Division of Soil and Water Management, Department of Earth and Environmental Sciences, Faculty of Bioscience Engineering, KU Leuven, Kasteelpark Arenberg 20-bus 2459, B-3001, Heverlee, Belgium,
Appl Microbiol Biotechnol. 2014 Jan;98(2):931-43. doi: 10.1007/s00253-013-4928-4. Epub 2013 May 8.
Effects of environmental dissolved organic matter (eDOM) that consists of various low concentration carbonic compounds on pollutant biodegradation by bacteria are poorly understood, especially when it concerns synergistic xenobiotic-degrading consortia where degradation depends on interspecies metabolic interactions. This study examines the impact of the quality and quantity of eDOM, supplied as secondary C-source, on the structure, composition and pesticide-degrading activity of a triple-species bacterial consortium in which the members synergistically degrade the phenylurea herbicide linuron, when grown as biofilms. Biofilms developing on 10 mg L⁻¹ linuron showed a steady-state linuron degradation efficiency of approximately 85 %. The three bacterial strains co-localized in the biofilms indicating syntrophic interactions. Subsequent feeding with eDOM or citrate in addition to linuron resulted into changes in linuron-degrading activity. A decrease in linuron-degrading activity was especially recorded in case of co-feeding with citrate and eDOM of high quality and was always associated with accumulation of the primary metabolite 3,4-dichloroaniline. Improvement of linuron degradation was especially observed with more recalcitrant eDOM. Addition of eDOM/citrate formulations altered biofilm architecture and species composition but without loss of any of the strains and of co-localization. Compositional shifts correlated with linuron degradation efficiencies. When the feed was restored to only linuron, the linuron-degrading activity rapidly changed to the level before the mixed-substrate feed. Meanwhile only minor changes in biofilm composition and structure were recorded, indicating that observed eDOM/citrate effects had been primarily due to repression/stimulation of linuron catabolic activity rather than to biofilm characteristics.
环境溶解有机物 (eDOM) 由各种低浓度的碳酸化合物组成，其对细菌污染物生物降解的影响尚未被充分了解，特别是在涉及协同异生物质降解共生体的情况下，因为降解取决于种间代谢相互作用。本研究考察了作为次生 C 源供应的 eDOM 的质量和数量对三重细菌共生体结构、组成和农药降解活性的影响，该共生体以生物膜形式协同降解苯基脲除草剂敌草隆。在 10mg/L 敌草隆的生物膜上，生物膜的稳态敌草隆降解效率约为 85%。三种细菌菌株在生物膜中共定位，表明存在协同作用。随后，在添加敌草隆的基础上添加 eDOM 或柠檬酸盐，会导致敌草隆降解活性发生变化。特别是在共添加高质量的柠檬酸盐和 eDOM 的情况下，观察到敌草隆降解活性明显下降，并且总是伴随着主要代谢物 3,4-二氯苯胺的积累。与添加更难降解的 eDOM 相比，敌草隆降解得到了明显改善。添加 eDOM/柠檬酸盐配方会改变生物膜结构和物种组成，但不会损失任何一种菌株或共定位。组成变化与敌草隆降解效率相关。当饲料恢复仅为敌草隆时，敌草隆降解活性迅速恢复到混合底物喂养前的水平。与此同时，生物膜组成和结构仅发生了较小的变化，这表明观察到的 eDOM/柠檬酸盐的影响主要是由于敌草隆分解代谢活性的抑制/刺激，而不是生物膜特性。
