γ-Aminobutyric acid production by selected lactic acid bacteria isolate of an Indonesian indigenous fermented buffalo milk (dadih) origin

Fermentation of Polygonati Rhizoma aqueous extract using Lactiplantibacillus plantarum under the condition of eutrophication

In this experiment, the eutrophication system was established by adding sucrose and yeast powder, and the pH and dissolved oxygen were measured in a bioreactor in real time to study the effect of aerobic environment on the fermentation process of Polygonati Rhizoma extract by Lactiplantibacillus plantarum. To further analyze metabolic changes, UPLC-Q-Exactive MS was used for metabolomic analysis and metabolic profiling. Multivariate analysis was performed using principal component analysis and Orthogonal projections to latent structures discriminant analysis. Finally, 313 differential metabolites were selected, 196 of which were annotated through database matching. After fermentation, the content of short-chain fatty acids, lactic acid, and their derivatives increased significantly, and there were 13 kinds and 4 kinds, respectively. Both compounds and their derivatives are beneficial to the intestinal flora. Consequently, incorporating L. plantarum into the aerobic fermentation process of Polygonati Rhizoma extract within the eutrophic system is potentially advantageous in enhancing the impact of its fermentation solution on the gut microbiota and its effects on human health. Our findings for this kind of edible and medicinal material research and development offer useful insights.

Production and quality evaluation of a novel γ-aminobutyric acid-enriched yogurt

Objective

γ-aminobutyric acid (GABA) is a neurotransmitter inhibitor that has beneficial effects on various health conditions such as hypertension, cognitive dysfunction, and anxiety. In this study, we investigated a novel yogurt naturally enriched with GABA using a Levilactobacillus brevis strain isolated in our laboratory; the specific optimum yogurt production conditions for this strain were determined.

Methods

We isolated an L. brevis strain and used it to produce yogurt naturally enriched with GABA. We explored the optimal conditions to enhance GABA yield, including fermentation temperature, inoculation amount, L-monosodium glutamate (L-MSG) concentration, fermentation time, and sucrose content. We also performed mixed fermentation with Streptococcus thermophilus and evaluated the quality of the yogurt.

Results

Following optimization (43°C, 8% inoculation amount, 1.5 g/L L-MSG, and 8% sucrose for 40 h of fermentation), the GABA yield of the yogurt increased by 2.2 times, reaching 75.3 mg/100 g. Mixed fermentation with S. thermophilus demonstrated favorable results, achieving a GABA yield akin to that found in some commercially available functional foods. Moreover, the viable microbe count in the GABA-enriched yogurt exceeded 1 × 108 cfu/mL, which is higher than that of commercial standards. The yogurt also exhibited a suitable water-holding capacity, viscosity, 3-week storage time, and favorable sensory test results.

Conclusion

This study highlights the potential of naturally enriched GABA yogurt as a competitive commercial yogurt with beneficial health effects.

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

γ-Aminobutyric acid (GABA) is an important nonprotein amino acid that extensively exists in nature. At present, GABA is mainly obtained through chemical synthesis, plant enrichment, and microbial production, among which microbial production has received widespread attention due to its safety and environmental benefits. After using microbial fermentation to obtain GABA, it is necessary to be isolated and purified to ensure its quality and suitability for various industries such as food, agriculture, livestock, pharmaceutics, and others. This article provides a comprehensive review of the different sources of GABA, including its presence in nature and the synthesis methods. The factors affecting the production of microbial-derived GABA and its isolation and purification methods are further elucidated. Moreover, the main physiological functions of GABA and its application in different fields are also reviewed. By advancing our understanding of GABA, we can unlock its full potential and further utilize it in various fields to improve human health and well-being.

