Bioelectrochemical enhancement of polybutylene succinate degradation via electricity-supplemented engineered Shewanella oneidensis MR-1.

Although biodegradable plastics have been developed to mitigate the environmental impact of conventional plastics, their timely degradation remains challenging. In this study, we aimed to accelerate the degradation of bioplastics using an electricity-assisted approach by engineering Shewanella oneidensis MR-1 to express triacylglycerol lipase (TGL) from Bacillus sp. JY35. The engineered strain was evaluated for its ability to degrade bioplastics, such as polybutylene succinate (PBS), polycaprolactone (PCL), and polybutylene adipate terephthalate (PBAT). Clear zone assays confirmed the degradation activity of the engineered strain, which was absent in wild-type S. oneidensis MR-1. PBS film degradation was assessed under aerobic conditions, as well as in microbial fuel cells (MFCs) and bioelectrochemical systems (BESs) under microaerobic conditions. The engineered strain exhibited 4.2 % degradation under aerobic conditions and 24.7 % degradation after 14 days of MFC operation, compared with no measurable degradation by the wild-type strain. Notably, BES operation with external electron supply further enhanced PBS degradation, achieving a 41.2 % degradation yield. These results highlight the potential of bioelectrochemical strategies for promoting bioplastic degradation through electron supplementation to engineered electrogens.