Characteristics of cold-adapted arylesterase and low-temperature efficient PBAT degradation via cell surface display technology

The persistent accumulation of poly(butylene adipate-co-terephthalate) (PBAT) in the environment poses severe ecological threats. While enzymatic degradation offers promise, most reported enzymes require elevated reaction temperatures. Furthermore, free enzymes often suffer from limitations such as poor stability and high production costs. This study identified and characterized an innovative cold-adapted arylesterase (CsAE). CsAE exhibited optimum activity at 20℃ while retaining 48.77 % residual activity at 0℃, demonstrating characteristics of a cold-adapted enzyme. The engineered bacterium BL21/pET-INPN-CsAE, constructed via INPN surface display technology, exhibited normal growth while maintaining outer membrane integrity. Compared to the free CsAE, the whole-cell catalyst exhibited markedly enhanced thermal stability, reusability, and long-term operational stability. Notably, the observed features on the PBAT film—including the appearance of pores and cracks, a decrease in the water contact angle, cleavage of ester bonds, a reduction in the amorphous phase, and the emergence of the degradation monomer terephthalic acid—collectively indicate that both CsAE and the engineered strain facilitated the degradation of PBAT. Bioremediation experiments confirmed that the engineered strain mediated a 20.46 % degradation of PBAT over 21 days at 15℃, demonstrating its efficacy under low-temperature conditions. Collectively, this work establishes INPN-mediated surface display of the cold-adapted CsAE as a sustainable biocatalytic strategy for PBAT remediation in cold environments.