Bioremediation of long-term PCB-contaminated soil by white-rot fungi

Abstract

The objective of this work was to test the PCB-degrading abilities of two white-rot fungi, namely Pleu-rotus ostreatus and Irpex lacteus, in real contaminated soils with different chemical properties andautochthonous microflora. In addition to the efficiency in PCB removal, attention was given to otherimportant parameters, such as changes in the toxicity and formation of PCB transformation products.Moreover, structural shifts and dynamics of both bacterial and fungal communities were monitoredusing next-generation sequencing and phospholipid fatty acid analysis. The best results were obtainedwith P. ostreatus, which resulted in PCB removals of 18.5, 41.3 and 50.5% from the bulk, top (surface) andrhizosphere, respectively, of dumpsite soils after 12 weeks of treatment. Numerous transformation prod-ucts were detected (hydoxylated and methoxylated PCBs, chlorobenzoates and chlorobenzyl alcohols),which indicates that both fungi were able to oxidize and decompose the aromatic moiety of PCBs in thesoils. Microbial community analysis revealed that P. ostreatus efficiently colonized the soil samples and suppressed other fungal genera. However, the same fungus substantially stimulated bacterial taxa that encompass putative PCB degraders. The results of this study finally demonstrated the feasibility of usingthis fungus for possible scaled-up bioremediation applications.