title: The ratio of metabolically active versus total Mycolata populations triggers foaming in a membrane bioreactor.
abstract: The abundance of total and metabolically active populations of Mycolata was evaluated in a full-scale membrane bioreactor (MBR) experiencing seasonal foaming, using quantitative PCR (qPCR) and retrotranscribed qPCR (RT-qPCR) targeting the 16S rRNA gene sequence. While the abundance of total Mycolata remained stable (10(10) copies of 16S rRNA genes/L activated sludge) throughout four different experimental phases, significant variations (up to one order of magnitude) were observed when the 16S rRNA was targeted. The highest ratios of metabolically active versus total Mycolata populations were observed in samples of two experimental phases when foaming was experienced in the MBR. Non-metric multidimensional scaling and BIO-ENV analyses demonstrated that this ratio was positively correlated to the concentrations of substrates in the influent water, F/M ratio, and pH, and negatively correlated to temperature and solids retention time. It the first time that the ratio of metabolically active versus total Mycolata is found to be a key parameter triggering foaming in the MBR; thus, we propose it as a candidate predictive tool.
authors: Department of Microbiology and Institute of Water Research, University of Granada, Granada, Spain. Electronic address: paulamaza@ugr.es.
authors: P
authors: P
authors: Maza-Márquez
authors: Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium.
authors: R
authors: R
authors: Vílchez-Vargas
authors: Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000 Gent, Belgium.
authors: N
authors: N
authors: Boon
authors: Department of Microbiology and Institute of Water Research, University of Granada, Granada, Spain.
authors: J
authors: J
authors: González-López
authors: Department of Microbiology and Institute of Water Research, University of Granada, Granada, Spain.
authors: M V
authors: MV
authors: Martínez-Toledo
authors: Department of Microbiology and Institute of Water Research, University of Granada, Granada, Spain.
authors: B
authors: B
authors: Rodelas
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D008567:Membranes, Artificial; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D008567:Membranes, Artificial; D012336:RNA, Ribosomal, 16S
keywords: Foaming; Membrane bioreactor (MBR); Mycolata; Non-metric multidimensional scaling (MDS); RT-qPCR; qPCR