Evaluation of the characterization and heavy metals remediation potential of biosurfactant produced by Aeromonas hydrophila S62A

Abstract

The evaluation of the heavy metals remediation potential and characterization of biosurfactant produced by Aeromonas hydrophilia strain S62A isolated from water and sediment samples of Imo River, Nigeria was studied. In this study, 12 bacterial isolates were isolated from contaminated water and sediment samples using spread plate technique and primarily screened for biosurfactant production using emulsification index, oil displacement and surface tension tests. Secondary biosurfactant production was carried out in a modified mineral salt medium under optimized conditions for 5 days and the produced biosurfactant was characterized and evaluated for its heavy metals removal efficiencies using standard analytical procedures. The result showed that the bacterial strain identified as Aeromonas hydrophilia S62A out of the 12 isolate strains had the highest and lowest values of 66.66 %, 23.76 cm and 90 mN/m for emulsification index, oil displacement and surface tension tests, respectively. The purified biosurfactant was found to be glycophospholipid as confirmed by the gas chromatographic (GC) and Fourier Transformed Infra-Red Spectroscopic (FTIR) profiles with 5 mg/mL critical micelles concentration (CMC). Statistically, significant differences (P < 0.05) were detected among the means of all surfactant CMC treatment in comparison to their untreated controls with 2 × CMC lead having the highest (98.92 %) and control (water) having the lowest (2.09 %) heavy metals removal efficiencies. Therefore, the present study has produced glycophospholipid biosurfactant with unique structural and chemical features and composition and could be exploited in environmental remediation of heavy metals contaminated ecosystems.