Metagenomic insight into the bioaugmentation mechanism of Phanerochaete chrysosporium in an activated sludge system treating coking wastewater

Phanerochaete chrysosporium was seeded to a sequencing batch reactor treating phenol wastewater. Compared to the contrast reactor (R1), the bioaugmented reactor (R2) exhibits better performance in sludge settling ability, as well as biomass and phenol removal, even though the added fungus is not persistently surviving in the reactor. Bioaugmentation improved bacterial population, growing up to 10,000 times higher than that of eukaryotes. Metagenomic sequencing results show the bioaugmentation finally increases bacterial and eukaryotic richness, but reduces their community diversity. In contrast to R1, bacterial distribution in R2 is more concentrated in Proteobacteria. The relative abundances of filamentous fungi, yeast and microalgae in R2 are all higher than those in R1 at different treatment phases, and two reactors are finally dominated by different protozoan and metazoan. In conclusion, P. chrysosporium improves reactor performances by influencing microbial community structure, and this phenomenon might be attributed to the ecological competition in sludge and toxicity reduction of phenol wastewater. The novelty of this study emphasizes why a species which is not persistently active in bioreactor still plays a crucial role in enhancing reactor performance. Results obtained here impact the conventional criteria for selection of bioaugmentation microbes used in activated sludge systems. (C) 2016 Elsevier B.V. All rights reserved.