Phylogenetic analysis and in situ identification of "Nostocoida limicola"-like filamentous bacteria in activated sludge from industrial wastewater treatment plants.

The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened activated sludge samples from different industries with sometimes severe bulking sludge problems. A special focus was paid to filaments which resembled "Nostocoida limicola", a filamentous bacterium which was found to be present in many WWTPs. These filamentous bacteria are hardly cultivable and only one strain was obtained and maintained in co-culture with a yeast. The 16S rRNA sequences of several other "Nostocoida limicola"-like filamentous bacteria from different sludge samples were obtained by micromanipulation and different molecular-biological methods. The sequences were phylogenetically analyzed and specific molecular probes were developed and applied. The results clearly demonstrate that "Nostocoida limicola"-like filaments from industrial WWTPs are different from all other "Nostocoida limicola" types investigated so far. Our strains are affiliated to the alpha-subclass of Proteobacteria.

Snaidr I ，Beimfohr C ，Levantesi C ，Rossetti S ，van der Waarde J ，Geurkink B ，Elkelboom D ，Lemaitre M ，Tandoi V ... -  《WATER SCIENCE AND TECHNOLOGY》

Phylogenetic and physiological characterization of a "Nostocoida limicola"-like organism isolated from activated sludge.

Ten strains of "Nostocoida limicola"-like organisms were isolated from a municipal wastewater treatment plant with minor industrial effluent. The near complete 16S rDNA sequences were determined for four strains to analyze the position of the organisms within the phylogenetic tree. All four isolates showed the same 16S rRNA sequence and cluster within the green non sulfur bacteria. Hybridization with oligonucleotide probe AHW183 designed complementarily to diagnostic regions of the 16S rRNA sequences showed a positive reaction with all isolated strains. Hybridization of activated sludge samples with probe AHW183 indicates the filamentous "Nostocoida limicola"-like bacteria commonly to occur inside the sludge flocs and to hardly be detected within the flocs without a specific staining. On HA-medium all strains grow as long coiled, unbranched and unsheathed filaments which usually stain gram positive and show a variable Neisser reaction. The isolates grow well in liquid HA-medium at COD values between 1 to 4 g O2 h(-1) and a pH range from 6.0-7.8. No growth is detected in liquid R2A-medium and several synthetic mineral salts media containing various carbon and nitrogen sources.

Schade M ，Beimfohr C ，Lemmer H 《WATER SCIENCE AND TECHNOLOGY》

Molecular monitoring of bulking sludge in industrial wastewater treatment plants.

Fluorescent In Situ Hybridisation (FISH) was used to monitor the presence of filamentous microorganisms in industrial wastewater treatment plants (WWTPs). Monitoring with a restricted set of FISH probes in WWTPs from potato industry showed growth and decline of Thiothrix populations that could be linked to operational procedures. In a follow up project new FISH probes were developed for filamentous bacteria in industrial WWTPs and 70 WWTPs were analysed for presence of these filaments. Several newly described species of filamentous bacteria appear to be common and dominant in industrial WWTPs. Monitoring of a WWTP from textile industry showed growth and decline of one of these organisms when operational conditions in the plant were varied. The present paper demonstrates that bulking sludge in industrial wastewater treatment plants can effectively be monitored using a combination of standard chemical analyses and the FISH technique.

van der Waarde J ，Krooneman J ，Geurkink B ，van der Werf A ，Eikelboom D ，Beimfohr C ，Snaidr J ，Levantesi C ，Tandoi V ... -  《WATER SCIENCE AND TECHNOLOGY》

The "Nostocoida limicola" story: resolving the phylogeny of this morphotype responsible for bulking in activated sludge.

On the basis of 16S rRNA sequence analyses of several isolates of "Nostocoida limicola" from activated sludge plants in Australia and other countries, it is clear that "N. limicola" I, II and III are not three morphological variants of a single bacterium but at least three phylogenetically different bacteria. Data show that "N. limicola" I are members of at least two genera in the low mol% G+C gram-positive bacteria, while some isolates of "N. limicola" II belong to the high mol% G+C gram positive bacteria, and "N. limicola" III is a member of the Planctomycetales. Design and application of 16S rRNA targeted probes for each to biomass samples suggests that their phylogeny is more diverse than pure culture studies would suggest.

Seviour RJ ，Liu JR ，Seviour EM ，McKenzie CA ，Blackall LL ，Saint CP ... -  《WATER SCIENCE AND TECHNOLOGY》

Multiple approaches to assess filamentous bacterial growth in activated sludge under different carbon source conditions.

To compare molecular and microscopic approaches in determining which filamentous bacteria grow in activated sludge reactors when different carbon sources and different activated sludge mixed liquor inocula are used. Microscopic and molecular (Denaturing Gradient Gel Electrophoresis and Fluorescent In Situ Hybridization) techniques were used to determine which filamentous bacteria became dominant in lab scale reactors treating wastewater composed of different carbon sources. Molecular analysis indicated the presence of Sphaerotilus natans and Thiothrix-related organisms. Microscopy indicated the presence of Nostocoida limicola in some reactors. Sludge volume index increased as filament abundance increased. The detection level of DGGE analysis increased when the abundance levels of the filaments were high. Simultaneous application of traditional and molecular methods was effective, and highlighted the advantages and limitations of each method. Readily biodegradable substances favoured the growth of specific filaments in a mixed liquor environment. The origin of inoculum influenced which specific filamentous bacteria grew. The study shows the potential problems when using particular techniques, and highlights the need for multiple approaches when studying filaments. The study also provides more information on which filaments will grow under different carbon source conditions for a given inoculum.

Gulez G ，de Los Reyes FL 3rd 《-》