the substrate. Based on this method, a GABA yield of up to 2.302 g L-1 was obtained with a soybean germination time of one day and fermentation of 48 h with bacteria using 10 g L-1 glucose according to the response surface methodology. Research revealed a powerful technique for producing GABA by fermentation with Levilactobacillus brevis NPS-QW 145 in foods and is expected to be widely used as a nutritional supplement for consumers.

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

Probiotic metabolites, known as postbiotics, have received attention due to their wide variety of promoting health effects. One of the most exciting postbiotic is gamma-aminobutyric acid (GABA), widely produced by lactic acid bacteria, due to its benefits in health. In addition, the performance of the biosynthesis of GABA by Lactiplantibacillus plantarum could be modulated through the modification of fermentation parameters. Due to their high nutritional value, agri-food by-products could be considered a useful fermentation source for microorganisms. Therefore, these by-products were proposed as fermentation substrates to produce GABA in this study. Previously, several experiments in Man Rogosa Sharpe (MRS) broth were performed to identify the most critical parameters to produce GABA using the strain Lactiplantibacillus plantarum K16. The percentage of inoculum, the initial pH, and the concentration of nutrients, such as monosodium glutamate or glucose, significantly affected the biosynthetic pathway of GABA. The highest GABA yield was obtained with 500 mM of monosodium glutamate and 25 g/L of glucose, and an initial pH of 5.5 and 1.2% inoculum. Furthermore, these investigated parameters were used to evaluate the possibility of using tomato, green pepper, apple, or orange by-products to get GABA-enriched fermented media, which is an excellent way to revalorise them.

Critical Optimized Conditions for Gamma-Aminobutyric Acid (GABA)-Producing Tetragenococcus Halophilus Strain KBC from a Commercial Soy Sauce Moromi in Batch Fermentation

Gamma-aminobutyric acid (GABA) has several health-promoting qualities, leading to a growing demand for natural GABA production via microbial fermentation. The GABA-producing abilities of the new Tetragenococcus halophilus (THSK) isolated from a commercial soy sauce moromi were proven in this investigation. Under aerobic conditions, the isolate produced 293.43 mg/L of GABA after 5 days of cultivation, compared to 217.13 mg/L under anaerobic conditions. Critical parameters such as pH, monosodium glutamate (MSG), and sodium chloride (NaCl) concentrations were examined to improve GABA yield. MSG had the most significant impact on GABA and GABA synthesis was not suppressed even at high NaCl concentrations. Data showed that a pH of 8, MSG content of 5 g/L, and 20% NaCl were the best culture conditions. The ultimate yield was improved to 653.101 mg/L, a 2.22-fold increase (293.43 mg/L). This design shows that the bacteria THSK has industrial GABA production capability and can be incorporated into functional food.

Immunomodulatory Properties of a γ-Aminobutyric Acid-Enriched Strawberry Juice Produced by Levilactobacillus brevis CRL 2013.

Gamma-aminobutyric acid (GABA) plays a key role in mammals as the major inhibitory neurotransmitter of the central nervous system. Although GABA may not be able to cross the human blood-brain barrier, it was approved as a food ingredient because of its benefits to the host after oral administration including anti-hypertensive, anti-depressant and anti-inflammatory activities. Considering the current trend toward the development of new functional and natural products and that microbial fermentation is one of the most promising methods to produce this non-protein amino acid, the in situ production of GABA through fermentation of strawberry and blueberry juices by the efficient GABA producer strain, Levilactobacillus brevis (formerly known as Lactobacillus brevis) CRL 2013, was evaluated. A high GABA production (262 mM GABA) was obtained after fermenting strawberry juice supplemented with yeast extract for 168 h, being GABA yield significantly higher in strawberry juices than in the blueberry ones. Thus, GABA-enriched fermented strawberry juice (FSJ) was selected to carry out in vivo and in vitro studies. The in vitro functional analysis of the GABA-enriched FSJ demonstrated its ability to significantly decrease the expression of cox-2 gene in LPS stimulated RAW 264.7 macrophages. In addition, in vivo studies in mice demonstrated that both, L. brevis CRL 2013 and the GABA-enriched FSJ were capable of reducing the levels of peritoneal, intestinal and serum TNF-α, IL-6, and CXCL1, and increasing IL-10 and IFN-γ in mice exposed to an intraperitoneal challenge of LPS. Of note, the GABA-enriched FSJ was more efficient than the CRL 2013 strain to reduce the pro-inflammatory factors and enhance IL-10 production. These results indicated that the CRL 2013 strain exerts anti-inflammatory effects in the context of LPS stimulation and that this effect is potentiated by fermentation. Our results support the potential use of L. brevis CRL 2013 as an immunomodulatory starter culture and strawberry juice as a remarkable vegetable matrix for the manufacture of GABA-enriched fermented functional foods capable of differentially modulating the inflammatory response triggered by TLR4 activation.

