Taxonomic group: bacteria / Firmicutes
(Phylum: Firmicutes)
The structure was elucidated in this paperNCBI PubMed ID: 31846658Publication DOI: 10.1016/j.ijbiomac.2019.12.108Journal NLM ID: 7909578Publisher: Butterworth-Heinemann
Correspondence: A. Bouallegue <amir.bouallegue
enis.tn>; F. Chaari <c.fatma
yahoo.fr>
Institutions: Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126 Napoli, Italy, Laboratory for the Improvement of Plants and Valorization of Agroressources, National School of Engineering of Sfax (ENIS), Soukra Road, km 3.5, B.P. 1173, 3038 Sfax, Tunisia, Faculty of Sciences of Gabès, University of Gabès, Gabès, Tunisia, Department of Experimental Medicine, Section of Biotechnology, University of Campania 'Luigi Vanvitelli', via de Crecchio 7, I-80138 Napoli, Italy, Common Service Unit of Bioreactor Coupled with an Ultrafilter, National School of Engineering, Sfax University, P.O. Box 1173, 3038 Sfax, Tunisia
A strain of Bacillus subtilis AF 17 with high exopolysaccharide (EPS) production ability was isolated and identified based on morphological and physiological characteristics and phylogenetic analysis of 16S rDNA sequences. EPS was isolated from the strain fermentation broth by alcohol precipitation and gel-filtration chromatography. Its structural characteristics were investigated and elucidated by methylation analysis, gas chromatography mass spectrometry and nuclear magnetic resonance spectroscopy. Based on the obtained data, the EPS was found to be a levan containing a backbone of 6-substituted beta-fructoses, with a low grade of branching at position 1 (linear/branched ratio 20:1). Levan showed a molecular weight of about 20 MDa. The antioxidant activity of this biopolymer was studied and revealed that levan showed an interesting 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity (IC50 levan = 1.42 mg/mL), reducing power, and also a strong total antioxidant activity. Overall, the results suggest that levan is a promising source of natural antioxidants and can be used as additive in food and pharmaceutical preparations.
exopolysaccharides, purification, Structural characterization, Antioxidant activity, Bacillus subtilis AF17
Structure type: polymer chemical repeating unit ; 20000000
Location inside paper: p.321, Fig.7
Trivial name: levan
Compound class: EPS, polyfructan
Contained glycoepitopes: IEDB_923066
Methods: 13C NMR, 1H NMR, NMR-2D, methylation, GC-MS, sugar analysis, GPC, phylogenetic analysis, morphological analysis, antioxidant activity assay
NCBI Taxonomy refs (TaxIDs): 1423Reference(s) to other database(s): GTC:G94003ED
Show glycosyltransferases
NMR conditions: in D2O at 298 K
[as TSV]
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
6 bDFruf 61.2 105.4 77.5 76.3 81.5 64.7
6,6,1 bDFruf 61.2 104.8 77.5 76.3 82.2 63.4
6,6 bDFruf 61.2 105.4 77.5 76.3 81.5 64.7
bDFruf
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
6 bDFruf 3.67-3.77 - 4.19 4.10 3.95 3.35-3.90
6,6,1 bDFruf 3.67-3.75 - 4.19 4.11 3.88 3.73-3.85
6,6 bDFruf 3.67-3.77 - 4.19 4.10 3.95 3.35-3.90
bDFruf
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
6 bDFruf 61.2/3.67-3.77 77.5/4.19 76.3/4.10 81.5/3.95 64.7/3.35-3.90
6,6,1 bDFruf 61.2/3.67-3.75 77.5/4.19 76.3/4.11 82.2/3.88 63.4/3.73-3.85
6,6 bDFruf 61.2/3.67-3.77 77.5/4.19 76.3/4.10 81.5/3.95 64.7/3.35-3.90
bDFruf
1H NMR data:
| Linkage | Residue | H1 | H2 | H3 | H4 | H5 | H6 |
|---|
| 6 | bDFruf | 3.67
3.77 |
| 4.19 | 4.10 | 3.95 | 3.35
3.90 |
| 6,6,1 | bDFruf | 3.67
3.75 |
| 4.19 | 4.11 | 3.88 | 3.73
3.85 |
| 6,6 | bDFruf | 3.67
3.77 |
| 4.19 | 4.10 | 3.95 | 3.35
3.90 |
| | bDFruf | |
|
13C NMR data:
| Linkage | Residue | C1 | C2 | C3 | C4 | C5 | C6 |
|---|
| 6 | bDFruf | 61.2 | 105.4 | 77.5 | 76.3 | 81.5 | 64.7 |
| 6,6,1 | bDFruf | 61.2 | 104.8 | 77.5 | 76.3 | 82.2 | 63.4 |
| 6,6 | bDFruf | 61.2 | 105.4 | 77.5 | 76.3 | 81.5 | 64.7 |
| | bDFruf | |
|
There is only one chemically distinct structure:
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