Antioxidant activity and γ-aminobutyric acid (GABA) content in sea tangle fermented by Lactobacillus brevis BJ20 isolated from traditional fermented foods

Evaluation of gamma-aminobutyric acid (GABA) production by Lactobacillus plantarum using two-step fermentation

Lactic acid bacteria (Lactobacillus plantarum KCTC 3103) were fermented to produce gamma-aminobutyric acid (GABA). The conditions of the modified synthetic medium were optimized as 5 g/L glucose, 10 g/L yeast extract, 100 g/L rice bran extract, and 1.0 g/L ascorbic acid for GABA production. Single-step fermentation of cell growth and GABA production with a modified synthetic medium was higher than those with an MRS medium. Two-step fermentation was evaluated by separating the cell growth and GABA production under a modified synthetic medium. The cell concentration of 1.65 g dcw/L produced by the modified synthetic medium was higher than that of 1.0 g dcw/L produced by the MRS medium at 36 h from the first step of two-step fermentation. The highest GABA production of L. plantarum KCTC 3103 was 0.67 g/L with monosodium glutamate addition at 60 h in the second step of fermentation. Two-step fermentation with the modified synthetic medium is suitable for GABA production because of its high GABA productivity and favorable cell growth.

Evaluation of GABA Production and Probiotic Activities of Enterococcus faecium BS5

Gamma-aminobutyric acid (GABA) is a principal inhibitory neurotransmitter in the central nervous system and is produced by irreversible decarboxylation of glutamate. It possesses several physiological functions such as neurotransmission, diuretic, and tranquilizer effects and also regulates cardiovascular functions such as blood pressure and heart rate in addition to playing a role in the reduction of pain and anxiety. The objective of this study was to evaluate the GABA producing ability and probiotic capability of certain lactic acid bacteria strains isolated from dairy products. Around sixty-four bacterial isolates were collected and screened for their ability to produce GABA from monosodium glutamate, among which nine isolates were able to produce GABA. The most efficient GABA producer was Enterococcus faecium BS5. Further, assessment of several important and desirable probiotic properties showed that Ent. faecium BS5 was resistant to acid stress, bile salt, and antibiotics. Ent. faecium BS5 may potentially be used for large-scale industrial production of GABA and also for functional fermented product development.

Assessment of exopolysaccharides, bacteriocins and in vitro and in vivo hypocholesterolemic potential of some Egyptian Lactobacillus spp

Lactobacilli probiotics have been suggested to reduce cholesterol with low side effects to host. Bacteriocins and exopolysaccharides (EPSs) production are two meaningful examples of functional applications of lactobacilli in the food industry. Eight Lactobacillus strains were isolated from some Egyptian fermented food and tested for their probiotic properties. Analysis of the monosaccharide composition by thin layer chromatography showed the presence of glucose, galactose and unknown sugar. The main functional groups of EPSs were elucidated by Fourier-Transform Infrared Spectroscopy. Their fermentation cultures displayed powerful antioxidant activities extending from 97.5 to 99%, 40-75% for their EPSs and free cells, respectively, and exhibited in vitro cholesterol downgrading from 48 to 82% and 72 to 91% after 48 and 120 h, respectively. Their EPSs showed good anticancer activities against carcinoma cells with low IC₅₀ values for HCT-116, PC-3 and HepG-2 cells. To the best of our knowledge, there have been no previous reports on the potential of Lactobacillus EPSs activity against PC-3. The selected strains, L. plantarum KU985433 and L. rhamnosus KU985436 produced two different bacteriocins as detected by gel permeation chromatography with good antimicrobial activities. In vivo study demonstrated that feeding Westar rats with fermented milk exhibited greater cholesterol, LDL and blood triglyceride reduction for both strains. Whereas, HDL was increased by about 43 and 38%, respectively, and the atherogenic indices decreased.

Effects of nutritional interventions on BDNF concentrations in humans: a systematic review

Objectives: Brain-derived neurotrophic factor (BDNF) plays an essential role in brain and metabolic health. The fact that higher concentrations are associated with improved cognitive performance has resulted in numerous intervention trials that aim at elevating BDNF levels. This systematic review provides an overview of the relation between various nutritional factors and BDNF concentrations in controlled human intervention studies. Methods: A systematic search in May 2020 identified 48 articles that examined the effects of dietary patterns or foods (n = 3), diets based on energy intake (n = 7), vitamins and minerals (n = 7), polyphenols (n = 11), long-chain omega-3 polyunsaturated fatty acids (n = 5), probiotics (n = 8), and miscellaneous food supplements (n = 7). Results: In particular, studies with dietary patterns or foods showed increased peripheral BDNF concentrations. There are also strong indications that polyphenols tend to have a positive effect on BDNF concentrations. Four of the 11 included studies with a polyphenol intervention showed a significant increase in BDNF concentrations, one study showed an increase but this was not statistically analyzed, and two studies showed a trend to an increase. Discussion: The two polyphenol classes, phenolic acids, and other phenolic compounds were responsible for the significant effects. No clear effect was found for the other dietary factors, which might also be related to whether serum or plasma was used for BDNF analysis. More work is needed to understand the relation between peripheral and central BDNF concentrations.

Glutamate Decarboxylase from Lactic Acid Bacteria-A Key Enzyme in GABA Synthesis

Glutamate decarboxylase (l-glutamate-1-carboxylase, GAD; EC 4.1.1.15) is a pyridoxal-5’-phosphate-dependent enzyme that catalyzes the irreversible α-decarboxylation of l-glutamic acid to γ-aminobutyric acid (GABA) and CO₂. The enzyme is widely distributed in eukaryotes as well as prokaryotes, where it—together with its reaction product GABA—fulfils very different physiological functions. The occurrence of gad genes encoding GAD has been shown for many microorganisms, and GABA-producing lactic acid bacteria (LAB) have been a focus of research during recent years. A wide range of traditional foods produced by fermentation based on LAB offer the potential of providing new functional food products enriched with GABA that may offer certain health-benefits. Different GAD enzymes and genes from several strains of LAB have been isolated and characterized recently. GABA-producing LAB, the biochemical properties of their GAD enzymes, and possible applications are reviewed here.

