scholarly journals Isolation and Purification of β-Galactosidase Enzyme From Local Lactic Acid Bacteria Isolates to Overcome The Phenomenon of Non-Degradation of Milk Lactose

2021 ◽  
Vol 910 (1) ◽  
pp. 012075
Author(s):  
Aisha A. Juma ◽  
Amin S. Badawy ◽  
Sanad B. Mohammed
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Ammonium Sulfate ◽  
Gel Filtration ◽  
Streptococcus Thermophilus ◽  
Isolation And Purification ◽  
Beta Galactosidase ◽  
Mrs Medium ◽  
Sedimentation Processes ◽  
Cell Breakdown

Abstract This study aim is to purify β-galactosidase from a local isolate of yogurt in Salah al-Din Governorate to overcome the phenomenon of lactose in decomposition. The bacteria were grown on MRS medium supplemented with 1%CaCo3. Twenty isolates of lactic acid bacteria were obtained and conducting culture tests and microscopic examinations were on these isolates. In order to classify them to the level of species, it was found that there were four types, namely: Lactobacilluse acidophilus,LactobacilluseCasei,Lactobacilluse delubrici subsp.bulgaricus,Streptococcus thermophilus, The cultivation and activation steps of the different isolates were carried out forobtaining the most productive and active isolate, which is Lactobacilluse acidophiluse. Beta-galactosidase activation processes were carried out for the enzyme and cell breakdown by lysozyme. Purification and sedimentation processes were carried out using ammonium sulfate and membrane sorting, followed by gel filtration using Lactobacillus G-150. The best extraction rate (L.acidophiluse 70%) was achieved by enzyme precipitation (4,375) units/mol, and the activity increased in the membrane sorting step to (5,900) units/mol, and in gel filtration we obtained activity of the enzyme (15.591) units/mol.

scholarly journals Research note : Unsuitability of the MRS medium for the screening of hydrogen peroxide‐producing lactic acid bacteria

1997 ◽  
Vol 25 (1) ◽  
pp. 73-74 ◽  
Author(s):  
J. M. Rodríguez ◽  
M. I. Martínez ◽  
A. M. Suárez ◽  
J. M. Martínez ◽  
P. E. Hernández
Keyword(s):  
Hydrogen Peroxide ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Research Note ◽  
Mrs Medium

scholarly journals Antibacterial Activity of Some Lactic Acid Bacteria Isolated from an Algerian Dairy Product

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Abdelkader Mezaini ◽  
Nour-Eddine Chihib ◽  
Abdelkader Dilmi Bouras ◽  
Naima Nedjar-Arroume ◽  
Jean Pierre Hornez
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antibacterial Effect ◽  
Dairy Product ◽  
Streptococcus Thermophilus ◽  
Fermented Food ◽  
Bacteriocin Production ◽  
Gram Positive ◽  
Bacteria Growth ◽  
Gram Positive Bacteria

In the present study, the antibacterial effect of 20 lactic acid bacteria isolates from a traditional cheese was investigated. 6 isolates showed antibacterial effect against Gram positive bacteria.Streptococcus thermophilusT2 strain showed the wide inhibitory spectrum against the Gram positive bacteria. Growth and bacteriocin production profiles showed that the maximal bacteriocin production, byS. thermophilusT2 cells, was measured by the end of the late-log phase (90 AUml−1) with a bacteriocine production rate of 9.3 (AUml−1)h−1. In addition, our findings showed that the bacteriocin, produced byS. thermophilusT2, was stable over a wide pH range (4–8); this indicates that such bacteriocin may be useful in acidic as well as nonacidic food. This preliminarily work shows the potential application of autochthonous lactic acid bacteria to improve safety of traditional fermented food.

scholarly journals EFFECT OF EXOPOLISACCHARIDES OF LACTIC ACID BACTERIA ON THE SYNTHESIS OF PROINFLAMMATORY CYTOKINES BY MACROPHAGIC MICE IN PHAGOCYTOSIS OF STAPHYLOCOCCUS AUREUS

