Polystyrene and low-density polyethylene degradation by Bacillus cereus L1 isolated from plastic contaminated wastewater

The environmental disruption caused by enduring pollution has been aggravated by the excessive use of low-density polyethylene (LDPE) and polystyrene (PS) plastics due to their non-biodegradable composition. Microbial bioremediation could be an environmentally friendly approach to degrade these pollutants. In this research, plastic-degrading bacteria were isolated from plastic-polluted wastewater collected from a wastewater drain. For this study, enrichment culture techniques were employed to isolate plastic-degrading bacteria from wastewater contaminated with plastic. Characterization was performed on the purified isolate with the highest efficiency. The bacteria utilizing PS and LDPE as the sole carbon sources were purified and characterized (FTIR, SEM) based on morphology, antibiotic resistance profile, and phylogenetic analysis through 16 S rRNA gene sequencing. The bacteria showing the most significant PS and LDPE degradation were identified as B. cereus L1. The strain also exhibited biofilm-forming ability, confirmed by a qualitative crystal violet ring test, a pivotal factor in plastic breakdown. B. cereus L1 reduced the weight of LDPE beads from 1.08 g to 0.87 g and from 1.15 g to 0.92 g in four weeks. Fourier Transform Infrared Radiation (FTIR) spectroscopy revealed changes in the structural configuration of PS and LDPE after incubation with B. cereus L1, as distinct peaks at 2196 cm⁻¹ for alkynes, nitriles, and 1715 cm⁻¹ for carbonyl groups were observed, indicating the degradation of the polymers. This work highlights the potential of B. cereus L1 in bioremediation strategies for managing plastic waste, offering a sustainable and eco-friendly alternative for combating plastic pollution in both terrestrial and aquatic ecosystems.