Abstract：
As the ecological niche most closely associated with polymers, microorganisms in the \'plastisphere\' have great potential for plastics degradation. Microorganisms isolated from the \'plastisphere\' could colonize and degrade commercial plastics containing different additives, but the observed weight loss and surface changes were most likely caused by releasing the additives rather than actual degradation of the plastics itself. Unlike commercial plastics that contain additives, whether marine microorganisms in the \'plastisphere\' have adapted to additive-free plastics as a surface to colonize and potentially degrade is not yet known. Herein, a novel marine bacterium, Exiguobacterium marinum a-1, was successfully isolated from mature \'plastisphere\' that had been deployed in situ for up to 20 months. Strain a-1 could use additive-free polypropylene (PP) films as its primary energy and carbon source. After strain a-1 was incubated with additive-free PP films for 80 days, the weight of films decreased by 9.2%. The ability of strain a-1 to rapidly form biofilms and effectively colonize the surface of additive-free PP films was confirmed by Scanning Electron Microscopy (SEM), as reflected by the increase in roughness and visible craters on the surface of additive-free PP films. Additionally, the functional groups of -CO, -C-H, and -OH were identified on the treated additive-free PP films according to Fourier Transform Infrared (FTIR). Genomic data from strain a-1 revealed a suite of key genes involved in biosurfactant synthesis, flagellar assembly, and cellular chemotaxis, contributing to its rapid biofilm formation on hydrophobic polymer surfaces. In particular, key enzymes that may be responsible for the degradation of additive-free PP films, such as glutathione peroxidase, cytochrome p450 and esterase were also recognized. This study highlights the potential of microorganisms present in the \'plastisphere\' to metabolize plastic polymers and points to the intrinsic importance of the new strain a-1 in the mitigation of plastic pollution.
摘要：
作为与聚合物最密切相关的生态位，“质体中的微生物具有很大的塑料降解潜力。从“质体”分离的微生物可以定殖和降解含有不同添加剂的商业塑料，但是观察到的重量损失和表面变化很可能是由释放添加剂而不是塑料本身的实际降解引起的。与含有添加剂的商业塑料不同，目前尚不清楚“质体中的海洋微生物是否已适应无添加剂塑料作为定植和潜在降解的表面。在这里，一种新的海洋细菌，Marinuma-1原细菌已成功从已原位部署长达20个月的成熟“质体”中分离出来。菌株a-1可以使用无添加剂的聚丙烯（PP）薄膜作为其主要能源和碳源。菌株a-1与无添加剂的PP膜孵育80天后，薄膜的重量减少了9.2%。通过扫描电子显微镜（SEM）证实了菌株a-1快速形成生物膜并有效定植无添加剂PP膜表面的能力，如无添加剂PP薄膜表面粗糙度和可见凹陷的增加所反映的。此外,-CO的官能团，-C-H,根据傅里叶变换红外(FTIR)在处理过的无添加剂PP膜上鉴定出-OH。来自菌株a-1的基因组数据揭示了一系列参与生物表面活性剂合成的关键基因，鞭毛组装，和细胞趋化性，有助于其在疏水性聚合物表面上快速形成生物膜。特别是,可能导致无添加剂PP薄膜降解的关键酶，如谷胱甘肽过氧化物酶，细胞色素p450和酯酶也被识别。这项研究强调了“质体球”中存在的微生物代谢塑料聚合物的潜力，并指出了新菌株a-1在缓解塑料污染方面的内在重要性。
