Muangchinda Chanokporn, Naloka Kallayanee, Pinyakong Onruthai
International Postgraduate Programs in Hazardous Substance and Environmental Management, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand; Center of Excellence in Microbial Technology for Marine Pollution Treatment (MiTMaPT), Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Center of Excellence in Microbial Technology for Marine Pollution Treatment (MiTMaPT), Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Sci Total Environ. 2025 Jul 31;996:180131. doi: 10.1016/j.scitotenv.2025.180131.
Low-density polyethylene (LDPE) is a persistent plastic that significantly contributes to environmental pollution. Although individual bacterial strains show limited ability to degrade LDPE, synthetic consortia present a promising alternative. This study constructed a synthetic bacterial consortium (GAM), comprising Gordonia sihwensis LS1, Amycolatopsis thermoflava 3B14, and Mesorhizobium sp. 1B3, selected for their complementary traits in LDPE degradation, biofilm formation, biosurfactant production, and nonpathogenic profiles. In liquid culture, the GAM consortium exhibited a higher LDPE degradation rate (0.0007 day) than individual strains (0.0005-0.0006 day), based on a pseudo-first-order kinetic model. The consortium was then applied to soil microcosms. To enhance biodegradability, visible light exposure and deep eutectic solvent (DES) coating were applied alone or combined with bioaugmentation. After 60 days, LDPE weight loss in GAM-treated microcosms ranged from 5.70 % to 7.88 %, compared to 1.66 %-2.37 % in uninoculated microcosms. The LDPE half-life decreased from 1731-2482 days to 504-705 days with consortium inoculation. The greatest degradation occurred when bioaugmentation was combined with both light and DES, with significant differences confirmed statistically (p ≤ 0.05). Scanning electron microscopy and Fourier-transform infrared spectroscopy revealed surface cracking and reduced peak intensities, indicating polymer breakdown. Bacterial community analysis showed the consortium members remained abundant with minimal impact on native microbiota. Genomic analysis identified genes related to LDPE degradation, biofilm formation, and biosurfactant production; however, transcriptomic or proteomic validation is needed to confirm gene expression. These results highlight the GAM consortium's enhanced LDPE degradation potential and the benefit of integrating microbial and physicochemical approaches for plastic waste mitigation.
低密度聚乙烯（LDPE）是一种持久性塑料，对环境污染有重大影响。尽管个别细菌菌株降解LDPE的能力有限，但合成菌群提供了一种有前景的替代方案。本研究构建了一个合成细菌菌群（GAM），它由嗜温戈登氏菌LS1、嗜热栖热放线菌3B14和中生根瘤菌属1B3组成，这些菌株因其在LDPE降解、生物膜形成、生物表面活性剂产生和无致病特性方面的互补特性而被选中。在液体培养中，基于伪一级动力学模型，GAM菌群表现出比单个菌株（0.0005 - 0.0006天）更高的LDPE降解率（0.0007天）。然后将该菌群应用于土壤微观生态系统。为了提高生物降解性，单独或与生物强化相结合应用了可见光照射和深共晶溶剂（DES）涂层。60天后，经GAM处理的微观生态系统中LDPE的重量损失在5.70%至7.88%之间，而未接种的微观生态系统中为1.66% - 2.37%。接种菌群后，LDPE的半衰期从1731 - 2482天降至504 - 705天。当生物强化与光照和DES同时结合时，降解效果最佳，经统计学确认有显著差异（p≤0.05）。扫描电子显微镜和傅里叶变换红外光谱显示表面开裂和峰强度降低，表明聚合物发生了分解。细菌群落分析表明，菌群成员数量保持丰富，对本地微生物群的影响最小。基因组分析确定了与LDPE降解、生物膜形成和生物表面活性剂产生相关的基因；然而，需要转录组学或蛋白质组学验证来确认基因表达。这些结果突出了GAM菌群增强的LDPE降解潜力，以及整合微生物和物理化学方法减轻塑料废物的益处。
