Laboratory of Wastewater Management and Treatment Technologies, Department of Environmental Engineering, Democritus University of Thrace, Vas. Sofias 12, 67132, Xanthi, Greece.
Laboratory of Plant and Environmental Biotechnology, Department of Biochemistry and Biotechnology, University of Thessaly, Viopolis, 41500, Larissa, Greece.
Environ Sci Pollut Res Int. 2022 Apr;29(20):29597-29612. doi: 10.1007/s11356-021-16452-3. Epub 2021 Sep 20.
Fludioxonil is a post-harvest fungicide contained in effluents produced by fruit packaging plants, which should be treated prior to environmental dispersal. We developed and evaluated an immobilized cell bioreactor, operating under microaerophilic conditions and gradually reduced hydraulic retention times (HRTs) from 10 to 3.9 days, for the biotreatment of fludioxonil-rich wastewater. Fludioxonil removal efficiency was consistently above 96%, even at the shortest HRT applied. A total of 12 transformation products were tentatively identified during fludioxonil degradation by using liquid chromatography coupled to quadrupole time-of-flight Mass spectrometry (LC-QTOF-MS). Fludioxonil degradation pathway was initiated by successive hydroxylation and carbonylation of the pyrrole moiety and disruption of the oxidized cyanopyrrole ring at the NH-C bond. The detection of 2,2-difluoro-2H-1,3-benzodioxole-4-carboxylic acid verified the decyanation and deamination of the molecule, whereas its conversion to the tentatively identified compound 2,3-dihydroxybenzoic acid indicated its defluorination. High-throughput amplicon sequencing revealed that HRT shortening led to reduced α-diversity, significant changes in the β-diversity, and a shift in the bacterial community composition from an initial activated sludge system typical community to a community composed of bacterial taxa like Clostridium, Oligotropha, Pseudomonas, and Terrimonas capable of performing advanced degradation and/or aerobic denitrification. Overall, the immobilized cell bioreactor operation under microaerophilic conditions, which minimizes the cost for aeration, can provide a sustainable solution for the depuration of fludioxonil-contaminated agro-industrial effluents.
氟啶酮是一种在水果包装厂产生的废水中含有的收获后杀菌剂，在环境扩散之前应进行处理。我们开发并评估了一种固定化细胞生物反应器，在微需氧条件下运行，并逐渐将水力停留时间（HRT）从 10 天缩短至 3.9 天，用于富含氟啶酮的废水的生物处理。即使在应用的最短 HRT 下，氟啶酮的去除效率也始终保持在 96%以上。通过使用液相色谱-四极杆飞行时间质谱联用（LC-QTOF-MS）对氟啶酮降解过程中，共鉴定了 12 种转化产物。氟啶酮降解途径由吡咯部分的连续羟化和羰基化以及氧化氰基吡咯环在 NH-C 键处的断裂引发。检测到 2,2-二氟-2H-1,3-苯并二氧杂环-4-羧酸证实了分子的脱氰和脱氨，而其转化为暂定鉴定的化合物 2,3-二羟基苯甲酸表明其脱氟。高通量扩增子测序表明，HRT 缩短导致 α-多样性降低，β-多样性发生显著变化，细菌群落组成从初始的活性污泥系统典型群落转变为由能够进行高级降解和/或好氧反硝化的细菌分类群组成的群落，如梭菌、寡养单胞菌、假单胞菌和 Terrimonas。总的来说，在微需氧条件下运行的固定化细胞生物反应器最大限度地降低了曝气成本，可以为净化受氟啶酮污染的农业工业废水提供可持续的解决方案。