2018 ◽  
pp. 67-71
Author(s):  
G. T. Uryadova ◽  
E. A. Gorelnikova ◽  
N. A. Fokina ◽  
A. S. Dolmashkina ◽  
L. V. Karpunina
Keyword(s):  
Staphylococcus Aureus ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactococcus Lactis ◽  
Inflammatory Cytokines ◽  
Proinflammatory Cytokines ◽  
Streptococcus Thermophilus ◽  
Ambiguous Effect ◽  
Pro Inflammatory Cytokines

Aim. Study of the effect of exopolysaccharides (EPS) of lactic acid cocci on cytokine activity of macrophages of mice with phagocytosis in vitro Staphylococcus aureus 209-P. Materials and methods. The EPS of Streptococcus thermophilus and Lactococcus lactis B-1662 was used in the work. At 13, 5 and 7, AMP and PMP were isolated and the phagocytosis process was modeled in vitro. After 30 minutes, 1, 6 and 24 hours, the content of pro-inflammatory cytokines IL-1a and TNF-a was determined. Results. EPSs had an ambiguous effect on the production of cytokines. The greatest effect on the synthesis was provided by EPS of S. thermophilus. Conclusion. The results of the study allow us to talk about the possibility of using EPS of S. thermophilus as a preventive immunomodulator for correction of the cytokine status of animals.

scholarly journals Porphyra yezoensis Sauces Fermented With Lactic Acid Bacteria: Fermentation Properties, Flavor Profile, and Evaluation of Antioxidant Capacity in vitro

2022 ◽  
Vol 8 ◽  
Author(s):  
Jie Yang ◽  
Tengqi Gao ◽  
Feng Ge ◽  
Hao Sun ◽  
Zihang Cui ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antioxidant Capacity ◽  
Porphyra Yezoensis ◽  
Streptococcus Thermophilus ◽  
Gas Chromatography Mass Spectrometry ◽  
Reducing Ability ◽  
Volatile Flavor ◽  
Dpph Scavenging

The demand for roasted seaweed sandwich (Porphyra yezoensis) product has risen in recent years. The product slicing process has created a huge number of scraps that are not utilized effectively. Three lactic acid bacteria (LAB) strains were used to ferment P. yezoensis sauces in this study, including Lactobacillus fermentum, Lactobacillus casei, Streptococcus thermophilus, and the mixed strains (1:1:1, v/v). The fermentation characteristics, antioxidant capacity in vitro, sensory properties, and flavoring substances of fermented P. yezoensis sauces were analyzed. After 21 days of fermentation, all LAB strains grew well in the P. yezoensis sauces, with protease activity increased to 6.6, 9.24, 5.06, and 5.5 U/mL, respectively. Also, the flavors of P. yezoensis sauces fermented with L. casei and L. fermentum were satisfactory. On this premise, gas chromatography-mass spectrometry (GC-MS) was used to investigate the changes in gustatory compounds in P. yezoensis sauces fermented with L. casei and L. fermentum. In general, 42 and 41 volatile flavor chemicals were identified after the fermentation of L. casei and L. fermentum. Furthermore, the fermented P. yezoensis sauce possessed greater DPPH scavenging activity and ferric-reducing ability power than the unfermented P. yezoensis. Overall, the flavor and taste of P. yezoensis sauce fermented by L. casei was superior.

