Phenotypic and genotypic insights into a halotolerant bacterium with antimicrobial potential from El Golea Lake
Abstract
Introduction: The antimicrobial potential of a halotolerant bacterial strain, LMB3982, isolated from the
hypersaline Lake El Golea in Algeria at 25% NaCl (w/v), was investigated. The study aimed to evaluate the
antimicrobial activity of this strain and to characterize its phenotypic and genotypic properties, with a focus on
its bioactive compounds and environmental adaptability.
Methods: The strain was subjected to primary and secondary screenings for antimicrobial activity against a
panel of test microorganisms. The influence of growth medium and incubation time on the production of
antimicrobial metabolites was assessed. Various organic solvents were used to extract antimicrobial compounds,
which were then evaluated for their efficacy. Thin-layer chromatography (TLC) was performed on chloroformic
extracts using three solvent systems, and chemical properties were analyzed using infrared (IR) s pectroscopy.
Additionally, a taxonomic study based on phenotypic and genotypic identification, including 16S rRNA gene
sequencing, was conducted.
Results: Strain LMB3982 demonstrated significant antimicrobial activity against most test microorganisms, with
maximum activity observed after 72 hours of culture on nutrient agar. Chloroform was identified as the most
effective solvent for extracting bioactive compounds. TLC analysis revealed the presence of two types of
molecules: amines and phenols. IR spectros copy confirmed these findings, showing characteristic peaks
corresponding to these compounds. Biochemical tests indicated that the strain could produce various enzymes,
utilize multiple sugars, and grow under a wide range of conditions: NaCl concentrations of 0–25%, pH levels of
5–11, and temperatures of 15–37°C. Phylogenetic analysis of the 16S rRNA gene sequence positioned strain
LMB3982 as a novel taxon within the Bacillales order, showing 96% similarity to Bacillus pseudofirmus and
93.3% to Bacillus halodurans
Conclusion:. These findings highlight the potential of strain LMB3982 for biotechnological applications,
particularly in the production of novel antimicrobial compounds and enzymes adapted to extreme conditions.
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