Plastic-contaminated soil inherent novel strain Microbacterium hydrocarbonoxydans KRS13 demonstrates significant applicability toward biofilms formation and degradation of polypropylene

A polypropylene (PP) degrading bacterium derived from plastic waste site was identified as Microbacterium hydrocarbonoxydans KRS13 following 16S rDNA sequence analysis. Biodegradation assay for 90 days based on gravimetric method demonstrated a measurable weight reduction of 2.1 ± 0.10% in un-pretreated polypropylene films. The protein content and viability of KRS13 in terms of CFU/cm² was examined along with hydrophobicity and biosurfactant characterization. The polypropylene degradation was assessed through analytical techniques such as FTIR, EDX, FE-SEM and GC-MS. Robust growth of KRS13 as indicated by CFU (10⁸ CFU mL^-1) and protein content (4.71 µg mL^-1) demonstrated efficient biofilm formation and polypropylene degradation along with a removal rate of 0.00024 day^-1 (t₁/₂ = 2887.5 days). FE-SEM analysis revealed holes, cracks, and roughening on plastic surface, whereas increased oxygen (13.9%) and decreased carbon (86.1%) content noticed in EDX analysis. FTIR detected carbonyl and oxygenated groups, supported by increased keto, ester carbonyl and vinyl bond indices. Pretreatment of PP films on biodegradation also assessed by gravimetric method that displayed highest degradation (3.2 ± 0.4%) among UV treated films. Collectively, these findings highlight the significant potential of our strain M. hydrocarbonoxydans strain KRS13 as an effective PP degrader, supporting sustainable microbial-mediated biodegradation of plastic waste for PP waste management.