title: Ecophysiology of mycolic acid-containing Actinobacteria (Mycolata) in activated sludge foams.
abstract: Increasing incidences of activated sludge foaming have been reported in the last decade in Danish plants treating both municipal and industrial wastewaters. In most cases, foaming is caused by the presence of Actinobacteria; branched mycolic acid-containing filaments (the Mycolata) and the unbranched Candidatus'Microthix parvicella'. Surveys from wastewater treatment plants revealed that the Mycolata were the dominant filamentous bacteria in the foam. Gordonia amarae-like organisms and those with the morphology of Skermania piniformis were frequently observed, and they often coexisted. Their identity was confirmed by FISH, using a new permeabilization procedure. It was not possible to identify all abundant Mycolata using existing FISH probes, which suggests the presence of currently undetectable and potentially undescribed populations. Furthermore, some Mycolata failed to give any FISH signal, although substrate uptake experiments with microautoradiography revealed that they were physiologically active. Ecophysiological studies were performed on the Mycolata identified by their morphology or FISH in both foams and mixed liquors. Large differences were seen among the Mycolata in levels of substrate assimilation and substrate uptake abilities in the presence of different electron acceptors. These differences were ascribed mainly to the presence of currently undescribed Mycolata species and/or differences in foam age.
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Sohngaardsholmsvej, Aalborg, Denmark.
authors.forename: Caroline
authors.initials: C
authors.lastname: Kragelund
authors.forename: Zaneta
authors.initials: Z
authors.lastname: Remesova
authors.forename: Jeppe Lund
authors.initials: JL
authors.lastname: Nielsen
authors.forename: Trine Rolighed
authors.initials: TR
authors.lastname: Thomsen
authors.forename: Kathryn
authors.initials: K
authors.lastname: Eales
authors.forename: Robert
authors.initials: R
authors.lastname: Seviour
authors.forename: Jiri
authors.initials: J
authors.lastname: Wanner
authors.forename: Per Halkjaer
authors.initials: PH
authors.lastname: Nielsen
mesh_terms: D000192:Actinomycetales / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D000332:Aerobiosis / Q000502:physiology; D000693:Anaerobiosis / Q000502:physiology; D001345:Autoradiography; D049109:Cell Proliferation; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008853:Microscopy; D009171:Mycolic Acids / Q000032:analysis*; D010539:Permeability; D011108:Polymers / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*
chemical_list: D009171:Mycolic Acids; D011108:Polymers; D012722:Sewage