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The filamentous morphotype Eikelboom type 1863 is not a single genetic entity
E M Seviour1, L L Blackall, C Christensson
1Biotechnology Research Centre, La Trobe University, Bendigo, Victoria, Australia.
Journal of Applied Microbiology
|April 1, 1997
Summary
Microscopic identification of filamentous bacteria in activated sludge can be misleading. Genetic analysis revealed isolates with Eikelboom Type 1863 morphology belonged to diverse bacterial genera, including Chryseobacterium, Acinetobacter, and Moraxella.
Area of Science:
- Environmental microbiology
- Wastewater treatment microbiology
- Bacterial taxonomy
Background:
- Filamentous bacteria are crucial for activated sludge floc formation and settling.
- Microscopic identification, such as Eikelboom Type 1863, is commonly used for filamentous bacteria in wastewater treatment.
- The accuracy of microscopic identification for diverse bacterial morphotypes is not fully understood.
Purpose of the Study:
- To investigate the taxonomic diversity of filamentous bacteria exhibiting Eikelboom Type 1863 morphology.
- To assess the reliability of microscopic identification for filamentous bacteria in activated sludge.
Main Methods:
- Isolation of filamentous bacteria from activated sludge.
- Phenotypic characterization of isolates.
- 16S ribosomal DNA (rDNA) sequencing for phylogenetic analysis.
Main Results:
- Five isolates with Eikelboom Type 1863 morphology were obtained.
- Phylogenetic analysis revealed the isolates were polyphyletic.
- Isolates belonged to distinct genera: Chryseobacterium (2 isolates), Acinetobacter (2 isolates), and Moraxella (1 isolate).
Conclusions:
- Microscopic identification alone is insufficient for accurate identification of filamentous bacteria in activated sludge.
- Eikelboom Type 1863 represents a morphotype shared by phylogenetically diverse bacteria.
- Findings highlight the importance of integrating molecular methods with microscopy for reliable bacterial identification in environmental samples.