title: Detailed investigation of the microbial community in foaming activated sludge reveals novel foam formers.
abstract: Foaming of activated sludge (AS) causes adverse impacts on wastewater treatment operation and hygiene. In this study, we investigated the microbial communities of foam, foaming AS and non-foaming AS in a sewage treatment plant via deep-sequencing of the taxonomic marker genes 16S rRNA and mycobacterial rpoB and a metagenomic approach. In addition to Actinobacteria, many genera (e.g., Clostridium XI, Arcobacter, Flavobacterium) were more abundant in the foam than in the AS. On the other hand, deep-sequencing of rpoB did not detect any obligate pathogenic mycobacteria in the foam. We found that unknown factors other than the abundance of Gordonia sp. could determine the foaming process, because abundance of the same species was stable before and after a foaming event over six months. More interestingly, although the dominant Gordonia foam former was the closest with G. amarae, it was identified as an undescribed Gordonia species by referring to the 16S rRNA gene, gyrB and, most convincingly, the reconstructed draft genome from metagenomic reads. Our results, based on metagenomics and deep sequencing, reveal that foams are derived from diverse taxa, which expands previous understanding and provides new insight into the underlying complications of the foaming phenomenon in AS.
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Guo
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Wang
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Yu
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D033601:Gordonia Bacterium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D059014:High-Throughput Nucleotide Sequencing; D056186:Metagenomics; D009161:Mycobacterium / Q000235:genetics / Q000302:isolation & purification; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D027081:DNA Gyrase