Investigation of the Solid Waste Degradation Potential and Molecular Identification of Bacteria Isolated from Municipal Solid Waste-Contaminated Soils in Uyo Metropolis, Akwa Ibom State, Nigeria

The soil is an important sink for waste disposal which has become a serious environmental challenge due to the associated impacts. This study was a comparative study of the bacterial communities across three municipal solid wastes (MSW)-contamianted soils with a pristine soil in Uyo, Akwa Ibom State, Nigeria; it further screened and molecularly identified the best MSW utilizers among the bacterial isolates obtained from culture-dependent analysis using an enrichment-based assay and Sanger sequencing, respectively. The viable counts from the Oron road site were significantly (P < 0.05) higher with 1.47 × 108 ± 1.3 CFU g⁻¹ at the 0-15cm depth and 1.21 × 108 ± 2.1 CFU g⁻¹ at the 15- 30 cm depth. The lowest counts were observed from Ikot Ekpene road site with 9.9 × 107 ± 0.8 CFU g⁻¹ at the 0-15 cm depth and 3.8 × 107 ± 2.0 CFU g⁻¹ at the 15-30 cm depth. In all, the pristine soil location had the lowest counts of 4.5 x 104 ± 0.3 CFU g⁻¹ at the 0-15 cm depth and 2.1 × 104 ± 0.3 CFU g⁻¹ at the 15-30 cm depth. The culture-based characterization identified the isolates as species from the genera Staphylococcus, Enterobacter, Pseudomonas, Escherichia, etc. with those of Bacillus having the highest occurrence. Bacillus sp., Enterococcus sp. and Pseudomonas aeruginosa were found across the dumpsites (100%). Bacillus sp. and Pseudomonas aeruginosa showed the strongest growth under the degradation-screening conditions and were identified as Bacillus sp. (PV810158.1) and Pseudomonas aeruginosa (PV810157.1), respectively by the 16S rRNA gene analysis. As indicated, these waste-contaminated soils harbor high bacterial population than the selected pristine soil and different species that are actively using the waste materials as energy and carbon sources for their growth and development. The municipal solid waste-utilization ability of the isolates makes them promising candidates for application in bioeconomy where they can be used for biological MSW treatment and bioremediation of MSW-contaminated soils.