Sredlova, K., Z. Skrob, A. Filipova, P. Main, J. Holecova, and T. Cajthaml.
Water Research 170:115274(2020)

A cost-effective method for PCB bioremediation that utilizes the degradation capability of Pleurotus ostreatus (the oyster mushroom) was laboratory and pilot tested. Several 1 L lab-scale reactors were optimized. Oyster mushrooms from a commercial farm were used as a fungal inoculum and growth substrate. The highest degradation efficiency (87%) was obtained with a continuous low-flow setup, which was then scaled up to 500 L capacity and used for the treatment of 4000 L of real contaminated groundwater containing 0.1-1 µg/L PCBs. The trickle-bed pilot-scale bioreactor was able to remove 82, 80, 65, and 30-50% of di-, tri-, tetra- and penta-chlorinated PCB congeners, respectively. No degradation was observed for hexa- or hepta-chlorinated congeners. Multiple mono- and dichlorobenzoic acids 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. 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.