Ascertaining the Influence of Lacto-Fermentation on Changes in Bovine Colostrum Amino and Fatty Acid Profiles

The aim of this study was to collect samples of bovine colostrum (BCOL) from different sources (agricultural companies A, B, C, D and E) in Lithuania and to ascertain the influence of lacto-fermentation with Lactiplantibacillus plantarum strain 135 and Lacticaseibacillus paracasei strain 244 on the changes in bovine colostrum amino (AA), biogenic amine (BA), and fatty acid (FA) profiles. It was established that the source of the bovine colostrum, the used LAB, and their interaction had significant effects (p < 0.05) on AA contents; lactic acid bacteria (LAB) used for fermentation was a significant factor for aspartic acid, threonine, glycine, alanine, methionine, phenylalanine, lysine, histidine, and tyrosine; and these factor's interaction is significant on most of the detected AA concentrations. Total BA content showed significant correlations with glutamic acid, serine, aspartic acid, valine, methionine, phenylalanine, histidine, and gamma amino-butyric acid content in bovine colostrum. Despite the differences in individual FA contents in bovine colostrum, significant differences were not found in total saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids. Finally, the utilization of bovine colostrum proved to be challenging because of the variability on its composition. These results suggest that processing bovine colostrum into value-added formulations for human consumption requires the adjustment of its composition since the primary production stage. Consequently, animal rearing should be considered in the employed bovine colostrum processing technologies.

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.

Probiotic Properties and Optimization of Gamma-Aminobutyric Acid Production by Lactiplantibacillus plantarum FBT215

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 μg/ml, while it was 1812.16 ± 23.16 μg/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

Potent γ-amino butyric acid producing psychobiotic Lactococcus lactis LP-68 from non-rhizospheric soil of Syzygium cumini (Black plum)

Gamma amino butyric acid (GABA) is a chemical messenger that plays a significant role in muscle relaxation and brain health. Certain lactic acid bacteria (LAB) produce significant levels of GABA and thus act as potential psychobiotic cultures. In the present study, LAB were isolated from non-rhizospheric soil sample of Syzygium cumini (Black plum). A total of 57 LAB were isolated on the basis of their morphological and acid producing characteristic on de Man Rogosa Sharpe (MRS) agar. Only seven isolates were found to produce GABA (0.09-1.13 gL^-1) in MRS broth and were identified as Lactococcus. However, L. lactis LP-68 produced highest amount of GABA and was selected for further optimization of culture conditions (pH, temperature and MSG) by response surface methodology (RSM). The optimization resulted in approximately four-fold increase in GABA production (4.11 gL^-1). The results indicate that the L. lactis LP-68 can be used as starter culture for production of GABA-enriched functional foods.

Isolation, identification and characterization of L actobacillus species diversity from Meekiri: traditional fermented buffalo milk gels in Sri Lanka

Traditional fermented buffalo milk gel; Meekiri, is a popular buffalo milk-derived product in Sri Lanka. Predominantly, it is produced using the back-slopping (adding a small amount of the previous fermentate) technique, following the life-long traditions available at the cottage level. Hence, diverse and unclassified starter cultures are likely to be established across the varying geographical regions of Meekiri production. In the present study, we aimed to elucidate the diversity of lactic acid bacteria (LAB) and their characteristics including probiotic properties from major Meekeri production areas (n = 22) in Sri Lanka. Lactic acid bacteria was isolated from locally produced Meekiri samples (n = 23) and characterized based on morphological, biochemical, physiological profiles and potential of probiotic properties. The isolates revealed five different colony and cell morphologies and were classified as heterofermenters, homofermenters and facultative heterofermenters based on CO2 production using glucose. None of the isolates showed the ability to grow either at 5 °C or 0 °C, while 71 % and 100 % survival of the isolates were observed at 15 °C and 45 °C, respectively. Amplified ribosomal DNA restriction analysis (ARDRA) primarily grouped the isolates into three distinct clusters based on their DNA banding patterns. Subsequently, 16S rRNA sequencing of isolates revealed the presence of four species namely, Limosilactobacillus fermentum (n = 18), Latilactobacillus curvatus (n = 2), Lactobacillus acidophilus (n = 2) and Lactiplantibacillus plantarum (n = 1) and in the phylogenetic analysis, it was represented by four distinctive clades. All the isolated species demonstrated promising probiotic potential with antibiotic sensitivity, antimicrobial properties, bile acid tolerance and acid tolerance. In conclusion, traditional back-slopping Meekiri in Sri Lanka contains diverse LAB, with a negligible geographical variation at species-level. Our work provides a strong foundation and insights into future applications in starter culture development for the fermentation of buffalo's milk.

