Biomass Assessment and Optimization of Alcaligenes faecalis Isolated from some Nigerian Mining Sites for Heavy Metal Uptake Using Response Surface Methodology Model

Abstract

In this study, we investigated the heavy metal absorption of Alcaligenes faecalis strain U.B.I., a bacteria isolated from a mining site, under different environmental conditions. We utilized both conventional and molecular techniques to identify the bacteria and employed response surface methodology (R.S.M.) to determine optimal environmental conditions for heavy metal absorption. Our analysis revealed that the heavy metal-tolerant bacteria belong to the Proteobacteria, specifically the Betaproteobacteria order in the Burkholderiales family. Additionally, the bacteria’s phylogenetic characteristics indicated a close relationship between the Aeromonas sp. cluster and members of the Aeromonadaceae family. Our results showed that the biomass A. faecalis strain U.B.I. had an optimal potential for chromium (Cr+) absorption at 93.0%. We also conducted tests on the biomass under optimized conditions for lead (Pb2+) absorption using R.S.M., resulting in a mean heavy metal uptake of 89.99%. Furthermore, we analyzed the surface functional groups after interaction with heavy metals and observed a significant shift in position of the functional groups. The O-H stretch and H-bonded at the 3268 cm1 position, while C=C stretch and N-O asymmetrical stretch/C-O stretch occurred at positions 2195 cm-1 and 1629 cm-1 of the spectra, respectively. Our findings suggest that the biomass of A. faecalis strain U.B.I. has potential for heavy metal bioremediation and can be used for heavy metal biosorption under various environmental conditions.