In Vitro and In Vivo Effects of Fermented Oyster-Derived Lactate on Exercise Endurance Indicators in Mice

Exogenous lactate administration has more recently been investigated for its various prophylactic effects. Lactate derived from potential functional foods, such as fermented oyster extract (FO), may emerge as a practical and effective method of consuming exogenous lactate. The current study endeavored to ascertain whether the lactate derived from FO may act on muscle cell biology, and to what extent this may translate into physical fitness improvements. We examined the effects of FO in vitro and in vivo, on mouse C2C12 cells and exercise performance indicators in mice, respectively. In vitro, biochemical analysis was carried out to determine the effects of FO on lactate content and muscle cell energy metabolism, including adenosine triphosphate (ATP) activity. Western blot analysis was also utilized to measure the protein expression of total adenosine monophosphate-activated protein kinase (AMPK), p-AMPK (Thr172), lactate dehydrogenase (LDH), succinate dehydrogenase (SDHA) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) in response to FO administration. Three experimental groups were formed: a positive control (PC) treated with 1% horse serum, FO10 treated with 10 μg/mL and FO50 treated with 50 μg/mL. In vivo, the effects of FO supplementation on exercise endurance were measured using the Rota-rod test, and Western blot analysis measured myosin heavy-chain 2 (MYH2) to assess skeletal muscle growth, alongside p-AMPK, total-AMPK, PGC-1α, cytochrome C and UCP3 protein expression. Biochemical analysis was also performed on muscle tissue to measure the changes in concentration of liver lactate, lactate dehydrogenase (LDH), glycogen and citrate. Five groups (n = 10/per group) consisted of a control group (CON), exercise group (Ex), positive control treated with Ex and 500 mg/kg Taurine (Ex-Tau), Ex and 100 mg/kg FO supplementation (Ex-FO100) and Ex and 200 mg/kg FO supplementation (Ex-FO200) orally administered over the 4-week experimental period.FO50 significantly increased PGC-1α expression (p < 0.001), whereas both FO10 and FO50 increased the expression of p-AMPK (p < 0.001), in C2C12 muscle cells, showing increased signaling important for mitochondrial metabolism and biogenesis. Muscle lactate levels were also significantly increased following FO10 (p < 0.05) and FO50 (p < 0.001). In vivo, muscle protein expression of p-AMPK (p < 0.05) and PGC-1α were increased, corroborating our in vitro results. Cytochrome C also significantly increased following FO200 intake. These results suggest that the effects of FO supplementation may manifest in a dose-response manner. FO administration, in vitro, and supplementation, in vivo, both demonstrate a potential for improvements in mitochondrial metabolism and biogenesis, and even for potentiating the adaptive effects of endurance exercise. Mechanistically, lactate may be an important molecule in explaining the aforementioned positive effects of FO.

Analysis of the Microbial Diversity and Characteristics of Fermented Blueberry Beverages from Different Regions

In this study, high-throughput sequencing methods were used to analyze the composition and diversity of the microbial communities of three different traditional fermented blueberry beverages (Jiaosu A, Jiaosu B, and Jiaosu C) produced in three different regions. Lactic acid bacteria and yeast counts, total soluble solids, total titration acid, total phenols, total flavonoids, total anthocyanin, superoxide dismutase, and antioxidant activity were analyzed in all samples. The results showed that at the phylum level, the bacteria in all samples were predominantly Firmicutes and Proteobacteria, while the majority of fungus belonged to Ascomycota. At the genus level, Lactobacillus, Gluconobacter, and Acetobacter were the dominant bacteria, and Dekkera and Issatchenkia were the dominant fungi. Our data show that the lactic acid bacteria counts in Jiaosu A were the lowest of the three products, in the range of 4.31–10.9 log CFU/mL, while yeast counts ranged from 6.71 to 7.35 log CFU/mL. The antioxidant activities of Jiaosu C were greater than those of Jiaosu A and Jiaosu B, and Spearman correlation analysis showed that the relative abundance of Lactobacillus and Dekkera was significantly positively correlated with total phenolics, total anthocyanin, total flavonoids, and antioxidant index.

Effect of adzuki bean sprout fermented milk enriched in γ-aminobutyric acid on mild depression in a mouse model

This study focused on the ability of adzuki bean (Vigna angularis) sprout fermented milk, which is rich in γ-aminobutyric acid (GABA), to relieve anxiety and mild depression. A high-yield GABA-producing strain, Lactobacillus brevis J1, from a healthy cow was screened, and its physiological and probiotic properties were evaluated. The effect of adzuki bean sprout fermented milk was investigated in vivo in a chronic depression mouse model. The results showed that Lb. brevis J1 had excellent probiotic properties, grew well at low pH and 3% NaCl, and adhered to the surface of HT-29 cells. The GABA-enriched (241.30 ± 1.62 µg/mL) adzuki bean sprout fermented milk prepared with Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus plantarum, and Lb. brevis J1 can reduce and possibly prevent mild depression-like symptoms in mice (C57/B6) by increasing social interaction and enhancing the pleasure derived from movement. The research revealed that the GABA_B-cyclic AMP-protein kinase A-cAMP-response element binding protein (GABA_B-cAMP-PKA-CREB) signaling pathway was related to the depression-like symptoms and that levels of 5-hydroxytryptamine, norepinephrine, and dopamine in the hippocampus of mice increased after treatment with the adzuki bean sprout fermented milk. Our results suggest that GABA-enriched dairy products have the potential to prevent or treat mild depression-like symptoms in mice, which suggests a new approach for a dietary therapy to treat chronic social stress.

