Fujian Key Laboratory of Pollution Control & Resource Reuse, College of Environmental and Resource Sciences, Fujian Normal University, Fuzhou, 350007, China.
State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
Microbiome. 2024 Feb 29;12(1):43. doi: 10.1186/s40168-023-01741-5.
Bioaugmentation has the potential to enhance the ability of ecological technology to treat sulfonamide-containing wastewater, but the low viability of the exogenous degraders limits their practical application. Understanding the mechanism is important to enhance and optimize performance of the bioaugmentation, which requires a multifaceted analysis of the microbial communities. Here, DNA-stable isotope probing (DNA-SIP) and metagenomic analysis were conducted to decipher the bioaugmentation mechanisms in stabilization pond sediment microcosms inoculated with sulfamethoxazole (SMX)-degrading bacteria (Pseudomonas sp. M2 or Paenarthrobacter sp. R1).
The bioaugmentation with both strains M2 and R1, especially strain R1, significantly improved the biodegradation rate of SMX, and its biodegradation capacity was sustainable within a certain cycle (subjected to three repeated SMX additions). The removal strategy using exogenous degrading bacteria also significantly abated the accumulation and transmission risk of antibiotic resistance genes (ARGs). Strain M2 inoculation significantly lowered bacterial diversity and altered the sediment bacterial community, while strain R1 inoculation had a slight effect on the bacterial community and was closely associated with indigenous microorganisms. Paenarthrobacter was identified as the primary SMX-assimilating bacteria in both bioaugmentation systems based on DNA-SIP analysis. Combining genomic information with pure culture evidence, strain R1 enhanced SMX removal by directly participating in SMX degradation, while strain M2 did it by both participating in SMX degradation and stimulating SMX-degrading activity of indigenous microorganisms (Paenarthrobacter) in the community.
Our findings demonstrate that bioaugmentation using SMX-degrading bacteria was a feasible strategy for SMX clean-up in terms of the degradation efficiency of SMX, the risk of ARG transmission, as well as the impact on the bacterial community, and the advantage of bioaugmentation with Paenarthrobacter sp. R1 was also highlighted. Video Abstract.
生物强化有可能增强生态技术处理含磺胺类抗生素废水的能力，但外源性降解菌的低存活率限制了其实际应用。了解机制对于增强和优化生物强化性能很重要，这需要对微生物群落进行多方面的分析。在这里，采用 DNA 稳定同位素探针（DNA-SIP）和宏基因组分析方法，解析了接种磺胺甲恶唑（SMX）降解菌（假单胞菌 M2 或节杆菌 R1）的稳定塘沉积物微宇宙中的生物强化机制。
两种菌株 M2 和 R1 的生物强化，特别是菌株 R1，显著提高了 SMX 的生物降解率，并且在一定的循环内（经过三次重复添加 SMX）其生物降解能力是可持续的。使用外源降解菌的去除策略也显著减少了抗生素抗性基因（ARGs）的积累和传播风险。接种 M2 菌株显著降低了细菌多样性并改变了沉积物细菌群落，而接种 R1 菌株对细菌群落的影响较小，与土著微生物密切相关。基于 DNA-SIP 分析，鉴定节杆菌为两种生物强化系统中主要的 SMX 同化菌。结合基因组信息和纯培养证据，R1 菌株通过直接参与 SMX 降解增强了 SMX 的去除，而 M2 菌株则通过参与 SMX 降解和刺激群落中土著微生物（节杆菌）的 SMX 降解活性来实现 SMX 的去除。
我们的研究结果表明，就 SMX 的降解效率、ARGs 传播风险以及对细菌群落的影响而言，使用 SMX 降解菌进行生物强化是一种可行的 SMX 净化策略，并且还突出了节杆菌 R1 菌株在生物强化中的优势。
