National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian 271018, Shandong, China.
Shandong Provincial Eco-Environment Monitoring Center, Jinan 250101, China.
J Hazard Mater. 2024 May 15;470:134176. doi: 10.1016/j.jhazmat.2024.134176. Epub 2024 Mar 31.
Biodegradable microplastics (MPs) are promising alternatives to conventional MPs and are of high global concern. However, their discrepant effects on soil microorganisms and functions are poorly understood. In this study, polyethylene (PE) and polylactic acid (PLA) MPs were selected to investigate the different effects on soil microbiome and C-cycling genes using high-throughput sequencing and real-time quantitative PCR, as well as the morphology and functional group changes of MPs, using scanning electron microscopy and Fourier transform infrared spectroscopy, and the driving factors were identified. The results showed that distinct taxa with potential for MP degradation and nitrogen cycling were enriched in soils with PLA and PE, respectively. PLA, smaller size (150-180 µm), and 5% (w/w) of MPs enhanced the network complexity compared with PE, larger size (250-300 µm), and 1% (w/w) of MPs, respectively. PLA increased β-glucosidase by up to 2.53 times, while PE (150-180 µm) reduced by 38.26-44.01% and PE (250-300 µm) increased by 19.00-22.51% at 30 days. Amylase was increased by up to 5.83 times by PLA (150-180 µm) but reduced by 40.26-62.96% by PLA (250-300 µm) and 16.11-43.92% by PE. The genes cbbL, cbhI, abfA, and Lac were enhanced by 37.16%- 1.99 times, 46.35%- 26.46 times, 8.41%- 69.04%, and 90.81%- 5.85 times by PLA except for PLA1B/5B at 30 days. These effects were associated with soil pH, NO-N, and MP biodegradability. These findings systematically provide an understanding of the impact of biodegradable MPs on the potential for global climate change.
可生物降解微塑料（MPs）是传统 MPs 的有前途的替代品，受到全球高度关注。然而，它们对土壤微生物和功能的不同影响还知之甚少。在这项研究中，选择了聚乙烯（PE）和聚乳酸（PLA） MPs，通过高通量测序和实时定量 PCR 研究它们对土壤微生物组和 C 循环基因的不同影响，以及使用扫描电子显微镜和傅里叶变换红外光谱观察 MPs 的形态和功能基团变化，并确定了驱动因素。结果表明，在含有 PLA 和 PE 的土壤中，分别富集了具有潜在 MP 降解和氮循环能力的不同分类群。与 PE（较大尺寸（250-300μm）和 1%（w/w）的 MPs）相比，PLA（较小尺寸（150-180μm）和 5%（w/w）的 MPs）分别增强了网络的复杂性。PLA 使β-葡萄糖苷酶增加了 2.53 倍，而 PE（150-180μm）在 30 天内降低了 38.26-44.01%，PE（250-300μm）增加了 19.00-22.51%。PLA（150-180μm）使淀粉酶增加了 5.83 倍，但 PLA（250-300μm）降低了 40.26-62.96%，PE 降低了 16.11-43.92%。cbbL、cbhI、abfA 和 Lac 基因在 30 天时分别增强了 37.16%-1.99 倍、46.35%-26.46 倍、8.41%-69.04%和 90.81%-5.85%，但 PLA1B/5B 除外。这些影响与土壤 pH、NO-N 和 MP 可生物降解性有关。这些发现系统地提供了对可生物降解 MPs 对全球气候变化潜力影响的理解。