Characterization of Aspergillus niger MK981235 xylanase with extraction of anti-hepatotoxic, antioxidant, hypocholesterolemic and prebiotic Corchorus olitorius stems xylooligosaccharides

The object of this study was to utilize agro-industrial waste Corchorus olitorius stems (molokhia stems, MS) as substrate, for Aspergillus niger MK981235 xylanase production and as source of biologically active xylooligosaccharides (XOS). This study succeeded in utilization of Aspergillus niger MK981235 xylanase under different saccharification conditions designed by central composite design (CCD) for extraction of 15 biologically active XOS (anti-hepatotoxic, antioxidant, hypocholesterolemic and prebiotic) with different monosaccharides constituents composition and percent. A. niger MK981235 xylanase showed the highest activity 6.60 U·ml^-1 at 50 °C with 1.5% xylan. The kinetics included K_m and V_max were determined to be 6.67 mg·ml^-1 and 20 μmol·ml^-1·min^-1, respectively. Moreover, A. niger MK981235 xylanase thermodynamics E_a (activation energy) and E_d (activation energy of denaturation) were determined to be 21.95 and 39.51 KJ·mol^-1, respectively. The highest prebiotic effect (growth promation) was exerted by the central MS XOS on Lactobacillus plantarum and Lactobacillus rhamnosus (125 and 135.3%, respectively). Also, the central MS XOS, exerted the highest cholesterol reduction and antioxidant activities 74.7 and 92%, respectively, showed remarkable in vivo protective role against the hepatic toxicity of lithium carbonate evaluated by changes in body weight, liver function markers (AST, ALT, Alb, total bilirubin) and tissue makers (MDA and GSH).

Gamma Aminobutyric Acid-Enriched Fermented Oyster (Crassostrea gigas) Increases the Length of the Growth Plate on the Proximal Tibia Bone in Sprague-Dawley Rats

Bone growth during childhood and puberty determines an adult’s final stature. Although several prior studies have reported that fermented oyster (FO) consisting of a high amount of gamma aminobutyric acid can be attributed to bone health, there is no research on the efficacy of FO on growth regulation and the proximal tibial growth plate. Therefore, in this study, we investigated the effect of FO oral administration on hepatic and serum growth regulator levels and the development of the proximal tibial growth plate in young Sprague-Dawley rats. Both oral administration of FO (FO 100, 100 mg/kg FO and FO 200, 200 mg/kg FO) and subcutaneous injection of recombinant human growth hormone (rhGH, 200 μg/kg of rhGH) for two weeks showed no toxicity. Circulating levels of growth hormone (GH) significantly increased in the FO 200 group. The expression and secretion of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) were enhanced by FO administration. FO administration promoted the expression of bone morphogenic proteins IGF-1 and IGFBP-3 in the proximal tibial growth plate. This positive effect of FO resulted in incremental growth of the entire plate length by expanding the proliferating and hypertrophic zones in the proximal tibial growth plate. Collectively, our results suggested that oral administration of FO is beneficial for bone health, which may ultimately result in increased height.

Probiotics and Psychobiotics: the Role of Microbial Neurochemicals

In light of recent data, microorganisms should be construed as organisms that are capable of communication and collective behaviors. Microbial communication signals are involved both in interactions among microbial cells within microbial social systems, including the human body-inhabiting microconsortium, and the dialog between the microbiota and the host organism. The microbiota inhabits various niches of the host organism, especially the gastrointestinal (GI) tract. Microorganisms release diverse signal molecules and, in addition, specifically respond to host signals. This enables them to constantly interact with the nervous system including the brain and the immune system of the host organism. Evolutionarily conserved signals that are involved in the communication between microbiota and the host include neuroactive substances (neurochemicals) such as peptides, amino acids, biogenic amines, short-chain fatty acids, and gaseous substances. This ongoing dialog may either stabilize the host's physical and mental health state or, alternatively, cause serious health problems. Attempts are made to correct imbalances in the brain-gut-microbiota axis with probiotics including their subgroup called psychobiotics that release neuroactive substances directly influencing the human brain, psyche, and behavior. A number of recent review works address the microbiota-host system and its communication signals. Some of the publications focus on the involvement of neurochemicals in the bidirectional communication within the host-microbiota system. However, this work concentrates on the impact of bacterial cell components, metabolites, and signal molecules as promising alternatives to the currently widespread probiotics that have both advantages and disadvantages. Such biologically active agents of microbial origin are referred to as postbiotics or, alternatively, metabiotics (the term preferred in this work).

Protective Mechanism of Common Buckwheat (Fagopyrum esculentum Moench.) against Nonalcoholic Fatty Liver Disease Associated with Dyslipidemia in Mice Fed a High-Fat and High-Cholesterol Diet

This study aimed to investigate the protective mechanism of common buckwheat (Fagopyrum esculentum Moench.) against nonalcoholic fatty liver disease (NAFLD) associated with dyslipidemia in mice that were fed a high-fat and high-cholesterol diet (HFD). Results showed that oral supplementation of common buckwheat significantly improved physiological indexes and biochemical parameters related to dyslipidemia and NAFLD in mice fed with HFD. Furthermore, the HFD-induced reductions in fecal short-chain fatty acids were reversed by common buckwheat intervention, which also increased the fecal bile acid (BA) abundance compared with HFD-induced hyperlipidemic mice. Liver metabolomics based on ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry demonstrated that common buckwheat supplementation made significant regulatory effects on the pentose phosphate pathway, starch and sucrose metabolism, primary BA biosynthesis, and so forth. The results of high-throughput sequencing revealed that common buckwheat supplementation significantly altered the structure of the intestinal microbiota in mice fed with HFD. The correlations between lipid metabolic parameters and intestinal microbial phylotypes were also revealed by the heatmap and network. Additionally, common buckwheat intervention regulated the mRNA expressions of genes responsible for liver lipid metabolism and BA homeostasis, thus promoting BA synthesis and excretion. These findings confirmed that common buckwheat has the outstanding ability of improving lipid metabolism and could be used as a potential functional food for the prevention of NAFLD and hyperlipidemia.