Characterization of Dadih: Traditional Fermented Buffalo Milk of Minangkabau

Dadih or dadiah is traditional fermented buffalo milk of Minangkabau, which occurs spontaneously. Dadih is commonly served as ampiang dadih, or other dishes. The microbiota found in dadih are dominated by lactic acid bacteria, and yeasts are also found. The lactic acid bacteria provide functional value, such as antimicrobial, hypocholesterolemic, antimutagenic, antioxidant, and immunomodulatory properties, as well as being the source of γ-aminobutyric acid (GABA) as an anti-stress agent and folate. Nevertheless, many challenges were observed in dadih production, including the limitation of buffalo milk production due to decreasing populations of buffalo in the last two decades, unstandardized dadih production due to the spontaneous fermentation in natural bamboo tubes, and safety problems as no heat treatment is applied in the production of dadih. These problems impede the development of dadih production, thus is it important to improve buffalo cultivation through artificial insemination programs, using different types of milk and pasteurization processes in dadih production, and incubator development to accelerate the fermentation period.

Multi-Strain Probiotics: Synergy among Isolates Enhances Biological Activities

The use of probiotics for health benefits is becoming popular because of the quest for safer products with protective and therapeutic effects against diseases and infectious agents. The emergence and spread of antimicrobial resistance among pathogens had prompted restrictions over the non-therapeutic use of antibiotics for prophylaxis and growth promotion, especially in animal husbandry. While single-strain probiotics are beneficial to health, multi-strain probiotics might be more helpful because of synergy and additive effects among the individual isolates. This article documents the mechanisms by which multi-strain probiotics exert their effects in managing infectious and non-infectious diseases, inhibiting antibiotic-resistant pathogens and health improvement. The administration of multi-strain probiotics was revealed to effectively alleviate bowel tract conditions, such as irritable bowel syndrome, inhibition of pathogens and modulation of the immune system and gut microbiota. Finally, while most of the current research focuses on comparing the effects of multi-strain and single-strain probiotics, there is a dearth of information on the molecular mechanisms of synergy among multi-strain probiotics isolates. This forms a basis for future research in the development of multi-strain probiotics for enhanced health benefits.

γ-Aminobutyric acid found in fermented foods and beverages: current trends

γ-aminobutyric acid (GABA) is synthesised by glutamic acid decarboxylase which catalyses the decarboxylation of L-glutamic acid. L-glutamic acid is formed by α-ketoglutarate in the TCA cycle by glutamic acid dehydrogenase (GDH). GABA is found in the human brain, plants, animals and microorganisms. GABA functions as an antidepressant, antihypertensive, antidiabetic and immune system enhancer and has a good effect on neural disease. As GABA have pharmaceutical properties, conditions for GABA production need to be established. Microbiological GABA production is more safe and eco-friendly rather than chemical methods. Moreover, it is easier to control conditions of production using microorganisms compared to production in plants and animals. GABA production in fermented foods and beverages has the potential to be optimised to increase the functional effect of fermented foods and beverages.

A Brief Review on the Non-protein Amino Acid, Gamma-amino Butyric Acid (GABA): Its Production and Role in Microbes

Gamma-Aminobutyric acid (GABA) is a non-protein amino acid widely distributed in nature. It is produced through irreversible α-decarboxylation of glutamate by enzyme glutamate decarboxylase (GAD). GABA and GAD have been found in plants, animals, and microorganisms. GABA is distributed throughout the human body and it is involved in the regulation of cardiovascular conditions such as blood pressure and heart rate, and plays a role in the reduction of anxiety and pain. Although researchers had produced GABA by chemical method earlier it became less acceptable as it pollutes the environment. Researchers now use a more promising microbial method for the production of GABA. In the drug and food industry, demand for GABA is immense. So, large scale conversion of GABA by microbes has got much attention. So this review focuses on the isolation source, production, and functions of GABA in the microbial system. We also summarize the mechanism of action of GABA and its shunt pathway.