Biodegradation Behavior and Microbial Interactions of Biomass-Derived Polyester Blends in Marine Environments

This study investigated the degradation of nylon-6,6, PBS, and PHA-containing PBS filaments (PHA10 and PHA30) over a 54 week period in a marine environment. Molecular-weight analysis revealed considerable reductions in the PHA-containing samples, particularly PHA30, indicating higher susceptibility to microbial and hydrolytic degradation compared with PBS. Mechanical properties, such as tensile strength, elongation at break, and Young’s modulus, substantially declined for PHA blends. In contrast, PBS exhibited moderate degradation, while nylon-6,6 remained stable. Chemical analysis via FTIR and 1H NMR revealed ester bond cleavage in PBS and PHA blends, resulting in hydroxyl group formation and molecular breakdown. Microbial community analysis showed that PBS and PHA blends supported the growth of polyester-degrading bacteria, such as Rhodococcus, Pseudomonas, and Bacillus, while nylon-6,6 resisted microbial colonization. Overall, this study highlights the enhanced degradability of PHA-containing blends under marine conditions, making them suitable for environmentally friendly applications. In contrast, the stability of nylon-6,6 underscores the need for alternative materials in marine environments where rapid degradation is required.