Isolation, Identification, and Optimization of γ-Aminobutyric Acid (GABA)-Producing Bacillus cereus Strain KBC from a Commercial Soy Sauce moromi in Submerged-Liquid Fermentation

A new high γ-aminobutyric acid (GABA) producing strain of Bacillus cereus was successfully isolated from soy sauce moromi. This B. cereus strain named KBC shared similar morphological characteristics (Gram-positive, rod-shaped) with the reference B. cereus. 16S rRNA sequence of B. cereus KBC was found to be 99% similar with B. cereus strain OPWW1 under phylogenetic tree analysis. B. cereus KBC cultivated in unoptimized conditions using De Man, Rogosa, Sharpe (MRS) broth was capable of producing 523.74 mg L−1 of GABA within five days of the cultivation period. By using response surface methodology (RSM), pH level, monosodium glutamate (MSG) concentration and temperature were optimized for a high concentration of GABA production. The pH level significantly influenced the GABA production by B. cereus KBC with p-value = 0.0023. GABA production by B. cereus KBC under the optimized condition of pH 7, MSG concentration of 5 g L−1 and temperature of 40 °C resulted in GABA production of 3393.02 mg L−1, which is 6.37-fold higher than under unoptimized conditions. Overall, this study has shown that B. cereus KBC isolated from soy sauce moromi is capable of producing a high concentration of GABA together with the optimal fermentation conditions that have been statistically analysed using RSM.

Effect of fermented oyster extract on growth promotion in Sprague-Dawley rats

Background

Oysters (Crassostrea gigas) are a popular marine product worldwide and have the advantage of nutritional benefits. This study aimed to investigate the effect of fermented oyster extract (FO) on growth promotion, including analysis of body size, bone microarchitecture, hematology and biochemistry in vivo.

Methods

The amount of nutrients and gamma aminobutyric acid (GABA) were determined. Sprague–Dawley rats were randomly divided into four groups: the control group, FO 50 group (FO 50 mg/kg), and FO 100 group (FO 100 mg/kg) were administered orally once daily and the recombinant human growth hormone (rhGH) group (200 μg/kg) was intraperitoneally injected once daily for 14 days.

Results

Oral administration of FO 100 significantly increased body length and had no effect on organ damage or hematological profiles. However, administration of rhGH significantly induced hypertrophy of the liver, kidney and spleen along with a marked increase in body length. Tibia length and the growth plate were increased, and bone morphometric parameters were slightly improved by FO and rhGH administration. Serum analysis showed that the levels of GH and insulin like growth factor-1 (IGF-1) were slightly upregulated by FO administration. Nevertheless, the protein expression of hepatic IGF-1 was markedly increased by FO 100 and rhGH administration.

Conclusions

FO have high content of GABA, and induced positive effects on body length, tibial length, growth-plate length and hepatic IGF-1 synthesis in SD rats with no toxicity or alterations of hematological profile. Therefore, these results suggest that GABA-enriched FO could be considered a potential alternative treatment for growth stimulation.

Characteristics of Planococcus antioxidans sp. nov., an antioxidant-producing strain isolated from the desert soil in the Qinghai-Tibetan Plateau

Strain Y74^T was an isolate from the sandy soil in the town of Huatugou, Qinghai-Tibet Plateau, China. An analysis of this strain's phenotypic, chemotaxonomic, and genomic characteristics established the relationship of the isolate with the genus Planococcus. Strain Y74^T was able to grow between 4 and 42°C (with an optimum temperature of 28°C) at pH values of 6-8.5 and in 0%-7% (w/v) NaCl. The dominant quinones were MK-8 and MK-7. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and an unknown phospholipid. The majority of the fatty acid content was anteiso-C_15:0 (28.8%) followed by C_16:1 ω7c alcohol (20.9%) and iso-C_14:0 (13.4%). The 16S rRNA gene sequence similarity analysis demonstrated a stable branch formed by strain Y74^T and Planococcus halotolerans SCU63^T (99.66%). The digital DNA-DNA hybridization between these two strains was 57.2%. The G + C content in the DNA of Y74^T was 44.5 mol%. In addition, the morphological, physiological, and chemotaxonomic pattern clearly differentiated the isolates from their known relatives. In conclusion, the strain Y74^T (=JCM 32826^T  = CICC24461^T ) represents a novel member of the genus Planococcus, for which the name Planococcus antioxidans sp. nov. is proposed. Strain Y74^T was found to have potent antioxidant activity via its hydrogen peroxide tolerance and its 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. The DPPH radical-scavenging activity was determined to be 40.2 ± 0.7%. The genomic analysis indicated that six peroxidases genes, one superoxide dismutase gene, and one dprA (DNA-protecting protein) are present in the genome of Y74^T .

Probiotic potential of lyophilized Lactobacillus plantarum GP

Purpose

Freeze drying of Lactobacillus plantarum GP in the presence of wall materials to achieve improved survival and retention of probiotic functionality during storage.

Methods

L. plantarum cells were lyophilized in the presence of inulin, fructooligosaccharides, lactulose, and/or skim milk. The lyophilized vials were stored at 8–10 °C up to 6 months and cells from these vials were evaluated for their probiotic functionality.

Results

L. plantarum GP freeze dried in the presence of wall material lactulose displayed viability of 98 ± 2.8% promising survival rate in the stress conditions of human digestive tract. The freeze dried cells of Lactobacilli retained the ability to adhere intestinal mucin layer, form biofilm, inhibit food spoilage and enteropathogens, produce β-galactosidase, bile salt hydrolase and γ-amino butyric acid, remove cholesterol, and scavenge DPPH radical.

Conclusion

Lyophilized cells of L. plantarum GP retained all the functional characteristics without any significant loss during storage, which prompts to incorporate prebiotics for the development of stable functional food products.

Influence of Lactobacillus brevis on metabolite changes in bacteria-fermented sufu

Sufu is a form of food derived from traditional Chinese fermented soybean. It has a unique flavor and contains abundant nutrients. With demands for healthy food on the rise, a higher level of sufu functionality is required. In fermentation of soybean-derived products, lactic acid bacteria (LAB) are widely used as an adjunct culture, which provides health benefits and enhances flavor of food. Among LAB, Lactobacillus brevis has the potential to generate γ-aminobutyric acid (GABA), which is well-known for its physiological functions. In this study, L. brevis was added to bacteria-fermented sufu to evaluate its impacts on sufu quality. Sufu was produced via co-inoculation with Bacillus subtilis and L. brevis (group A sufu) or a single inoculation with B. subtilis (group B sufu). Metabolite changes in the two groups during fermentation were investigated and physicochemical changes were observed. The results indicated that the addition of L. brevis increased the concentration of GABA and decreased the concentrations of histamine and serotonin. The concentrations of volatile compounds, such as esters and acids, especially 2-methyl-butanoic acid ethyl ester, as well as the concentrations of phenylethyl alcohol and 3-methyl-butanol were significantly higher in group A. Inoculation of L. brevis changed the metabolite profile of sufu and improved its functionality and safety of edibility. The current study explored the potential of applying L. brevis to the manufacture of bacteria-fermented sufu.

