Abstract Description

Sustainable bioremediation strategies are urgently needed to address the limited availability of arable land and restore land that has been degraded through excessive and sometimes improper use. This study aims to harness the metabolic potential of native bacteria strains develop a microbial-based bioremediation approach that could provide an environmentally friendly solution. Native bacterial strains were isolated low-rank coal (LRC), motor oil-contaminated soils, and dam sediments. These isolated bacteria were purified and characterized morphologically. Physicochemical properties of the three samples was performed to understand microbial activity under polluted conditions. However, the LRC substrate revealed a pH of 3.60, with a background S content equivalent to 7.13 g L-1, N at 20 mg L-1, P at 7.8 mg L-1, and K at 3.3 mg L-1. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed a carbon (C) and oxygen (O) content of 23.09% and 69.03%, respectively. Biochemical assays demonstrated that 44% of the isolates exhibited phosphate solubilisation with indices between 16 and 22mm. Indole-3-acetic acid (IAA) production ranged from 3.6 to 27.7 mg/L, and 88% produced ammonia. Strains that exhibited plant growth-promoting (PGP) traits (IAA, GA3, and NPK) were selected and assessed for their responses to abiotic stress tolerance (pH, temperature, and salinity) and biotic interactions, including synergistic, antagonistic, and additive effects. Stress tolerance screening showed that 13 isolates grew in salinity up to 32g NaCl, 1 tolerated acidic conditions down to pH 4, and 15 maintained growth in the presence of low temperature of 40C. These findings indicate that a subset of the isolates are not only metabolically versatile but also resilient to the abiotic stresses characteristic of polluted soils. However, this evaluation was conducted before investigating their potential to degrade petroleum hydrocarbon pollutants. Sample metagenomic profiling will be used to understand microbial community dynamics, while interactions such as synergistic, antagonistic, and additive effects will be evaluated and quantified. Following the optimization of bioremediation efficiency through enrichment cultures, bacterial consortia will be employed to verify the effectiveness of biodegradation. The results of this study further demonstrate the potential of custom-tailored microbial communities from local environments for practical bioremediation. These findings will lay the groundwork for developing sustainable, site-specific bioremediation strategies to mitigate hydrocarbon pollution, supporting global environmental and agricultural sustainability objectives.