Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, 12801, Prague 2, Czech Republic; Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.
DEKONTA a.s, Volutová 2523, 15800, Prague 5, Czech Republic.
Water Res. 2020 Mar 1;170:115274. doi: 10.1016/j.watres.2019.115274. Epub 2019 Nov 5.
Due to their persistence, polychlorinated biphenyls (PCBs) represent a group of important environmental pollutants, but conventional physicochemical decontamination techniques for their removal are usually expensive. The main aim of this work was to develop a cost-effective method for PCB bioremediation, focusing on contaminated water and utilizing the well-known degradation capability of Pleurotus ostreatus (the oyster mushroom). For this purpose, the conditions of several laboratory-scale reactors (working volume 1 L) were optimized. Spent oyster mushroom substrate obtained from a commercial farm was used as a fungal inoculum and growth substrate. The highest degradation efficiency (87%) was recorded with a continuous low-flow setup, which was subsequently scaled up (working volume 500 L) and used for the treatment of 4000 L of real contaminated groundwater containing 0.1-1 μg/L of PCBs. This trickle-bed pilot-scale bioreactor was able to remove 82, 80, 65, and 30-50% of di-, tri-, tetra- and pentachlorinated PCB congeners, respectively. No degradation was observed for hexa- or heptachlorinated congeners. Multiple mono- and dichlorobenzoic acids (CBAs) were identified as transformation products by mass spectrometry, confirming the role of biodegradation in PCB removal. A Vibrio fischeri bioluminescence inhibition test revealed slight ecotoxicity of the primary reactor effluent (sampling after 24 h), which was quickly suppressed once the effluent passed through the reactor for the second time. Moreover, no other effluent exhibited toxicity for the rest of the experiment (71 days in total). Microbial analyses (phospholipid fatty acid analysis and next-generation sequencing) showed that P. ostreatus was able to degrade PCBs in the presence of an abundance of other fungal species as well as aerobic and anaerobic bacteria. Overall, this study proved the suitability of the use of spent oyster mushroom substrate in a bioremediation practice, even for pollutants as recalcitrant as PCBs.
由于其持久性，多氯联苯（PCBs）是一组重要的环境污染物，但传统的理化去污技术通常成本高昂。这项工作的主要目的是开发一种经济有效的 PCB 生物修复方法，重点是受污染的水，并利用众所周知的糙皮侧耳（牡蛎蘑菇）的降解能力。为此，优化了几个实验室规模的反应器（工作体积 1 L）的条件。从商业农场获得的废弃牡蛎蘑菇基质被用作真菌接种物和生长基质。在连续低流量设置下，记录到最高的降解效率（87%），随后将其放大（工作体积 500 L），并用于处理含有 0.1-1 μg/L PCB 的 4000 L 实际受污染地下水。这个滴流床中试生物反应器能够去除 82%、80%、65%和 30-50%的二氯、三氯、四氯和五氯 PCB 同系物，分别。未观察到六氯或七氯同系物的降解。通过质谱鉴定出多种单氯和二氯苯甲酸（CBAs）作为转化产物，证实了生物降解在 PCB 去除中的作用。发光细菌 Vibrio fischeri 生物发光抑制试验表明，初级反应器流出物（24 小时后采样）具有轻微的生态毒性，但一旦流出物第二次通过反应器，毒性很快就会被抑制。此外，在实验的其余时间（总共 71 天），没有其他流出物表现出毒性。微生物分析（磷脂脂肪酸分析和下一代测序）表明，糙皮侧耳能够在其他真菌以及好氧和厌氧细菌大量存在的情况下降解 PCBs。总的来说，这项研究证明了使用废弃的牡蛎蘑菇基质在生物修复实践中的适用性，即使是对 PCBs 等难降解污染物也是如此。