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.

An Updated Review on Pharmaceutical Properties of Gamma-Aminobutyric Acid

Gamma-aminobutyric acid (Gaba) is a non-proteinogenic amino acid that is widely present in microorganisms, plants, and vertebrates. So far, Gaba is well known as a main inhibitory neurotransmitter in the central nervous system. Its physiological roles are related to the modulation of synaptic transmission, the promotion of neuronal development and relaxation, and the prevention of sleeplessness and depression. Besides, various pharmaceutical properties of Gaba on non-neuronal peripheral tissues and organs were also reported due to anti-hypertension, anti-diabetes, anti-cancer, antioxidant, anti-inflammation, anti-microbial, anti-allergy, hepato-protection, reno-protection, and intestinal protection. Therefore, Gaba may be considered as potential alternative therapeutics for prevention and treatment of various diseases. Accordingly, this updated review was mainly focused to describe the pharmaceutical properties of Gaba as well as emphasize its important role regarding human health.

Health promoting activities of probiotics

In recent years, probiotics have received increasing attention and become one type of popular functional food because of their many biological functions. Among these desirable biological functions, the immune regulation, antioxidative activities, and antimicrobial effects are essential properties to maintain host health. Probiotics can regulate the immune system and improve the antioxidative system by producing microbial components and metabolites. Meanwhile, probiotics also possess antimicrobial abilities owing to their competition for nutrient requirements and mucus adherence, reducing pathogenic toxins, producing antimicrobial metabolites (short-chain fatty acids, bacteriocins, reuterin, linoleic acid, and secondary bile acids) and enhancing intestinal, or systemic immunity. Therefore, probiotics could be used to alleviate heavy metal toxicity and metabolic disorders by improving immunity, the antioxidative system, and intestinal micro-environment. This comprehensive review mainly highlights the potential health promoting activities of probiotics based on their antioxidative, antimicrobial, and immune regulatory effects. PRACTICAL APPLICATIONS: The antioxidative defense and the immune system are essential to maintain human health. However, many factors may result in microbial dysbiosis in the gut, which subsequently leads to pathogenic expansion, oxidative stress, and inflammatory responses. Therefore, it is important to explore beneficial foods to prevent or suppress these abnormal responses. Successful application of probiotics in the functional foods has attracted increasing attention due to their immune regulatory, antioxidative, and antimicrobial properties. The aim of this review is to introduce immune regulatory antioxidative and antimicrobial effects of probiotics, which provides some basic theories for scientific research and development of potential functional foods.

In vitro selection and in vivo confirmation of the antioxidant ability of Lactobacillus brevis MG000874

AIMS

This study aimed at isolating a probiotic strain from a collection of lactic acid bacteria (LAB) with the high antioxidant property and confirms its potential in d-gal-induced oxidative stress (OS) murine model.

METHODS AND RESULTS

The in vitro antioxidant ability of 16 LAB strains was determined in the cell-free supernatant of 3- to 5-day-old culture, intact cells and cell lysates using three different methods for determining the reactive oxygen species scavenging activity and inhibition of lipid peroxidation. The strain, An28, presented the best antioxidant activity and was identified as Lactobacillus brevis MG000874 on the basis of 16 sRNA gene sequencing. The antioxidant potential of L. brevis MG000874 was confirmed in an OS murine model. Albino mice were exposed to d-galactose at a dose of 150 mg kg^-1 BW and fed with L. brevis MG000874 (0·2 ml of 10¹⁰ CFU per ml cell suspension per animal per day). Antioxidant enzymes were quantified spectrophotometrically in the liver, kidney and serum. Subcutaneous administration of d-gal resulted in decrease in superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) and increase in glutathione-S-transferase (GST) levels in animals. The L. brevis MG000874-treated animals displayed improvement in SOD, CAT and GST in all tissues and GSH in the liver and serum. The safety assessment of L. brevis MG000874 was performed by comparing liver and renal function tests. None of the selected indicators was significantly different from the negative control group.

CONCLUSIONS

The antioxidant potential of 16 strains was noticed to be strain specific and in vivo performance of L. brevis MG000874 was found satisfactory in a d-gal murine model.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lactobacillus brevis MG000874 was identified for its admirable antioxidant property. This strain or/and its metabolites could be further investigated for possible applications in humans and veterinary fields.

Simultaneous Intake of Euglena gracilis and Vegetables Exerts Synergistic Anti-Obesity and Anti-Inflammatory Effects by Modulating the Gut Microbiota in Diet-Induced Obese Mice

We determined whether the anti-obesity effect provided by the consumption of Euglena gracilis (Euglena), which is rich in insoluble dietary fiber, could be enhanced by the co-consumption of vegetables with an abundance of soluble dietary fiber. Nine-week-old male C57BL/6J mice were divided into five groups as follows: group 1 received a normal diet, group 2 received a high-fat diet, and groups 3, 4, and 5 received high fat diets containing 0.3% paramylon, 1.0% Euglena, or 1.0% Euglena plus 0.3% vegetables (barley leaf, kale, and ashitaba), respectively. Mice were fed ad libitum until 18 weeks of age. Euglena intake significantly reduced visceral fat accumulation in obese mice, and co-consumption of vegetables enhanced this effect. Consumption of Euglena with vegetables reduced adipocyte area, suppressed the expression of genes related to fatty acid synthesis, upregulated genes related to adipocyte lipolysis, and suppressed serum markers of inflammation. Notably, we also observed an increase in the fraction of short-chain fatty acid-producing beneficial bacteria, a reduction in harmful bacteria that cause inflammation, and an increase in short-chain fatty acid production. Therefore, the co-consumption of vegetables enhanced the anti-obesity and anti-inflammatory effects of Euglena, likely by modulating the gut microbiota composition.

