Pseudomonas fluorescens mediated plastic degradation and influence of UV pretreatment

Abstract The escalating environmental threat caused by the accumulation of recalcitrant synthetic plastics necessitates the development of effective bioremediation strategies. This study investigates the biodegradation potential of Pseudomonas fluorescens on two distinct substrates: two-dimensional PET (Polyethene Terephthalate) sheets and three-dimensional PS (Polystyrene) blocks. The influence of UV-pretreatment on microbial degradation efficiency was also evaluated. A sequential batch culture method was employed for four weeks at 30 °C. Degradation was monitored via gravimetric analysis, Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR). UV-pretreatment significantly enhanced biodegradation efficiencies, resulting in higher percentage weight losses by the fourth week, for both PET (7.11% for UV-pretreated vs. 5.33% for untreated samples) and PS (41.42% for UV-pretreated vs. 32.5% for untreated samples). SEM analysis revealed progressive structural deterioration; PET samples displayed severe fracturing and flaking, while PS blocks exhibited major hollow cavity formations in the structure causing the loss of structural integrity. The PET samples also showed significant changes in the FTIR peaks in the third and fourth weeks in the wave number regions 1000 cm −1 to 1700 cm −1 , indicating the loss of integrity in the polymer structure, leading to significant fragmentation. FTIR of PS suggested that the accelerated onset of biodegradation was driven by early and prominent formation of hydroxy/hydroperoxide groups evident from the broadening of the peak at 3400 cm −1 . This study suggests that P. fluorescens effectively destabilizes polymer integrity by inducing both surface erosion and molecular cleavage, highlighting its promise for sustainable plastic waste mitigation.