Biofilm-mediated surface depolymerization of multiple synthetic polymers by mangrove-derived bacterial consortia

Area of Science:

• Environmental Microbiology
• Polymer Science
• Biotechnology

Background:

• Plastic pollution is a global environmental crisis due to synthetic polymers' resistance to degradation.
• Microbial degradation of plastics is known, but the mechanisms and extent of biofilm involvement are not fully understood.

Purpose of the Study:

• To investigate the potential of mangrove-derived bacterial consortia in initiating the early-stage degradation of common synthetic polymers.
• To elucidate the mechanistic basis of biofilm-mediated plastic deterioration.

Main Methods:

• Incubation of polyethylene terephthalate (PET), polystyrene (PS), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) with mangrove bacterial consortia for 120 days.
• Analysis of polymer mass loss, surface morphology (SEM, AFM, CLSM), chemical structure (FTIR, EDX), and mechanical properties (tensile testing).
• Application of first-order kinetic models to gravimetric data for degradation dynamics estimation.

Main Results:

• Significant mass loss and surface erosion observed, with PS (20.14%) and PET (8.33%) showing highest susceptibility.
• Evidence of extensive biofilm formation, nanoscale pitting, and oxidative functional group incorporation on polymer surfaces.
• Reduced mechanical integrity confirmed by tensile testing, indicating surface-driven structural weakening.

Conclusions:

• Environmentally adapted microbial consortia from mangrove sediments can initiate biofilm-driven surface depolymerization of plastics.
• Mangrove ecosystems harbor plastic-degrading microbes, representing an underexplored resource for biotechnological applications.
• Findings advance the understanding of early-stage plastic biodegradation and inform strategies for microplastic remediation.