Efecto inhibidor de Lactobacillus aislado de la cavidad oral contra patógenos bacterianos y su efecto en la promoción de la salud

Aims: To determine the inhibitory effect of oral Lactobacillus against bacterial pathogens and investigate correlation between presence of Lactobacillus strains and health promotion. Method: One hundred saliva samples were collected from oral cavity of domestic dairy consumers and were investigated for the isolation and identification of Lactobacillus strain by conventional culture and sequencing of 16SrRNA. Furthermore, well diffusion assay was performed to determination of antibacterial activity of Lactobacillus strains against bacterial pathogens including Salmonella typhimurium, Klebsiella pneumoniae, Shigella sonnei, Shigella dysenteriae, Enterococcus faecalis and Enterococcus faecium. Finally, association between health condition and isolation of Lactobacillus were investigated and obtained data using questionary form were analysed by chi-square test. Results: Thirty Lactobacillus strains recovered from 100 hundred saliva samples. The most common isolated strain was L. gasseri (n=18) and followed by L. vaginalis (n=3) and L. salivarius (n=3). All Lactobacillus strains demonstrated antibacterial activity against at least one of the investigated pathogens. However, the strongest results were obtained by L. vaginalis against K. pneumonia. The correlation between the presence of thirty Lactobacillus strains and health promotion not found. However, only L. gasseri species has significant positive impact on health in their hosts (P < 0.05). Conclusion: Only some Lactobacillus species have a positive impact on health promotion. Despite of weak activity against the investigated pathogens, L. gasseri has a positive impact on the mental problem (intense anger and depression) of their hosts.Objetivos: Determinar el efecto inhibidor del Lactobacillus aislado de la cavidad oral contra patógenos bacterianos e investigar la correlación entre la presencia de cepas de Lactobacillus y la promoción de la salud. Método: se recolectaron cien muestras de saliva de la cavidad oral de consumidores de productos lácteos y se investigó el aislamiento e identificación de la cepa de Lactobacillus mediante cultivo convencional y secuenciación de 16SrRNA. Además, se realizó un ensayo de difusión en pocillos para determinar la actividad antibacteriana de las cepas de Lactobacillus contra patógenos bacterianos que incluyen Salmonella typhimurium, Klebsiella pneumoniae, Shigella sonnei, Shigella dysenteriae, Enterococcus faecalis y Enterococcus faecium. Finalmente, se investigó la asociación entre el estado de salud y el aislamiento de Lactobacillus y se obtuvieron los datos utilizando el cuestionario mediante la prueba de chi-cuadrado. Resultados: Se aislaron treinta cepas de Lactobacillus de 100 muestras de saliva. La cepa aislada más común fue L. gasseri (n = 18), seguida por L. vaginalis (n = 3) y L. salivarius (n = 3). Todas las cepas de Lactobacillus demostraron actividad antibacteriana contra al menos uno de los patógenos investigados. Sin embargo, los resultados más fuertes fueron obtenidos por L. vaginalis contra K. pneumonia. No se encontraron correlación entre la presencia de algunas de las treinta cepas de Lactobacillus y la promoción de la salud. Sin embargo, solo la especie L. gasseri tuvo un impacto positivo significativo en la salud de sus hospedadores (P <0,05). Conclusión: solo algunas especies de Lactobacillus tienen un impacto positivo en la promoción de la salud. A pesar de la actividad débil contra los patógenos investigados, L. gasseri tiene un impacto positivo en el problema mental (ira intensa y depresión) de sus huéspedes

Sucrase Activity and Exopolysaccharide Partial Characterization From Three Weissella confusa Strains

Exopolysaccharides (EPSs) produced by lactic acid bacteria have been well known for their important economic value in food, pharmaceutical and health industries. Large extracellular enzyme sucrases are used by lactic acid bacteria to polymerize EPS, i.e. fructansucrase and glucansucrase. This study aimed to characterize sucrase activity of three Weissella confusa strains MBF8-1, MBF8-2 and MBFCNC-2(1), which were isolated previously from local beverages and their EPS products as well. All strains showed ability to form mucoid and slimy colonies by visual inspection on agar plate using raffinose as substrate suggesting that they possessed fructansucrase activity besides glucansucrase. Obtained EPS products were characterized by HPLC analysis after hydrolysis using 3% TCA at 100C for 1 hour, and by viscosity as well. All strains exhibited similar peak patterns, assuming that all of them possessed fructan EPS product. Supernatant and cell pellet were also analyzed by in situ activity assay performing periodic acid Schiff staining after polyacrylamide gel electrophoresis; only cell pellet showed sucrase activity. Viscosity observation showed that EPS products from all strains were able to increase the viscosity slightly

Optimization and scale-up of fermentation of glucansucrase and branched glucan by Pediococcus pentosaceus CRAG3 using Taguchi methodology in bioreactor

The present investigation focuses on screening and optimization of media components to enhance glucansucrase and glucan production by Pediococcus pentosaceus CRAG3 at shake-flask and bioreactor level using Taguchi orthogonal array design. A three-level Taguchi orthogonal array layout of L27 (33) was employed, in which six variables were studied for their influence on glucansucrase and glucan production. The results showed that sucrose, K2HPO4 and Tween-80 were the most significant factors to improve glucansucrase production while the glucan production was mostly affected by sucrose, peptone and K2HPO4. The optimized medium composition for maximum glucansucrase and glucan production were: sucrose 3.5% and 5%; yeast extract 0.2% and 2.0%; beef extract 0.5% and 0.5%; peptone 3.0% and 1.0%; K2HPO4 0.2% and 0.2%, and Tween-80 1.0 and 0.1%, respectively. The optimized medium gave 10.1 U/ml and 10.2 U/ml glucansucrase activity while glucan concentrations were 56 mg/ml and 80 mg/ml in shake flask and bioreactor level, respectively which were in good agreement with predicted values (10.1 U/ml and 54.5 mg/ml). The optimized medium gave 2 fold enhancement in enzyme activity and 4 fold increase in glucan concentration as compared to non-optimized medium (4.5 U/ml and 15 mg/ml, respectively) at shake flask level

