Microbial Enzymes from Nigerian Dumpsites as Natural Biocatalysts: A Critical Review of LDPE Degradation Mechanisms and Biotechnological Potential

Microbial communities thriving in Nigerian dumpsites represent an underexplored ecological reservoir of potent oxidative and hydrolytic enzymes with remarkable biocatalytic capabilities. These organisms inhabit chemically complex, stress-laden environments that select for metabolic versatility, enabling certain taxa to initiate and sustain the biodegradation of low-density polyethylene (LDPE), one of the most recalcitrant synthetic polymers. This critical review interrogates the strength of current evidence supporting LDPE biodegradation by indigenous bacteria, highlighting both the promise and the limitations of existing studies. Whilst numerous reports attribute polymer breakdown to enzymes such as oxygenases, peroxidases, esterases, and oxidoreductases, most findings rely on indirect assays, lack mechanistic validation, and are constrained by methodological inconsistencies. By reframing these microbial enzymes as natural biocatalysts, the review underscores their broader biotechnological and pharmacognostic potential, including applications in green chemistry, biotransformation, and environmental detoxification. Significant knowledge gaps persist, particularly in enzyme purification, kinetic characterization, structural elucidation, and omics-driven discovery. Addressing these gaps will be essential for advancing both the scientific understanding of LDPE biodegradation and the translational potential of dumpsite-derived microbial enzymes as valuable natural resources.