Optimized cultural conditions of functional yogurt for γ-aminobutyric acid augmentation using response surface methodology

Yogurt, a functional dairy food product, is an effective medium for delivering beneficial functional ingredients. One ingredient, γ-aminobutyric acid (GABA), has growing appeal in the development of functional foods for its potential in reducing the risk of diabetes, hypertension, and stress as a bioactive agent. However, the concentration of GABA in existing food products is remarkably low. We developed a functional yogurt rich in GABA using Streptococcus thermophilus fmb5. The GABA yield of yogurt was enhanced by optimization of culture conditions using single factor and response surface methods. The results showed that culture temperature, monosodium glutamate concentration, and culture time are the 3 main factors that affect GABA yield. The optimal culture conditions were determined as follows: 38.8°C for culture temperature, 20 g/L of monosodium glutamate, and 120 h of culture time. Under the above optimal conditions, the actual yield of GABA production was maximized at 9.66 g/L, which was 1.2 times or higher than that of from any single factor treatment. The GABA concentration, viable bacteria number, and water-holding capacity of GABA-rich yogurt were stable throughout the whole storage time. The results show that producing yogurt with Streptococcus thermophilus fmb5 and the optimized culture conditions will achieve high GABA concentrations that maximize health benefits to consumers.

Simultaneous Intake of Euglena Gracilis and Vegetables Synergistically Exerts an Anti-Inflammatory Effect and Attenuates Visceral Fat Accumulation by Affecting Gut Microbiota in Mice

We determined whether the benefits provided by the consumption of Euglena gracilis (Euglena), which is a unicellular photosynthesizing green alga and rich in insoluble dietary fiber paramylon, can be enhanced by the co-consumption of vegetables that are rich in soluble dietary fiber. Nine-week-old male C57BL/6J mice were divided into four groups: group 1 received normal diet, whereas groups 2, 3 and 4 received normal diet containing 0.3% paramylon, 1.0% Euglena, or 1.0% Euglena plus 0.3% vegetables (barley leaf, kale and ashitaba), respectively. Mice were fed ad libitum until 18 weeks of age. Euglena intake significantly decreased serum markers of inflammation and co-consumption of vegetables enhanced this reduction. Notably, we observed an increase in the fraction of beneficial bacteria producing short-chain fatty acids, a reduction in harmful bacteria that cause inflammation and an increase in short-chain fatty acid production. Visceral fat accumulation was also reduced. Subsequent analyses showed that co-consumption of Euglena with vegetables reduced adipocyte area, suppressed the expression of genes related to fatty acid synthesis and increased the expression of genes related to adipocyte growth and lipolysis. Therefore, co-consumption of Euglena with vegetables enhanced its anti-inflammatory effect and the inhibitory effect on visceral fat accumulation likely by modulating the composition of gut microbiota.

Production of γ-aminobutyric acid in Escherichia coli by engineering MSG pathway

The compound γ-aminobutyric acid (GABA) has many important physiological functions. The effect of glutamate decarboxylases and the glutamate/GABA antiporter on GABA production was investigated in Escherichia coli. Three genes, gadA, gadB, and gadC were cloned and ligated alone or in combination into the plasmid pET32a. The constructed plasmids were transformed into Escherichia coli BL21(DE3). Three strains, E. coli BL21(DE3)/pET32a-gadA, E. coli BL21(DE3)/pET32a-gadAB and E. coli BL21(DE3)/pET32a-gadABC were selected and identified. The respective titers of GABA from the three strains grown in shake flasks were 1.25, 2.31, and 3.98 g/L. The optimal titer of the substrate and the optimal pH for GABA production were 40 g/L and 4.2, respectively. The highest titer of GABA was 23.6 g/L at 36 h in batch fermentation and was 31.3 g/L at 57 h in fed-batch fermentation. This study lays a foundation for the development and use of GABA.

Phenolic profile, free amino acids composition and antioxidant potential of dried longan fermented by lactic acid bacteria

In this study, dried longan pulp (DLP) was subjected to fermentation using selected strains of lactic acid bacteria (Lactobacillus plantarum subsp. Plantarum and Leuconostoc mesenteroides). We then studied changes in the free and bound phytochemical profile, antioxidant activity, free amino acid, and organic acid composition. Fermentation exhibited a 17.4% and 5.7% increase in the amount of free and total phenolic contents of DLP. Phenolic composition determined by HPLC revealed significant changes due to fermentation that were primarily in the contents of gallic acid, vanillic acid, 4-methylcatechol and p-coumaric acid, resulting in a 37.9% and 25.7% increase in free gallic acid and 4-methylcatechol, respectively. Fermentation was also found to enhance the ferric reducing antioxidant power of both free and total and the oxygen radical absorbance capacity of free phenolic fraction by 18.3%, 11.8%, and 37.4%, respectively. In addition, fermentation was observed to reduce the contents of free amino acids with bitter taste (phenylalanine, tyrosine and leucine), and increase amino acids (taurine, aspartic acid, cysteine, cysteine thiazoline and γ-amino-butyric acid) having antioxidant potential. Therefore, this study provides basis for the production of fermented longan-based functional products with improved antioxidant activity.

Role of Neurochemicals in the Interaction between the Microbiota and the Immune and the Nervous System of the Host Organism

This work is concerned with the role of evolutionary conserved substances, neurotransmitters, and neurohormones, within the complex framework of the microbial consortium-immune system-nervous system axis in the human or animal organism. Although the operation of each of these systems per se is relatively well understood, their combined effects on the host organism still await further research. Drawing on recent research on host-produced and microbial low-molecular-weight neurochemicals such as biogenic amines, amino acids, and short-chain fatty acids (SCFAs), we suggest that these mediators form a part of a universal neurochemical "language." It mediates the whole gamut of harmonious and disharmonious interactions between (a) the intestinal microbial consortium, (b) local and systemic immune cells, and (c) the central and peripheral nervous system. Importantly, the ongoing microbiota-host interactivity is bidirectional. We present evidence that a large number of microbially produced low-molecular-weight compounds are identical or homologous to mediators that are synthesized by immune or nervous cells and, therefore, can bind to the corresponding host receptors. In addition, microbial cells specifically respond to host-produced neuromediators/neurohormones because they have adapted to them during the course of many millions of years of microbiota-host coevolution. We emphasize that the terms "microbiota" and "microbial consortium" are to be used in the broadest sense, so as to include, apart from bacteria, also eukaryotic microorganisms. These are exemplified by the mycobiota whose role in the microbial consortium-immune system-nervous system axis researchers are only beginning to elucidate. In light of the above, it is imperative to reform the current strategies of using probiotic microorganisms and their metabolites for treating and preventing dysbiosis-related diseases. The review demonstrates, in the example of novel probiotics (psychobiotics), that many target-oriented probiotic preparations produce important side effects on a wide variety of processes in the host organism. In particular, we should take into account probiotics' capacity to produce mediators that can considerably modify the operation of the microecological, immune, and nervous system of the human organism.