High hydrostatic pressure increases the biosynthesis of γ-aminobutyric acid using bee pollen as a novel and eco-friendly catalyst

Gamma-amino butyric acid (GABA) has antihypertensive and anti-stress effects on human health. High hydrostatic pressure (HHP), a nonthermal treatment, has been documented as a novel approach to enhance the nutritional quality and functional components of plant-based food. In this study, a novel method to convert monosodium glutamate (MSG) to GABA using bee pollen as a natural catalyst was observed, and the GABA yield was improved by HHP treatment. Firstly, GABA production was confirmed by high performance liquid chromatography (HPLC) and tandem mass spectrometry (MS-MS), the highest GABA production was found in lotus bee pollen (LBP) when different varieties of bee pollen were used for the reaction. Secondly, the reaction conditions were utilized, and the optimal reaction condition of the GABA production was determined as described below: 250 mg/mL of bee pollen mixed with 590 mmol/L of MSG that prepared by 80 mmol/L of phosphate buffer (pH 5.8), and incubated at 40 °C for 6 h. For HHP treatment conditions, a treatment of 200 MPa for 10 min at 40 °C was found as the optimal. Under optimal conditions, GABA production reached 508.79 mmol/L (containing GABA from LBP) from 590 mmol/L of MSG. In conclusion, we found and optimized a novel method to convert monosodium glutamate (MSG) to GABA, and proposed the promotion of HHP on GABA bio-conversion.

Gamma-aminobutyric acid (GABA) production in milk fermented by specific wild lactic acid bacteria strains isolated from artisanal Mexican cheeses

PurposeThe purpose of this study was to screen wild GABA-producing lactic acid bacteria (LAB) isolated from artisanal Mexican cheeses and to evaluate the fermentation conditions for the enhancement of the GABA yield in fermented milk.MethodsA qualitative test was carried out to select the GABA-producing LAB and the GABA was quantified by reversed-phase high-performance liquid chromatography in fermented milk (FM). Two inoculum concentrations (107 and 109 CFU/mL), two incubation temperatures (30 and 37 °C), three glutamate concentrations (1, 3, and 5 g/L), and three pyridoxal 5′-phosphate (PLP) concentrations (0, 100, and 200 μM) were assessed to establish suitable conditions to enhance the GABA yield in FM.ResultsResults showed that, from a total of 94 LAB strains, fermented milk with two Lactococcus lactis strains (L-571 or L-572) presented the highest GABA production. However, 37 °C of incubation and 109 CFU/mL and 3 g/L of glutamate significantly led the highest GABA yield in FM with L-571. Further studies are needed to establish the optimum conditions for producing GABA by this strain, and in vivo studies may reveal its potential use as GABA-producing culture.ConclusionThese results highlight the importance of wild LAB strains in order to generate new alternatives and opportunities in the development of functional foods containing GABA.

Statistical optimization of γ-aminobutyric acid production by response surface methodology and artificial neural network models using Lactobacillus fermentum isolated from palm wine

Abstract The aim of this study was to screen and optimize gamma amino butyric acid (GABA) production by Lactobacillus fermentum (Lb. fermentum) in soybean milk and De Man- Rogosa Sharp (MRS) media. The GABA yield was confirmed by thin layer chromatography and quantitatively estimated by ninhydrine method. Response surface methodology (RSM), a statistical tool was applied for optimization of GABA yield. The accuracy of RSM predicted results were demonstrated by a non-statistical (hypothetical) model using Artificial Neural Network (ANN). On TLC plate GABA produced by Lb. fermentum showed same Rf value (0.54) compared with standard GABA. Lb. fermentum produced 6.94 g/L and 3.07 g/L of GABA in MRS media and soymilk respectively. After optimization there was 1.7 fold increase in the GABA yield in optimized conditions when compared to unoptimized soybean milk. In single variable optimization Monosodium glutamate (MSG), glucose and incubation period (IP) were found to favor for GABA production. Through RSM model the maximum predicted GABA yield (5.34 g/L) was observed with a concentration of 1.5% of MSG and 1.19% of glucose with 48 h of incubation. This is the first report on production of GABA in soybean milk by Lb. fermentum isolated from palm wine. Production of GABA by Lb. fermentum in soymilk as a basal substrate, is economical in comparison with synthetic media (MRS). This convincing results from this study could be a touchstone for exploring Lb. fermentum strain to obtain GABA enriched functional food for human consumption.

