Characteristics and polyethylene biodegradation function of a novel cold-adapted bacterial laccase from Antarctic sea ice psychrophile Psychrobacter sp. NJ228
Biotreatment of polyethylene (PE) waste is an emerging topic in environmental remediation; in particular, the degrading enzymes requires further exploration. This study described a novel cold-adapted laccase (PsLAC) from an Antarctic psychrophile and characterized its PE-degradation ability. Homology modeling revealed that PsLAC possessed a typical bacterial laccase catalytic structure and unique cold adaptation structural characteristics such as few hydrogen bonds . Recombinant PsLAC (rPsLAC) retained 54.3% residual activity at 0 ℃ and presented increased K m values at low temperatures and a relatively high k cat value (42.65 s −1 ). Collectively, these factors help resist cold stress. rPsLAC possessed substantial salt tolerance at 1.5 M NaCl, with 119.80% activity, and Cu 2+ enhanced its activity to 127.10%. PE-degradation experiments indicated that 13.2% weight was lost, and the water contact angle was decreased to 74.6°. Polar functional groups such as carbonyl and carboxyl groups on PE surface were detected in Fourier transform infrared spectroscopy ; X-ray diffraction exhibited that crystallinity reduced by 25%. Enormous damage to PE surface and interior was observed via scanning electron microscopy. Overall, PsLAC, with its unique cold-adapted catalytic structure and biochemical characteristics, could supplement the diversity of sources and properties of bacterial laccases and ensure PE-degradation with a novel cold-adapted enzyme resource.
危险品化学品经营许可证（带存储）