The Effects of Fermented Laminaria japonica on Short-Term Working Memory and Physical Fitness in the Elderly

Considering the neuroprotective and antioxidant potential of fermented Laminaria japonica A. (FST), the purpose of the present study is to establish whether FST may be considered a viable, efficacious supplement that can be administered in later life to offset neurodegenerative conditions associated with aging. Forty senior subjects participated in a randomized, double-blind, and placebo-controlled study. Two groups were formed, one FST group (n = 32, 72.35 ± 5.54 yrs) and one placebo (CON) (n = 28, 74.57 ± 5.69 yrs), which received 1.5 g/day of FST for 6 weeks. Subjects were asked to abstain from any regular exercise. In order to analyze short-term memory, a variety of neuropsychological tests were implemented. Body composition, physical fitness evaluations, antioxidant function, and inflammatory markers were also included in the analyses pre- and posttest. We demonstrated that FST significantly improved neuropsychological test scores, including higher scores in the K-MMSE, numerical memory test, Raven test, and iconic memory, compared to the CON group. Shorter test trial times in the 6-meter [corrected] walk test were observed in the FST group (p<0.001 and p<0.05, trials 1 and 2, respectively). FST also significantly increased antioxidant activity of GPx, GSR, and SOD, reduced the production of TBARS, and lowered 8-oxoDG levels. The present study highlights the potential widespread application of FST in protecting against the degenerative effects of aging on short-term memory and physical function. Neuropsychological evaluation indicates that FST may provide a protective mechanism against cognitive impairment associated with dementia. Neuromuscular integrity and physical function are typically compromised in aging and dementia patients; thus, whether by stimulation of muscle-related growth factors or an increase in serum BDNF, FST supplementation may act to preserve physical function in the elderly. The bioactive constituents of FST such as GABA and fucoidan acting to provide improvements in antioxidant activity following FST supplementation may protect against progressive degeneration purportedly caused by reactive oxygen species.

Comparison of volatile and non-volatile metabolites in rice wine fermented by Koji inoculated with Saccharomycopsis fibuligera and Aspergillus oryzae

This study investigated volatile and nonvolatile metabolite profiles of makgeolli (a traditional rice wine in Korea) fermented by koji inoculated with Saccharomycopsis fibuligera and/or Aspergillus oryzae. The enzyme activities in koji were also examined to determine their effects on the formation of metabolites. The contents of all 18 amino acids detected were the highest in makgeolli fermented by S. fibuligera CN2601-09, and increased after combining with A. oryzae CN1102-08, unlike the contents of most fatty acids. On the other hand, major volatile metabolites were fusel alcohols, acetate esters, and ethyl esters. The contents of most fusel alcohols and acetate esters were the highest in makgeolli fermented by S. fibuligera CN2601-09, for which the protease activity was the highest, leading to the largest amounts of amino acods. The makgeolli samples fermented only by koji inoculated with S. fibuligera could be discriminated on PCA plots from the makgeolli samples fermented in combination with A. oryzae. In the case of nonvolatile metabolites, all amino acids and some metabolites such as xylose, 2-methylbenzoic acid, and oxalic acid contributed mainly to the characteristics of makgeolli fermented by koji inoculated with S. fibuligera and A. oryzae. These results showed that the formations of volatile and nonvolatile metabolites in makgeolli can be significantly affected by microbial strains with different enzyme activities in koji. To our knowledge, this study is the first report on the effects of S. fibuligera strains on the formation of volatile and non-volatile metabolites in rice wine, facilitating their use in brewing rice wine.

High γ-aminobutyric acid production from lactic acid bacteria: Emphasis on Lactobacillus brevis as a functional dairy starter

γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.

Effects of Prebiotics on Antioxidant Activity of Goat Milk Fermented by Lactobacillus plantarum L60

The production of functional fermented goat milk with synbiotic have attracted widespread attention recently with the purpose of promoting health. The aim of present study was to investigate the effects of several prebiotics (inulin, fructo-oligosaccharide, galacto-oligosaccharide and xylo-oligosaccharide) on antioxidant activity and promote the development of functional goat milk. All the prebiotics exhibited the potential of enhancing the antioxidant activity of fermented goat milk, especially inulin and fructo-oligosaccharide showed better promotive effects. The optimum additions of inulin, xylo-oligosaccharide, galacto-oligosaccharide and fructo-oligosaccharide obtained were 0.6%, 0.6%, 0.6% and 0.4%, respectively. The DPPH radical scavenging rates reached to 75.52%, 74.12%, 69.41%, 80.28%, respectively, and the scavenging rates of superoxide radical were 21.09%, 18.20%, 27.61% and 29.92%, respectively, which were all higher than the control. This paper provides theoretical basis for the development of the functional goat milk.

