Characterization of Newly Discovered Polyester Polyurethane-degrading Methylobacterium Aquaticum Strain A1

ABSTRACT In this study, we present Methylobacterium aquaticum A1, a novel strain capable of degrading polyester polyurethane (PE-PUR). The attachment of M. aquaticum A1 to PE-PUR and its degradation capabilities were verified using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FT-IR). Analysis of the reference genome of M. aquaticum revealed genes encoding enzymes with potential PE-PUR degrading activity, including esterases, lipase, proteases and amidase such as tesA , pgpB , aes , aprE , lon , degQ, and gatA . An esterase activity assay using p -nitrophenyl acetate ( p -NPA) showed increased ester bond-cleaving activity when M. aquaticum A1 was exposed to polyurethane diol (PU-diol), suggesting inducible enzymatic activity involved in PE-PUR degradation. These findings highlight the potential of M. aquaticum A1 as a promising biocatalyst for PE-PUR degradation. IMPORTANCE Microbial biodegradation is increasingly recognized as a sustainable approach to addressing microplastic pollution. This study introduces M. aquaticum A1, a newly isolated strain capable of adhering to and degrading polyester polyurethane (PE-PUR), one of the most widely utilized plastics. To our knowledge, this is the first report of PE-PUR degradation by a member of the Methylobacterium genus. This paper provides a detailed characterization of M. aquaticum A1 and identifies several enzyme candidates— tesA , pgpB , aes , aprE , lon , degQ, and gatA —as potentially involved in the degradation process. Given that Methylobacterium species are known to be ecologically beneficial and inhabit diverse environments, the capacity of M. aquaticum A1 to degrade PE-PUR presents a promising strategy for mitigating microplastic pollution across a range of ecosystems.