Degradation of Glycerol and Diesel by Klebsiella Pneumoniae Isolated from Domestic Liquid Waste Polluted Soil in University of Ilorin, Kwara State

Pollution from petroleum products and industrial byproducts poses a significant environmental challenge, especially in developing countries with poor waste management systems. This study investigates the biodegradation potential of Klebsiella pneumoniae isolated from domestic liquid waste polluted soil in the University of Ilorin, Nigeria. The objective is to evaluate the organism’s ability to degrade glycerol and diesel, two common organic pollutants in kitchen and drainage effluents. A laboratory-based experimental design was used. Soil samples were collected from two domestic liquid waste polluted sites and screened for hydrocarbon degrading bacteria. The isolate with the highest biosurfactant activity, identified as Klebsiella pneumoniae, was selected. The bacterium was cultured in mineral salt medium separately enriched with 2% glycerol and 2% diesel. Microbial growth was monitored over 21 days using optical density (OD₆₀₀), emulsification index (E24%), and Gas Chromatography-Mass Spectrometry (GC-MS) analysis to assess degradation. Klebsiella pneumoniae showed consistent growth and emulsification in both media. In glycerol medium, steady growth and moderate E24% (33.3%–46.2%) were observed. Diesel medium showed slower initial growth but higher emulsification (up to 66.6%). GC-MS analysis revealed a reduction in hydrocarbon peaks and the appearance of degradation metabolites such as alcohols, esters, and amides in treated samples, confirming biodegradation. These findings demonstrated that Klebsiella pneumoniae can effectively degrade both hydrophilic and hydrophobic pollutants. Its biosurfactant production enhances diesel degradation, while its metabolic versatility supports glycerol assimilation. This suggests its potential as a native bioremediation agent for managing mixed organic pollutants in domestic wastewater and supports ecofriendly remediation strategies aligned with sustainable development goals.