Department of Microbiology, University of Lagos, Akoka, Lagos, Nigeria; Department of Microbiology, Lagos State University, Ojo, Lagos, Nigeria.
Department of Microbiology, University of Lagos, Akoka, Lagos, Nigeria.
J Hazard Mater. 2023 Jun 5;451:131105. doi: 10.1016/j.jhazmat.2023.131105. Epub 2023 Feb 28.
A pristine soil was artificially contaminated with 2-chlorodibenzo-p-dioxin (2-CDD) and separated into three portions. Microcosms SSOC and SSCC were seeded with Bacillus sp. SS2 and a three-member bacterial consortium respectively; SSC was untreated, while heat-sterilized contaminated soil served as overall control. Significant degradation of 2-CDD occurred in all microcosms except for the control where the concentration remained unchanged. Degradation of 2-CDD was highest in SSCC (94.9%) compared to SSOC (91.66%) and SCC (85.9%). There was also a notable reduction in the microbial composition complexity both in species richness and evenness following dioxin contamination, a trend that nearly lasted the study period; particularly in setups SSC and SSOC. Irrespective of the bioremediation strategies, the soil microflora was practically dominated by the Firmicutes and at the genus level, the phylotype Bacillus was the most dominant. Other dominant taxa though negatively impacted were Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria. Overall, this study demonstrated the feasibility of microbial seeding as an effective strategy to cleanup tropical soil contaminated with dioxins and the importance of metagenomics in elucidating the microbial diversities of contaminated soils. Meanwhile, the seeded organisms, owed their success not only to metabolic competence, but survivability, adaptability and ability to compete favourably with autochthonous microflora.
一份原始土壤被人为地用 2-氯二苯并对二恶英（2-CDD）污染，并分为三部分。微宇宙 SSOC 和 SSCC 分别接种了芽孢杆菌 SS2 和一个由三个成员组成的细菌联合体；SSC 未处理，而热灭菌污染土壤作为总对照。除了浓度保持不变的对照外，所有微宇宙中都发生了 2-CDD 的显著降解。与 SSOC（91.66%）和 SCC（85.9%）相比，SSCC 中 2-CDD 的降解最高（94.9%）。在二恶英污染后，微生物组成的复杂性，无论是在物种丰富度还是均匀度方面，都有明显的降低，这种趋势几乎持续了整个研究期；特别是在 SSC 和 SSOC 这两个设置中。无论采用何种生物修复策略，土壤微生物群实际上都由厚壁菌门（Firmicutes）主导，在属水平上，芽孢杆菌（Bacillus）是最主要的优势菌属。其他优势菌群虽然受到负面影响，但仍属于变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、绿弯菌门（Chloroflexi）和酸杆菌门（Acidobacteria）。总的来说，这项研究表明，微生物接种作为一种有效策略来清理受二恶英污染的热带土壤是可行的，同时宏基因组学在阐明污染土壤的微生物多样性方面也具有重要意义。同时，接种的生物不仅得益于其代谢能力，还得益于其生存能力、适应性以及与土著微生物竞争的能力。