Antioxidant activity of JM113 in vitro and its protective effect on broiler chickens challenged with deoxynivalenol

The aim of this experiment was to study the antioxidant capacity of JM113 isolated from healthy intestinal contents of Tibetan chicken and its protective effect on broiler chickens challenged with deoxynivalenol (DON). Compared with PZ01 and M23, JM113 demonstrated maximum reducing ( < 0.05) activity and resistance in the presence of 1.2 mmol/L hydrogen peroxide, and great scavenging ability ( < 0.05) against hydroxyl, superoxide anion, and 1,1-diphenyl-2-picrylhydrazyl radicals in vitro. For each strain, the antioxidant activities of live bacterial strains were greater ( < 0.05) than of cell free extracts and dead bacterial strains. To examine the antioxidant capacity of JM113 in vivo, 192 1-d-old Arbor Acres chicks were randomly divided into 4 treatments groups consisting of 6 replicates with 8 birds per replicate. The dietary treatments were 1) control; 2) control diet supplemented with JM113 at 1 × 10 cfu/kg; 3) control diet contaminated with DON at 10 mg/kg; 4) control diet contaminated with DON at 10 mg/kg and supplemented with JM113 at 1 × 10 cfu/kg. Dietary supplementation with DON decreased ( < 0.05) superoxide dismutase activity in serum and increased ( < 0.05) malondialdehyde in the jejunal mucosa of broilers, compared to the control. However, supplementation with JM113 to both the DON-contaminated diet and the control diet, caused a significant reduction ( < 0.05) in malondialdehyde activity in the jejunal mucosa. A reduction ( < 0.05) in expression of nuclear factor erythroid 2-related factor 2 was observed in the jejunal mucosa of broilers fed dietary supplementation with DON, whereas the mRNA levels of and its corresponding downstream gene increased ( < 0.05) with JM113 treatment. Addition of JM113 resulted in longer villi ( < 0.05), even in combination with DON compared to the DON group. JM113 treatment, especially in the DON plus JM113 group, up-regulated ( < 0.05) the expression of mRNA. In conclusion, the present study demonstrates that the JM113 strain has great antioxidant activity and supplementation in feed protected the integrity of the intestinal barrier in broilers challenged with DON, suggesting its use for alleviation of negative effects of DON in poultry.

Chemical characterization and antioxidant potential of volatile oil from an edible seaweed Porphyra tenera (Kjellman, 1897)

Background

Porphyra tenera (Kjellman, 1897) is the most common eatable red seaweed in Asia. In the present study, P. tenera volatile oil (PTVO) was extracted from dried P. tenera sheets that were used as food by the microwave hydrodistillation procedure, after which the characterization of its chemical constituents was done by gas chromatography and mass spectroscopy and its antioxidant potential was evaluated by a number of in vitro biochemical assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, nitric oxide (NO) scavenging, superoxide radical scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, hydroxyl radical scavenging and reducing power assay and inhibition of lipid peroxidation.

Results

A total of 30 volatile compounds comprising about 99.4% of the total volume were identified, of which trans-beta-ionone (20.9%), hexadecanoic acid (9.2%) and 2,6-nonadienal (8.7%) were present in higher quantities. PTVO exhibited strong free radical scavenging activity by DPPH scavenging (44.62%), NO scavenging (28.45%) and superoxide scavenging (54.27%) at 500 µg/mL. Similarly, it displayed strong ABTS radical scavenging (IC₅₀ value of 177.83 µg/mL), hydroxyl radical scavenging (IC₅₀ value of 109.70 µg/mL), and moderate lipid peroxidation inhibition activity (IC₅₀ value of 231.80 µg/mL) and reducing power (IC_0.5 value of 126.58 µg/mL). PTVO exhibited strong antioxidant potential in a concentration dependent manner and the results were comparable with the BHT and α-tocopherol, taken as the reference standard compounds (positive controls).

Conclusions

Taken together, PTVO with potential bioactive chemical compounds and strong antioxidant activity could be utilized in the cosmetic industries for making antioxidant rich anti-aging and sun-screen lotion and in the food sector industries as food additives and preservatives.

Biotechnological advances and perspectives of gamma-aminobutyric acid production

Gamma-aminobutyric acid (GABA) is a four-carbon non-protein amino acid that is widely distributed among various organisms. Since GABA has several well-known physiological functions, such as mediating neurotransmission and hypotensive activity, as well as having tranquilizer effects, it is commonly used as a bioactive compound in the food, pharmaceutical and feed industries. The major pathway of GABA biosynthesis is the irreversible decarboxylation of L-glutamate catalyzed by glutamate decarboxylase (GAD), which develops a safe, sustainable and environmentally friendly alternative in comparison with traditional chemical synthesis methods. To date, several microorganisms have been successfully engineered for high-level GABA biosynthesis by overexpressing exogenous GADs. However, the activity of almost all reported microbial GADs sharply decreases at physiological near-neutral pH, which in turn provokes negative effects on the application of these GADs in the recombinant strains for GABA production. Therefore, ongoing efforts in the molecular evolution of GADs, in combination with high-throughput screening and metabolic engineering of particular producer strains, offer fascinating new prospects for effective, environmentally friendly and economically viable GABA biosynthesis. In this review, we briefly introduce the applications in which GABA is used, and summarize the most important methods associated with GABA production. The major achievements and present challenges in the biotechnological synthesis of GABA, focusing on screening and enzyme engineering of GADs, as well as metabolic engineering strategy for one-step GABA biosynthesis, will be extensively discussed.

Physicochemical, antioxidant and biocompatible properties of chondroitin sulphate isolated from chicken keel bone for potential biomedical applications

Chicken keel bone cartilage was explored for cheaper and sustainable source for isolation of chondroitin sulphate (CS) for its future use in tissue engineering and pharmaceutical industry. HPSEC analysis displayed two peaks of 100kDa for CS-keel polysaccharide and 1kDa for protein. DLS analysis of CS-keel displayed polydispersity. CS-keel yield was 15% and 53±5% uronic acid content. The quantified percentages of UA-GalNAc4S and UA-GalNAc6S disaccharide in CS-keel were 58% and 42%, respectively. FT-IR identified CS-keel to be chondroitin 4-sulphate. ¹H NMR of CS-keel confirmed the presence of N-acetylgalactosamine and Glucuronic acid. FESEM demonstrated layer structure and AFM displayed the size of CS-keel fibres. DSC, TGA and DTG studies of CS-keel showed T_d at 243°C. In vitro cell proliferation assay and morphological analysis of mouse fibroblast L929 cell lines confirmed the biocompatibility of CS-keel. CS-keel (5mg/ml) exhibited ∼49% antioxidant activity against DPPH and 22% against superoxide radical protecting from oxidative damage. CS-keel demonstrated better (70.3%) emulsifying activity than commercial sodium alginate (60.2%).