Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, 73140, Thailand.
Microbial Biotechnology Unit, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, 73140, Thailand.
Folia Microbiol (Praha). 2022 Aug;67(4):659-669. doi: 10.1007/s12223-022-00964-7. Epub 2022 Apr 6.
Poly(ε-caprolactone; PCL) is an attractive biodegradable polymer that has been increasingly used to solve environmental problems caused by plastic wastes. In the present study, 468 bacterial isolates were recovered from soil samples and screened for PCL degradation activity. Of the isolates, 37 (7.9%) showed PCL depolymerase activity on PCL agar medium, with the highest activity being by isolate S22 which was identified using 16S rRNA and rpoB gene sequencing as Acinetobacter seifertii. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed the degradation of PCL films after treatment with A. seifertii S22. The PCL depolymerase activity of A. seifertii S22 relied on the activity of esterase which occurred at an optimum temperature of 30-40 °C. The highest PCL depolymerase activity (35.5 ± 0.7 U/mL) was achieved after culturing A. seifertii S22 for 6 h in mineral salt medium (MSM) containing 0.1% Tween 20 and 0.02% ammonium sulfate as the carbon and nitrogen sources, respectively, which was approximately 20-fold higher than for cultivation in MSM supplemented with 0.1% PCL as sole carbon source. The results suggested that A. seifertii S22 or its enzymes could be used for PCL bioplastic degradation.
聚己内酯（PCL）是一种有吸引力的可生物降解聚合物，已越来越多地被用于解决塑料废物造成的环境问题。在本研究中，从土壤样品中回收了 468 株细菌分离物，并对其进行了 PCL 降解活性筛选。在这些分离物中，有 37 株（7.9%）在 PCL 琼脂培养基上显示出 PCL 解聚酶活性，其中活性最高的是分离物 S22，通过 16S rRNA 和 rpoB 基因测序鉴定为不动杆菌属。扫描电子显微镜和傅里叶变换红外光谱证实了 A. seifertii S22 处理后的 PCL 薄膜的降解。A. seifertii S22 的 PCL 解聚酶活性依赖于酯酶的活性，其最适温度为 30-40°C。当在含有 0.1%吐温 20 和 0.02%硫酸铵的无机盐培养基（MSM）中培养 A. seifertii S22 6 小时时，获得了最高的 PCL 解聚酶活性（35.5±0.7 U/mL），分别作为碳源和氮源，这大约是在补充有 0.1% PCL 作为唯一碳源的 MSM 中培养时的 20 倍。结果表明，A. seifertii S22 或其酶可用于 PCL 生物塑料的降解。
