Ecole polytechnique de Sousse, département de genie-biotecnologie, Sousse, Tunisia.
Department for Sustainable Food Process, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
FEMS Microbiol Lett. 2020 Aug 1;367(15). doi: 10.1093/femsle/fnaa125.
Conventional plastics and bioplastics are known to accumulate in aquatic ecosystems, emerging as new surfaces for biofilm formation and gene exchanges. On the other hand, the fate of non-conventional bioplastics in the marine environment is still unclear. In this study we have measured, by means of crystal violet test and scanning electron microscopy (SEM), the ability of two model bacteria, Vibrio harveyi and Enterococcus faecalis, to form biofilms on low-density polyethylene (PE), polylactic acid (PLA) and starch-based bioplastic (SBB) surfaces. Experiments were conducted in artificial sea water, incubating squares of 3 cm2 of the three plastics with the two model microorganisms and sampling overnight, and at 3 and 6 days. The presence of biofilms on plastic surfaces was detected from day one of incubation and SBB was the material with the highest biofilm formation. E. faecalis formed the thickest biofilm after 3 days with PLA and SBB, but did not remain stable, and after 6 days with PE. The maximum biofilm formation of V. harveyi was obtained overnight with SBB and PE, and after 3 days with PLA. Our data indicate that both plastic and bioplastics support the formation of biofilms of model pathogenic bacteria, highlighting potential concerns for human health.
传统塑料和生物塑料已知会在水生生态系统中积累，成为生物膜形成和基因交换的新表面。另一方面，非常规生物塑料在海洋环境中的命运尚不清楚。在这项研究中，我们通过结晶紫试验和扫描电子显微镜（SEM）测量了两种模式细菌，即 Harveyi 弧菌和粪肠球菌，在低密度聚乙烯（PE）、聚乳酸（PLA）和淀粉基生物塑料（SBB）表面形成生物膜的能力。实验在人工海水中进行，用两种模式微生物孵育 3 厘米见方的三种塑料 6 天，并在第 1、3 和 6 天取样。从孵育的第一天开始，就在塑料表面检测到生物膜的存在，并且 SBB 是形成生物膜最多的材料。经过 3 天，粪肠球菌在 PLA 和 SBB 上形成了最厚的生物膜，但不稳定，而在 6 天在 PE 上。Harveyi 弧菌在 SBB 和 PE 上的最大生物膜形成是在一夜之间，在 PLA 上是在 3 天。我们的数据表明，塑料和生物塑料都支持模式致病性细菌生物膜的形成，这突出了对人类健康的潜在关注。
