Isolation, Molecular Characterization and Antimicrobial Potential of Bacteria Associated with Banana (Musa spp.) Pseudostem Water

Abstract

Banana pseudostem is an underutilized agricultural by-product that contains
nutrients and bioactive compounds and may serve as a potential source of
microorganisms with biotechnological importance. The present study was undertaken
to isolate and characterize bacteria associated with banana pseudostem water and to
evaluate their antimicrobial potential. Banana pseudostem water was serially diluted
and cultured on de Man–Rogosa–Sharpe (MRS) agar for bacterial isolation. The
isolates were characterized based on colony morphology, Gram staining, biochemical
tests, and molecular identification using 16S rRNA gene sequencing. Antibacterial,
antifungal, and haemolytic activities were also evaluated. At a dilution of 10⁻³, an
average viable bacterial count of 3.2 × 10⁵ CFU/mL was recorded, and two
morphologically distinct isolates, designated Y1 and W1, were obtained. Both isolates
were Gram-positive rods and exhibited distinct biochemical profiles. Molecular
analysis identified Y1 as Klebsiella pneumoniae, while W1 was assigned to a Bacillus-
related taxon based on 16S rRNA sequence analysis. The isolates showed variable
antagonistic activity against the tested bacterial and fungal pathogens. No significant
antibacterial inhibition was observed against Staphylococcus aureus and Vibrio
cholerae, whereas slight inhibition was observed against Salmonella spp. Both isolates
demonstrated antifungal activity against the tested fungal isolates. Haemolytic activity
was also observed on blood agar, indicating the need for further safety assessment
before potential food, probiotic, or therapeutic applications. Overall, the study
demonstrates that banana pseudostem water represents a potential source of cultivable
bacteria with antimicrobial properties and highlights the value of banana agricultural
waste as a resource for microbial and biotechnological applications. Further studies
involving comprehensive molecular characterization, metabolite profiling,
mechanism-of-action studies, and biosafety evaluation are required to establish their
practical applications.