Optimization of gamma-aminobutyric acid production in a model system containing soy protein and inulin by Lactobacillus brevis fermentation

Gamma-aminobutyric acid (GABA) is an active bio-compound with versatile physiological functions and, therefore, considerable attention is given to developing GABA-enriched functional foods. In this study, central composite design was used to optimize the fermentation conditions to obtain the highest GABA yield by Lactobacillus brevis. The optimal conditions of GABA production (1473.44 ppm) included 5% soy protein isolate, 3% inulin, and 96 h fermenting time at 37 °C. GABA-rich fermented solution (GABA-EFS) under optimal conditions had an appropriate emulsifying activity and water/oil holding capacity. Also, the reducing power assay revealed that GABA-EFS has electron donor groups with the ability to terminate the free radical chain reactions. Minimum inhibitory concentration results showed that Candida albicans was the most sensitive microorganism; whilst, Staphylococcus aureus and Listeria innocua were the most resistant bacteria towards GABA-EFS. In addition, GABA production was confirmed by pre-staining thin layer chromatography and fourier transform infrared spectroscopy. The results suggested that the GABA-EFS could be applied in the food industry as a functional product.

Introduction of synthetic protein complex between Pyrococcus horikoshii glutamate decarboxylase and Escherichia coli GABA transporter for the improved production of GABA

Gamma-aminobutyric acid (GABA) is a precursor to pyrrolidone, a monomer used for the production of a biodegradable polymer known as nylon-4. GABA is also widely used in the medical industry to treat conditions such as high blood pressure, anxiety and depression. Generally, GABA is produced from glutamate by the enzyme glutamate decarboxylase (GadB). In this study, a synthetic scaffold complex was introduced between Pyrococcus horikoshii GadB and the GABA antiporter (GadC) from E. coli. P. horikoshii GadB was attached to the N-terminus, C-terminus and middle of E. coli GadC via scaffolding. Among the three scaffold complexes evaluated, the N-terminus scaffold model produced 5.93g/L of GABA from 10g/L monosodium glutamate (MSG). When the gabT mutant E. coli XBT strain was used, the highest GABA concentration of 5.96g/L was obtained, which is 97.8% of GABA yield. In addition to GABA concentration, GABA productivity was increased 3.5 fold via the synthetic scaffold complex.

Whole-cell conversion of l-glutamic acid into gamma-aminobutyric acid by metabolically engineered Escherichia coli.

A simple and high efficient way for the synthesis of gamma-aminobutyric acid (GABA) was developed by using engineered Escherichia coli as whole-cell biocatalyst from l-glutamic acid (l-Glu). Codon optimization of Lactococcus lactis GadB showed the best performance on GABA production when middle copy-number plasmid was used as expression vector in E. coli BW25113. The highest production of GABA reached 308.96 g L−1 with 99.9 mol% conversion within 12 h, when E. coli ΔgabAB (pRB-lgadB) concentrated to an OD600 of 15 in 3 M l-Glu at 45 °C. Furthermore, the strain could be reused at least three cycles in 2 M crude l-Glu with an average productivity of 40.94 g L−1 h−1. The total GABA yield reached 614.15 g L−1 with a molar yield over 99 %, which represented the highest GABA production ever reported. The whole-cell bioconversion system allowed us to achieve a promising cost-effective resource for GABA in industrial application.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2217-2) contains supplementary material, which is available to authorized users.

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production.

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products.

Improvement of gamma-amino butyric acid production by an overexpression of glutamate decarboxylase from Pyrococcus horikoshii in Escherichia coli

In this study, the effect of glutamate decarboxylase from Pyrococcus horikoshii on gamma-aminobutyric acid (GABA) production was investigated in Escherichia coli for the first time. E. coli with overexpressed P. horikoshii glutamate decarboxylase was cultured at various pH levels and temperatures to determine the optimum conditions for GABA production. The highest final GABA concentration, 5.07 g/L, was obtained from 10 g/L of monosodium glutamate (MSG) with a GABA yield of 83% at 30°C and pH 3.5. When P. horikoshii glutamate decarboxylase was introduced into a GABA aminotransferase knock-out E. coli XBT strains, 5.69 g/L of GABA was produced with a GABA yield of 93%.

재조합 Escherichia coli를 이용한 gamma-Aminobutyric Acid 전환 반응 최적화

In this study, the effects of pH, temperature, IPTG concentration and substrate (MSG) concentration on gamma-aminobutyric acid (GABA) production in engineered Escherichia coli were investigated. Glutamate decarboxylase and glutamate/GABA antiporter were overexpressed in GABA aminotransferase knock-out strain for GABA production. The result of optimization study showed the GABA bioconversion was optimized at pH 3.5, <TEX>$30^{\circ}C$</TEX>, 0.5 mM IPTG, 10 g/L MSG. At this condition, 5.23 g/L of final GABA concentration of was achieved from 10 g/L of MSG, which corresponded to a GABA yield of 85.77%.

