Enhancing PET biocatalytic degradation using a surface-active metabolite formulation derived from Trichoderma asperellum PBW1.

Polyethylene terephthalate (PET) pollution necessitates biotechnological strategies that enhance interaction between the hydrophobic surfaces of PET and microbial biocatalysts. In this study, we developed PBW1-SAMF, an operationally defined autoclaved surface-active metabolite formulation derived from Trichoderma asperellum PBW1, which was isolated from plastic-contaminated mangrove sediments in Malaysia. The analyses conducted using liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy suggested that PBW1-SAMF is a lipid-rich, multicomponent formulation containing surface-active and bioemulsifier-like constituents. However, blank-overlapping LC-MS features were excluded from PBW1-specific interpretation. PBW1-SAMF was evaluated in two PET biocatalytic systems: a PET-degrading yeast-like fungus, Geotrichum sp. ETG, and a recombinant Escherichia coli whole-cell biocatalyst expressing Ester7845. In the fungal system, PBW1-SAMF increased terephthalic acid (TPA) release by approximately 3.8-fold in comparison with the ETG-only control. In the recombinant bacterial system, PBW1-SAMF increased blank-corrected TPA release by approximately 80-fold in comparison with the whole-cell control, although the absolute unit-corrected apparent PET-equivalent conversion remained low. PBW1-SAMF also showed stronger enhancement than the tested commercial biosurfactant treatments under the present recombinant whole-cell reaction conditions. Contact angle, CFU enumeration, extracellular OD260/OD280 leakage assessment, and inhibition-zone assays supported improved PET wettability and whole-cell compatibility. In summary, PBW1-SAMF is a multicomponent formulation-level enhancer derived from fermentation, which increases soluble PET-derived product release. However, further formulation standardisation, mechanistic validation, and complete mass-balance analysis are required to further investigate its efficacy.