Influence of thermophilic lactic acid bacteria strains on propionibacteria growth and lactate consumption in an Emmental juice-like medium

1999 ◽  
Vol 66 (1) ◽  
pp. 105-113 ◽  
Author(s):  
ANNE THIERRY ◽  
DELPHINE SALVAT-BRUNAUD ◽  
JEAN-LOUIS MAUBOIS
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acids ◽  
Free Amino ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
The Media ◽  
Lactate Consumption ◽  
Thermophilic Lactic Acid Bacteria

Swiss-type cheeses such as Emmental are characterized by the successive development of thermophilic lactic acid bacteria (TLAB) and propionibacteria. The aim of this study was to determine whether the choice of TLAB strain influenced propionibacteria. TLAB and propionibacteria were cultured sequentially under the conditions prevailing in cheese. Firstly, 11 Emmental juice-like media were prepared by fermenting casein-enriched milk with pure or mixed cultures of TLAB (Lactobacillus helveticus, Lb. delbrueckii subsp. lactis and Streptococcus thermophilus), differing in their proteolytic activities. TLAB cells were then removed by microfiltration. Finally, five strains of Propionibacterium freudenreichii were grown on these media at 24°C under anaerobiosis and their growth characteristics and lactate consumption determined. The media mainly differed in their contents of peptides (1·9–5·3 g/kg) and free amino acids (1·0–5·6 g/kg) and the proportions of lactate isomers (42–92% of the L(+) isomer). Propionibacteria were significantly (P<0·05) influenced by TLAB strains (differences in doubling times of up to 20% and differences in lactate consumption after 600 h culture of up to 52%). The influence of TLAB was similar for all the propionibacteria tested, depended on the TLAB strains and could not be generalized to the TLAB species. Propionibacteria were stimulated by high peptide levels, low levels of free amino acids and NaCl, a low proportion of L(+)-lactate and other undetermined factors. However, variations due to TLAB were less than those between propionibacteria strains.

scholarly journals Large-scale genome-wide analysis links lactic acid bacteria from food with the gut microbiome

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Edoardo Pasolli ◽  
Francesca De Filippis ◽  
Italia E. Mauriello ◽  
Fabio Cumbo ◽  
Aaron M. Walsh ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gut Microbiome ◽  
Large Scale ◽  
Streptococcus Thermophilus ◽  
Fermented Food ◽  
Fermented Foods ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Stool Samples

Abstract Lactic acid bacteria (LAB) are fundamental in the production of fermented foods and several strains are regarded as probiotics. Large quantities of live LAB are consumed within fermented foods, but it is not yet known to what extent the LAB we ingest become members of the gut microbiome. By analysis of 9445 metagenomes from human samples, we demonstrate that the prevalence and abundance of LAB species in stool samples is generally low and linked to age, lifestyle, and geography, with Streptococcus thermophilus and Lactococcus lactis being most prevalent. Moreover, we identify genome-based differences between food and gut microbes by considering 666 metagenome-assembled genomes (MAGs) newly reconstructed from fermented food microbiomes along with 154,723 human MAGs and 193,078 reference genomes. Our large-scale genome-wide analysis demonstrates that closely related LAB strains occur in both food and gut environments and provides unprecedented evidence that fermented foods can be indeed regarded as a possible source of LAB for the gut microbiome.

Shelf-Life Studies of Vacuum-Packaged Bacon Treated with Nisin

1985 ◽  
Vol 48 (4) ◽  
pp. 330-333 ◽  
Author(s):  
C. CALDERON ◽  
D. L. COLLINS-THOMPSON ◽  
W. R. USBORNE
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Sodium Nitrite ◽  
Storage Life ◽  
Shelf Life Studies ◽  
Mrs Medium

The effect of various concentrations of nisin (250, 500 or 750 IU/g) combined with 50 ppm sodium nitrite on the shelf-life of vacuum-packaged bacon was evaluated. Control packages of bacon containing 50 and 150 ppm nitrite were included. Total numbers of lactic acid bacteria (LAB) (as measured on MRS medium) was used as a criterion for shelf-life. Treated bacon samples were stored at 30 and 5°C for 4 d or 6 wk, respectively. Bacon stored at 30°C showed a 1-d extension of shelf-life at nisin levels of 500 and 750 IU/g. Lowest counts at 6 wk were in bacon treated with 750 IU nisin and stored at 5°C. The LAB count was 1.5-log10 CFU/g lower than the controls. A 1-wk extension of storage life was predicted for nisin-treated (750 IU) bacon.