Effects of glutamate decarboxylase and gamma-aminobutyric acid (GABA) transporter on the bioconversion of GABA in engineered Escherichia coli

Gamma-aminobutyric acid (GABA) is a non-essential amino acid and a precursor of pyrrolidone, a monomer of nylon 4. GABA can be biosynthesized through the decarboxylation of L: -glutamate by glutamate decarboxylase. In this study, the effects of glutamate decarboxylase (gadA, gadB), glutamate/GABA antiporter (gadC) and GABA aminotransferase (gabT) on GABA production were investigated in Escherichia coli. Glutamate decarboxylase was overexpressed alone or with the glutamate/GABA antiporter to enhance GABA synthesis. GABA aminotransferase, which redirects GABA into the TCA cycle, was knock-out mutated. When gadB and gadC were co-overexpressed in the gabT mutant strain, a final GABA concentration of 5.46 g/l was obtained from 10 g/l of monosodium glutamate (MSG), which corresponded to a GABA yield of 89.5%.

Optimisation of Fermentative Parameters for GABA Enrichment by Lactococcus lactis

Gamma-aminobutyric acid (GABA) has antihypertensive and anti-stress functions on humans. Submerged fermentation of Lactoccocus lactis was regarded as an effective method to obtain GABA. In this study, the effects of fermentative parameters on the production of GABA was investigated. Firstly, one-variable-at-a-time experiments were performed in order to investigate the effects of significant factors influencing the GABA yield and monosodium glutamate (MSG) mole transformation percentage, i.e, the culture temperature, initial pH of the medium, MSG addition, and MSG addition time. Then, the response surface methodology (RSM) was applied to determine the optimum fermentative parameters. The results indicated that MSG addition was the most significant factor influencing GABA yield and MSG mole transformation percentage. The optimum parameters obtained by RSM for GABA enrichment by Lactoccocus lactis subsp. lactis (L. lactis) are listed as follows: temperature 31.8°C, pH 7.1 and MSG addition 15 g/l. Under these conditions, the predicted values were: GABA maximum 7.2 g/l and MSG mole transformation percentage 68.4%.

Medium optimization for production of gamma-aminobutyric acid by Lactobacillus brevis NCL912

Production of gamma-aminobutyric acid (GABA) was carried out in Erlenmeyer flasks by Lactobacillus brevis NCL912. Traditional methods were first adopted to select the key factors that impact the GABA production to preliminarily determine the suitable concentration ranges of the key factors. It was found that glucose, soya peptone, Tween-80 and MnSO(4).4H(2)O were the key factors affecting GABA production. Then, response surface methodology was applied to analyze the optimum contents of the four key factors in the medium, and the production of GABA was predicted as 349.69 mM under the optimized conditions with this model. Afterward, the experiment was performed under the optimized conditions, and the yield of GABA reached 345.83 mM, which was 130% higher than the initial medium. The results showed that experimental yield and predicted values of GABA yield were in good agreement.

Application of artificial neural network coupling particle swarm optimization algorithm to biocatalytic production of GABA

The biotransformation of L-sodium glutamate (L-MSG) to gamma-aminobutyric acid (GABA) catalyzed by the cells of Lactobacillus brevis with higher glutamate decarboxylase activity was investigated. The results showed that pH, temperature, and FeSO(4) x 7H(2)O concentration had significantly positive effect on GABA yield. The individual and interactive effects of pH, temperature, and FeSO(4) x 7H(2)O concentration were further optimized in terms of GABA yield. In the present work, an artificial neural network (ANN) and response surface methodology (RSM) models were developed, which incorporated pH, temperature, and FeSO(4) x 7H(2)O concentration as input variables, and GABA yield as output variable. The optimized ANN topology included four neurons in the hidden layer and the best network architecture was 3-4-1. The trained ANN gave total root-mean square error (sigma) equal to 1.84 for GABA yield while the RSM gave sigma equal to 2.63. The results demonstrated a slightly higher prediction accuracy of ANN compared to RSM. The modeled maximum GABA yield was identified by applying particle swarm optimization algorithm to the ANN model developed. The modeled maximum GABA yield reached 91 mM under the following optimal conditions: 25 mL Na(2)HPO(4)-citric acid buffer (100 mM, pH 4.23), 120 mM L-MSG, 0.83 g/L FeSO(4) x 7H(2)O, 10 microM PLP, the resting cells obtained from a 60-h culture broth, 2.68 g dry cell weight (DCW)/L, and without agitation at 40 degrees C for 5 h. The previous high value of GABA yield that was observed was 81.8 mM. The optimized conditions allowed GABA yield to be increased from 81.8 to 90.57 mM after verification experiments test.