Dextransucrase from the mutant of Pediococcus pentosaceus (PPm) is more stable than the wild type

A comparative study on both wild type and mutant of Pediococcus pentosaceus for dextransucrase activity, its stability, dextran synthesizing activity, antibiotic sensitivity and carbohydrate utilization was performed. The wild type P. pentosaceus had specific activity of 0.58 U/mg whereas the mutant showed that of 1.0 U/mg with 72% enhancement. The antibiogram of 27 antibiotics tested against mutant showed significant differences with 9 antibiotics when compared to wild type. In carbohydrate fermentation profile, trehalose, galactose, maltose, lactose and fructose are metabolized by both the strains, but weakly in case of mutant. Stabilization of purified dextransucrase from wild type and mutant with various stabilizers was studied at 30 and 4 °C. Both enzymes were more stable at 4 °C. Among various stabilizers such as dextran (100 kDa, 10 μg/ml), glycerol (0.5%, v/v), PEG 8000 (10 μg/ml) and Tween 80 (0.5%, v/v), Tween 80 provided maximum stabilization at 4 and 30 °C. The mutant showed better stabilization than that of the wild type at both 30 and 4 °C. The loss of activity at 30 °C after 24 h in wild type and mutant in the presence of Tween 80 was only 34 and 32%, respectively, whereas the loss of activity in control of wild type and mutant was 76 and 59%, respectively. After 15 days at 4 °C, the loss of activity in control of wild type and mutant in the presence of Tween 80 was only 15 and 8%, respectively, whereas at 30 °C, the loss of activity in control of wild type and mutant was 49 and 42% respectively. Half-life of the enzyme with Tween 80 was 28.5 and 33.5 h for wild type and mutant, respectively, at 30 °C and 52.1 and 106.6 days for wild type and mutant respectively, at 4 °C

Probiotic properties of exopolysaccharide producing lactic acid bacteria isolated from vegetables and traditional Indian fermented foods

A total of 203 lactic acid bacteria (LAB) isolated from vegetables and traditional fermented food products of India such as idli batter, dhokla batter and dahi were screened for exopolysaccharide (EPS) production. Based on the amount of EPS produced, 17 LAB isolates were selected for biochemical and genetic characterization using 16S rRNA gene sequencing. The isolates were belonging to the genera Lactobacillus, Weissella and Pediococcus. In vitro examination was performed to evaluate their probiotic potential. Resistance to low pH and 0.3 % bile salts was studied. Bile salt hydrolase (BSH) activity, susceptibility to various antibiotics and antimicrobial activity against the non pathogenic E. coli K12 were also investigated. The results showed that the isolates could not grow in the presence of oxbile however some survived exposure to it for 2.5 h. Some isolates were able to grow in the presence of sodium taurocholate and showed considerable antimicrobial activity against E. coli K12. Five isolates were showing BSH activity which is reported for the genus Weissella for the first time. The results suggest that traditional fermented products could be an alternative and readily availabl

Trans-α-glucosylation of stevioside by the mutant glucansucrase enzyme Gtf180-ΔN-Q1140E improves its taste profile

The adverse health effects of sucrose overconsumption, typical for diets in developed countries, necessitate use of low-calorie sweeteners. Following approval by the European Commission (2011), steviol glycosides are increasingly used as high-intensity sweeteners in food. Stevioside is the most prevalent steviol glycoside in Stevia rebaudiana plant leaves, but it has found limited applications in food products due to its lingering bitterness. Enzymatic glucosylation is a strategy to reduce stevioside bitterness, but reported glucosylation reactions suffer from low productivities. Here we present the optimized and efficient alpha-glucosylation of stevioside using the mutant glucansucrase Gtf180-Delta N-Q1140E and sucrose as donor substrate. Structures of novel products were elucidated by NMR spectroscopy, mass spectrometry and methylation analysis; stevioside was mainly glucosylated at the steviol C-19 glucosyl moiety. Sensory analysis of the alpha-glucosylated stevioside products by a trained panel revealed a significant reduction in bitterness compared to stevioside, resulting in significant improvement of edulcorant/organoleptic properties

Biochemical characterization of two GH70 family 4,6-α-glucanotransferases with distinct product specificity from Lactobacillus aviarius subsp. aviarius DSM 20655

Nine GtfB-like 4,6-α-glucanotransferases (4,6-α-GTs) (represented by GtfX of L. aviarius subsp. aviarius DSM 20655) were identified to show distinct characteristics in conserved motifs I-IV. In particular, the "fingerprint" Tyr in motif III of these nine GtfB-type 4,6-α-GTs was found to be replaced by a Trp. In L. aviarius subsp. aviarius DSM20655, a second GtfB-like protein (GtfY), containing the canonical GtfB Tyr residue in motif III, was located directly upstream of GtfX. Biochemical characterization revealed that both GtfX and GtfY showed GtfB-like 4,6-α-GT activity, cleaving (α1→4) linkages and catalyzing the synthesis of (α1→6) linkages. Nonetheless, they differ in product specificity; GtfY only synthesizes consecutive (α1→6) linkages, yielding linear α-glucan products, but GtfX catalyzes the synthesis of (α1→6) linkages predominantly at branch points (22%) rather than in linear segments (10%). The highly branched α-glucan produced by GtfX from amylose V is resistant to digestion by α-amylase, offering great potential as dietary fibers