Division of Water, Environment, Process and Analyses (DEPA), BRGM, The French Geological Survey, 3 Avenue Claude Guillemin, 45100, Orléans, France.
CNRS, INSA CVL, GREMAN UMR 7347, IUT de Blois, GREMAN, University of Tours, 15 Rue de la Chocolaterie, 41029, Blois, France.
Environ Sci Pollut Res Int. 2021 Sep;28(33):45296-45316. doi: 10.1007/s11356-021-13876-9. Epub 2021 Apr 16.
The development of biofilms on modified natural zeolites was investigated with purpose to obtain biocomposites with biodegradation activity towards pesticides MCPA (2-methyl-4-chlorophenoxyacetic acid) and glyphosate (N-(phosphonomethyl)glycine) for potential application in bioaugmentation of polluted agricultural soils. Microbial communities were selected from agricultural pesticide-contaminated soil/water samples and enriched on the basis of their ability to biodegrade the pesticides. In order to enhance affinity of microbial communities to the support material, the natural mineral zeolite was modified by nontoxic environmentally friendly cations (Li, Na, K, NH, H, Mg, Ca, Fe) by methods preserving its structure and characterised using powder XRD, surface area measurement and chemical composition analysis. Kinetics of pesticide degradation by the biocomposites was studied in liquid media. Results showed that according to zeolite modifications, the microbial activity and biodiversity changed. The best biodegradation rate of MCPA and glyphosate reached 0.12-0.13 mg/h with half-life of 16-18 h, which is considerably quicker than observed in natural environment. However, in some cases, biodegradation activity towards pesticides was lost which was connected to unfavourable zeolite modification and accumulation of toxic metabolites. High-throughput sequencing on the 16S rRNA genes of the biofilm communities highlighted the selection of bacteria genera known to metabolise MCPA (Aminobacter, Cupriavidus, Novosphingobium, Pseudomonas, Rhodococcus, Sphingobium and Sphingopyxis) and glyphosate (Pseudomonas). Altogether, results suggested that zeolites do not only have a passive role of biofilm support but also have protective and nutrient-supportive functions that consequently increase biodiversity of the pesticide degraders growing in the biofilm and influence the pesticide biodegradation rate.
研究了改性天然沸石上生物膜的发展，目的是获得具有生物降解 MCPA（2-甲基-4-氯苯氧乙酸）和草甘膦（N-（膦酸甲基）甘氨酸）活性的生物复合材料，用于污染农业土壤的生物增强。从农业农药污染土壤/水样中选择微生物群落，并根据其生物降解农药的能力进行富集。为了增强微生物群落对支撑材料的亲和力，通过不使用有毒环保阳离子（Li、Na、K、NH、H、Mg、Ca、Fe）改性天然矿物质沸石，方法保持其结构并使用粉末 XRD、表面积测量和化学组成分析进行表征。在液体介质中研究了生物复合材料对农药的降解动力学。结果表明，根据沸石的改性，微生物的活性和生物多样性发生了变化。MCPA 和草甘膦的最佳生物降解率达到 0.12-0.13mg/h，半衰期为 16-18h，这比在自然环境中观察到的要快得多。然而，在某些情况下，生物降解活性丧失与不利的沸石改性和有毒代谢物的积累有关。生物膜群落的 16S rRNA 基因高通量测序突出了代谢 MCPA（Aminobacter、Cupriavidus、Novosphingobium、Pseudomonas、Rhodococcus、Sphingobium 和 Sphingopyxis）和草甘膦（Pseudomonas）的细菌属的选择。总的来说，结果表明沸石不仅具有生物膜支撑的被动作用，而且还具有保护和营养支持功能，这会增加生物膜中生长的农药降解菌的生物多样性，并影响农药的生物降解率。
