The probiotic features of strain GM newly isolated from Tunisian spontaneously fermented goat milk and identified as Bacillus tequilensis-GM were assessed. Strain GM showed high resistance to saliva (90.64%), gastric juice (88.55%), intestinal juice (72.83%) and resistance to bile salts (65.22%), was able to act against Listeria monocytogenes ATCC 15313, Escherichia coli ATCC 25922 and Enterococcus feacalis ATCC 25912, showed high surface hydrophobicity (77.3%) and was sensitive to most of the studied antibiotics. Strain GM did not exhibit any hemolytic activity whereas it was able to produce protease, amylase and β-galactosidase. Moreover, results showed that strain GM produced high molecular weight β-(2→6)-levan with high ability to inhibit and to disrupt pathogenic biofilms and with high ability to reduce syneresis of sucrose-supplemented skimmed milk. B. tequilensis-GM can therefore be suitable to be used as starter culture in fermented dairy products, since it possesses desirable probiotic properties in addition to its ability to produce levan.

Structural characterization, levan, antibiofilm activity, Bacillus tequilensis-GM, food application, probiotic potential

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
6,1	bDFruf	62.2	105.3	78.8	76.0	82.8	63.9
6	bDFruf	61.6	106.0	78.0	76.9	82.0	65.1
	bDFruf	61.6	106.0	78.0	76.9	82.0	65.1


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
6,1	bDFruf	3.67-3.75	-	4.19	4.11	3.87	3.73-3.85
6	bDFruf	3.67-3.77	-	4.19	4.10	3.95	3.55-3.90
	bDFruf	3.67-3.77	-	4.19	4.10	3.95	3.55-3.90


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
6,1	bDFruf	62.2/3.67-3.75		78.8/4.19	76.0/4.11	82.8/3.87	63.9/3.73-3.85
6	bDFruf	61.6/3.67-3.77		78.0/4.19	76.9/4.10	82.0/3.95	65.1/3.55-3.90
	bDFruf	61.6/3.67-3.77		78.0/4.19	76.9/4.10	82.0/3.95	65.1/3.55-3.90

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]OC[C@H]1O[C@@](CO[C@]2(CO)O[C@H](CO)[C@@H](O)[C@@H]2O)(OC[C@H]2O[C@]([*])(CO)[C@@H](O)[C@@H]2O)[C@@H](O)[C@@H]1O

486.423 g/mol (C₁₈H₃₀R₂O₁₅, R = next and previous repeats, not counted in mol weight)

An exopolysaccharide (EPS_B3) produced by a Leuconostoc mesenteroides strain isolated from a semi-hard Italian cheese was chemically and biologically characterized. HPLC-SEC, NMR, FT-IR and monosaccharide composition experiments were performed. Antimicrobial, antibiofilm, bifidogenic, antioxidant, and DNA-protective activity of EPS_B3 were also studied. Results revealed that EPS_B3 was a mixture of two high-molecular-weight dextran with low branching degree. Moreover, EPS_B3 displayed significant antibacterial activity against eight foodborne pathogens and inhibited biofilm formation by Listeria monocytogenes. EPS_B3 also evidenced bifidogenic activity, stimulating the growth of three probiotic bifidobacteria, and improving the tolerance of Bifidobacterium animalis subsp. lactis to oxygen stress. It also protected plasmid DNA from hydrogen peroxide damage. Only limited antioxidant capacity was observed. In conclusion, data suggest that EPS_B3 might be exploited in the context of functional foods especially for its marked antimicrobial activity as well as for the ability to improve the viability of bifidobacteria in probiotic foods. However, further studies should be carried out to assess the ability of EPS_B3 to reach intact the target site (i.e., gastrointestinal tract) to consider the possibility of use it as a new functional ingredient in foods.

exopolysaccharide, Leuconostoc, Dextran, antimicrobial activity, bifidogenic activity

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]OC[C@H]1O[C@H]([*])[C@H](O)[C@@H](O[C@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)[C@@H]1O

324.282 g/mol (C₁₂H₂₀R₂O₁₀, R = next and previous repeats, not counted in mol weight)

The production of rhamnolipid (glycolipid) biosurfactant was achieved under optimized conditions from newly isolated bacteria (Pseudomonas plecoglossicida BP03) from rice mill effluent. The isolated biosurfactant was structurally characterized using FTIR and NMR spectroscopic studies. The obtained biosurfactant (1·39 g l-1 ) showed a variety of applications including larvicidal and pupicidal activity against malarial vector (Anopheles sunadicus). It also exhibited antimicrobial activity against human pathogens, and possessed potent anti-biofilm activity against Staphylococcus aureus, Bacillus subtilis and Aeromonas hydrophila. The obtained biosurfactant showed a dose-dependent inhibition of exopolymeric substance (EPS) and growth curve in S. aureus. Furthermore, the cytotoxicity assays revealed that the biosurfactant exhibit a cytotoxic potency against the human fibroblastic sarcoma cells Ht-1080. An in silco analysis was also performed using Schrodinger maestro 9.3 against surface protein (SasG) of S. aureus, and the resultant analysis revealed an interactive docking score of -3·4 kcal mol-1. The obtained result indicates that the synthesized economically viable biosurfactant ensures excellent applications towards various fields.

cytotoxicity, Biofilm, rhamnolipid, antimicrobial activity, larvicidal activity, schrodinger maestro 9.3

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCCCC(CC(=O)O)OC(=O)CC(CCCCCCC)O[C@@H]1O[C@@H](C)[C@H](O)[C@@H](O)[C@H]1O

504.661 g/mol (C₂₆H₄₈O₉)