scholarly journals Biodiversity andγ-Aminobutyric Acid Production by Lactic Acid Bacteria Isolated from Traditional Alpine Raw Cow’s Milk Cheeses

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Elena Franciosi ◽  
Ilaria Carafa ◽  
Tiziana Nardin ◽  
Silvia Schiavon ◽  
Elisa Poznanski ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Random Amplified Polymorphic Dna ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Paracasei ◽  
Aminobutyric Acid ◽  
Cow’S Milk ◽  
Rrna Gene ◽  
Cow's Milk ◽  
Raw Cow’S Milk

“Nostrano-cheeses” are traditional alpine cheeses made from raw cow’s milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produceγ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n=97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated wereLactobacillus paracasei,Streptococcus thermophilus, andLeuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers wereLactobacillus paracaseibut other GABA producing species includedLactococcus lactis,Lactobacillus plantarum,Lactobacillus rhamnosus,Pediococcus pentosaceus, andStreptococcus thermophilus. NoEnterococcus faecalisorSc. macedonicusisolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was aSc. thermophilus.

Antibiotic susceptibility of different lactic acid bacteria strains

2011 ◽  
Vol 2 (4) ◽  
pp. 335-339 ◽  
Author(s):  
N. Karapetkov ◽  
R. Georgieva ◽  
N. Rumyan ◽  
E. Karaivanova
Keyword(s):  
Cell Wall ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Acidophilus ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Delbrueckii ◽  
Cell Wall Synthesis ◽  
High Susceptibility ◽  
Lactobacillus Delbrueckii Subsp

Five lactic acid bacteria (LAB) strains belonging to species Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis and Streptococcus thermophilus were tested for their susceptibility to 27 antibiotics. The minimum inhibitory concentrations of each antimicrobial were determined using a microdilution test. Among the strains a high susceptibility was detected for most of the cell-wall synthesis inhibitors (penicillins, cefoxitin and vancomycin) and resistance toward inhibitors of DNA synthesis (trimethoprim/sulfonamides and fluoroquinolones). Generally, the Lactobacillus strains were inhibited by antibiotics such as chloramphenicol, erythromycin and tetracycline at breakpoint levels lower or equal to the levels defined by the European Food Safety Authority. Despite the very similar profile of S. thermophilus LC201 to lactobacilli, the detection of resistance toward erythromycin necessitates the performance of additional tests in order to prove the absence of transferable resistance genes.

Microstructure and rheology of an acid-coagulated cheese (Karish) made with an exopolysaccharide-producing Streptococcus thermophilus strain and its exopolysaccharide non-producing genetic variant

2004 ◽  
Vol 71 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Ashraf N Hassan ◽  
Milena Corredig ◽  
Joseph F Frank ◽  
Morsi Elsoda
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Physical Properties ◽  
Creep Test ◽  
Genetic Variant ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Protein Network ◽  
Dynamic Rheology ◽  
Soft Acid

The objective of this research was to determine the effect of exopolysaccharide (EPS) production by lactic acid bacteria on the microstructure and rheology of Karish cheese, a soft acid coagulated cheese made using skim milk. An EPS-producing strain of Streptococcus thermophilus, and its EPS non-producing genetic variant were used to make comparable batches of the cheese. EPS in cheese was visualized by cryo-SEM as a large, dense, filamentous mass. Cheese made with the EPS non-producing culture was characterized by a dense protein network with smaller pores compared to that prepared with the EPS-producing culture. High elastic and viscous moduli measured by dynamic rheology were observed for EPS negative cheese and was attributed to its dense protein network. Creep test experiments demonstrated that cheese prepared with the EPS non-producing strain was more rigid and recovered its deformation, while cheese made using the EPS producing culture was more deformable. These results indicate that EPS-producing cultures can improve the physical properties of Karish cheese by reducing undesirable rigidity.

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