Lund University Publications

@article{4f651392-d5af-4d11-9c0d-e4459468b35c,
  abstract     = {{Bacterial exopolysaccharides (EPS) have emerged as one of the key <br>
players in the field of heavy metal-contaminated environmental <br>
bioremediation. This study aimed to characterize and evaluate the metal <br>
biosorption potential of EPS produced by a novel <i>Psychrobacillus</i> <br>
strain, NEAU-3TGS, isolated from an iron ore deposit at Tamra iron mine,<br>
 northern Tunisia. Genomic and pan-genomic analysis of NEAU-3TGS <br>
bacterium with nine validated published <i>Psychrobacillus</i> species <br>
was also performed. The results showed that the NEAU-3TGS genome (4.48 <br>
Mb) had a mean GC content of 36%, 4,243 coding sequences and 14 RNA <br>
genes. Phylogenomic analysis and calculation of nucleotide identity <br>
(ANI) values (less than 95% for new species with all strains) confirmed <br>
that NEAU-3TGS represents a potential new species. Pangenomic analysis <br>
revealed that <i>Psychrobacillus</i> genomic diversity represents an <br>
“open” pangenome model with 33,091 homologous genes, including 65 core, <br>
3,738 shell, and 29,288 cloud genes. Structural EPS characterization by <br>
attenuated total reflectance-Fourier transform infrared (ATR-FTIR) <br>
spectroscopy showed uronic acid and α-1,4-glycosidic bonds as dominant <br>
components of the EPS. X-ray diffraction (XRD) analysis revealed the <br>
presence of chitin, chitosan, and calcite CaCO<sub>3</sub> and confirmed<br>
 the amorphous nature of the EPS. Heavy metal bioabsorption assessment <br>
showed that iron and lead were more adsorbed than copper and cadmium. <br>
Notably, the optimum activity was observed at 37°C, pH=7 and after 3 h <br>
contact of EPS with each metal. Genomic insights on iron acquisition and<br>
 metabolism in <i>Psychrobacillus</i> sp. NEAU-3TGS suggested that no genes involved in siderophore biosynthesis were found, and only the gene cluster <i>Feu</i>ABCD<br>
 and trilactone hydrolase genes involved in the uptake of siderophores, <br>
iron transporter and exporter are present. Molecular modelling and <br>
docking of <i>Feu</i>A (protein peptidoglycan siderophore-binding protein) and siderophores ferrienterobactine [Fe<sup>+3</sup> (ENT)]<sup>-3</sup> and ferribacillibactine [Fe<sup>+3</sup> (BB)]<sup>-3</sup> ligand revealed that [Fe<sup>+3</sup> (ENT)]<sup>-3</sup> binds to Phe122, Lys127, Ile100, Gln314, Arg215, Arg217, and Gln252. Almost the same for [Fe<sup>+3</sup> (ENT)]<sup>-3</sup><br>
 in addition to Cys222 and Tyr229, but not Ile100.To the best of our <br>
knowledge, this is the first report on the characterization of EPS and <br>
the adsorption of heavy metals by <i>Psychrobacillus</i> species. The heavy metal removal capabilities may be advantageous for using these organisms in metal remediation.}},
  author       = {{Najjari, Afef and Jabberi, Marwa and Chérif, Saïda Fatma and Cherif, Ameur and Ouzari, Hadda Imene and Linares-Pastén, Javier A. and Sghaier, Haitham}},
  issn         = {{1664-302X}},
  language     = {{eng}},
  month        = {{08}},
  publisher    = {{Frontiers Media S. A.}},
  series       = {{Frontiers in Microbiology}},
  title        = {{Genome and pan-genome analysis of a new exopolysaccharide-producing bacterium <i>Pyschrobacillus sp.</i> isolated from iron ores deposit and insights into iron uptake}},
  url          = {{http://dx.doi.org/10.3389/fmicb.2024.1440081}},
  doi          = {{10.3389/fmicb.2024.1440081}},
  volume       = {{15}},
  year         = {{2024}},
}