School of Biology and Biological Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Panyu District, Guangzhou, 510006, China.
Mol Biol Rep. 2023 Oct;50(10):8523-8535. doi: 10.1007/s11033-023-08712-x. Epub 2023 Aug 29.
Polyvinyl alcohol (PVA) is one of the most widely used water-soluble polymers with remarkable mechanical properties. However, water-soluble polymers are among the major organic pollutants of streams, river, and marine ecosystems. Once dispersed in aqueous systems, they can directly interfere with the life cycle of aquatic organisms via direct toxic effects. There is thus an urgent need for microorganisms or enzymes that can efficiently degrade them. Oxidized PVA hydrolase plays an important role in the pathway of PVA biodegradation. It is the key enzyme in the second step of the pathway for complete degradation of PVA.
The s-oph gene was cloned from the laboratory-isolated strain Sphingopyxis sp. M19. This gene was expressed in the Escherichia coli system pET32a/s-oph expression vector, with the products forming an inclusion body. By binding with a molecular chaperone, pET32a/s-oph/BL21 (DE3)/pGro7 was successfully constructed, which enabled the s-oph gene to be solubly expressed in E. coli. The protein encoded by the s-oph gene was purified at a yield of 16.8 mg L, and its catalytic activity reached 852.71 U mg. In the s-oph enzyme reaction system, the efficiency of PVA degradation was increased to 233.5% compared with that of controls.
The s-oph enzyme exhibited the characteristics of being able to degrade PVA with high efficiency, specificity, and stability. This enzyme has good potential for practical application in ameliorating plastic pollution and protecting the environment.
聚乙烯醇（PVA）是一种用途最广泛的水溶性聚合物，具有显著的机械性能。然而，水溶性聚合物是溪流、河流和海洋生态系统中主要的有机污染物之一。一旦分散在水系统中，它们可以通过直接的毒性作用直接干扰水生生物的生命周期。因此，迫切需要能够有效降解它们的微生物或酶。氧化聚乙烯醇水解酶在 PVA 生物降解途径中发挥着重要作用。它是 PVA 完全降解途径中第二步的关键酶。
s-oph 基因从实验室分离的菌株鞘氨醇单胞菌 sp. M19 中克隆得到。该基因在大肠杆菌表达载体 pET32a/s-oph 中表达，产物形成包涵体。通过与分子伴侣结合，成功构建了 pET32a/s-oph/BL21（DE3）/pGro7，使 s-oph 基因在大肠杆菌中可溶表达。s-oph 基因编码的蛋白质的产量为 16.8 mg L，其催化活性达到 852.71 U mg。在 s-oph 酶反应体系中，与对照相比，PVA 降解效率提高了 233.5%。
s-oph 酶表现出高效、特异性和稳定性降解 PVA 的特点。该酶在改善塑料污染和保护环境方面具有良好的实际应用潜力。
