Low-density polyethylene (LDPE) polymer is mainly used in the production of plastic bags and food packaging making up the largest volume of plastic pollutions. These polymers are potential substrates for bacteria in the bioremediation process. In this study, soil samples were collected from different plastic landfills in Iran and subsequently enriched in specific media (polyethylene as carbon source) to increase the population of LDPE-degrading bacteria. Seventeen PE-degrading bacteria, some novel, were isolated from Iranian soil samples and identified using 16S rDNA gene sequencing. These isolates were capable of degrading PE in a limited incubation period without the need for physicochemical pretreatments and comprise mostly of Actinobacteria which include the three genera of Streptomyces, Nocardia, and Rhodococcus. The isolates belonged to 17 different species of gram-positive Actinobacteria. In all, 11 species of the genus Streptomyces, 3 species of the genus Rhodococcus, and 3 species of the genus Nocardia were identified. The isolates with less than 99% 16S rRNA gene similarity to previously known species were suspected to be new species. Various analyses (weight loss, SEM, FTIR, and tensile strength test) to determine polyethylene biodegradation rate were carried out after a 60-day incubation period. Analysis of polyethylene biodegradation elucidates that Actinobacteria have a high ability for biodegradation of polyethylene-based plastics. Streptomyces sp. IR-SGS-T10 showed the highest reduction in weight of the LDPE film (1.58 mg/g/day) after 60 days of incubation without any pretreatments. Rhodococcus sp. IR-SGS-T11 shows the best reduction in the tensile property of LDPE film, while results from FTIR study for Streptomyces sp. IR-SGS-Y1 indicated a significant change in structural analysis.

低密度聚乙烯 (LDPE) 聚合物主要用于生产塑料袋和食品包装，构成塑料污染的最大量。这些聚合物是生物修复过程中细菌的潜在底物。在这项研究中，土壤样本是从伊朗不同的塑料垃圾填埋场收集的，随后在特定介质（聚乙烯作为碳源）中富集，以增加 LDPE 降解细菌的数量。从伊朗土壤样本中分离出 17 种降解 PE 的细菌，其中一些是新型细菌，并使用 16S rDNA 基因测序进行鉴定。这些分离物能够在有限的潜伏期内降解 PE 而不需要物理化学预处理，并且主要由放线菌组成，包括链霉菌属的三个属，诺卡氏菌和红球菌。这些分离株属于 17 种不同种类的革兰氏阳性放线菌。总共鉴定出链霉菌属 11 种、红球菌属3 种和诺卡氏菌属3 种。与先前已知物种的 16S rRNA 基因相似性低于 99% 的分离株被怀疑是新物种。在 60 天的培养期后，进行了各种分析（重量损失、SEM、FTIR 和拉伸强度测试）以确定聚乙烯的生物降解率。聚乙烯生物降解分析表明，放线菌对聚乙​​烯基塑​​料的生物降解能力很强。链霉菌属IR-SGS-T10在没有任何预处理的情况下培养 60 天后，显示出 LDPE 薄膜重量的最大减少（1.58 毫克/克/天）。红球菌属 IR-SGS-T11 显示出 LDPE 薄膜拉伸性能的最佳降低，而链霉菌属的FTIR 研究结果。IR-SGS-Y1 表明结构分析发生了显着变化。