Genus nameAcinetobacter
Alternative namesEikelboom Type 1863 (some)
NCBI taxonomy ID469



16S gene copy number6-7

 In situOther
Hydrophobic cell surface11

Whole-cell identification of Acinetobacter spp. Viewed by epifluorescence microscopy. Bar, 10 microns. In situ hybridization of activated sludge from stage 1 of the Munchen II plant with fluorescein-labeled probe ACA. Filamentous bacteria of Eikelboom type 1863 show bright signals. - Source:3

Aerobic heterotroph
Fatty acids
Proteins/Amino acids

POSNEGVariableNot assessed


They can be common in WWTP, but often due to a high abundance in the incoming wastewater 1. Members of the genus generally possess a strictly aerobic heterotrophic metabolism, though no in situ physiological data is available for members within activated sludge treatment plants. Due to the high number of polyphosphate accumulating isolates they were once thought to be the important PAO in EBPR. Although many of these isolates showed high levels of aerobic polyP and PHA accumulation, none could accumulate substrates like acetate and store them anaerobically as PHA. Anaerobic P release was also much lower than that reported for EBPR biomasses, and was not linked causally to the presence of substrate 4 5 6. Cells are rods or cocci occurring in clusters or chains 3. Sometimes filamentous, possessing the 'Eikelboom Type 1863' morphotype 3 7. Not considered important for bulking but has been shown to be enriched in the surface scum layer suggested to be due to the production of biosurfactants and cell wall properties 8.

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FISH probes

[ACA23A] 3


 In situOther
Aerobic Heterotroph3910
Nitrite Reduction
Sulphate Reduction
Fatty Acids10
Proteins/Amino Acids10

Abundance Information

 10 % percentileMedian90 % percentile
Activated Sludge000

Predominant InInfluent


[1] Saunders, Albertsen, Vollertsen, Nielsen - The activated sludge ecosystem contains a core community of abundant organisms. - ISME J 10(1): 11-20. doi:10.1038/ismej.2015.117

[2] - NCBI genome database, NCBI id 469 -

[3] Wagner, Erhart, Manz, Amann, Lemmer, Wedi, et al. - Development of an rRNA-targeted oligonucleotide probe specific for the genus Acinetobacter and its application for in situ monitoring in activated sludge. - Appl. Environ. Microbiol. 60(3): 792-800.

[4] Tandoi, V., Majone, M., May, J.W., and Ramadori, R. (1998) The behaviour of polyphosphate accumulating Acinetobacter isolates in an anerobic-aerobic chemostat. Water Res 32: 2903-2912. - Tandoi Et Al 1998 -

[5] Jenkins, D., and Tandoi, V. (1991) The applied microbiology of enhanced biological phosphate removal - accomplishments and needs. Water Res 25: 1471-1478. - Jenkins And Tandoi 1991 -

[6] Seviour, Mino, Onuki - The microbiology of biological phosphorus removal in activated sludge systems. - FEMS Microbiol. Rev. 27(1): 99-127.

[7] Seviour, Blackall, Christensson, Hugenholtz, Cunningham, Bradford, et al. - The filamentous morphotype Eikelboom type 1863 is not a single genetic entity. - J. Appl. Microbiol. 82(4): 411-21.

[8] Müller, Schade, Lemmer - Filamentous scum bacteria in activated sludge plants: detection and identification quality by conventional activated sludge microscopy versus fluorescence in situ hybridization. - Water Environ. Res. 79(11): 2274-86.

[9] Lucia Martins Teixeira., and Vania Lucia Carreira Merquior. (2014) The family Moraxellaceae. In: E. Rosenberg., E.F. DeLong., S. Lory., E. Stackebrandt., F. Thompson. The Prokaryotes: Gammaproteobacteria. Pp 443-476. Springer, Berlin, Heidelberg. - Martins Teixeira And Carreira Merquiror 2014 -

[10] Garrity., G.M., Bell, J.A., Lilburn, T. (2005) Pseudomonadales Orla-Jensen 1921 270th. In: D. J. Brenner., N.R. Kreig., J.T. Staley., G.M., Garrity., D.R., Boone., P. DeVos., M. Goodfellow., F.R. Rainey., K-H. Schleifer. Bergeys Manual of systemmatic bacteriology. Vol 2: The proteobacteria Part B The Gammaproteobacteria. pp 425-437. Springer, U.S. - Garrity Et Al 2005 -

[11] Rosenberg, M., Gutnick, D., and Rosenberg, E. (1980) Adherance of bacteria to hydrocarbons: a simple method for measuring cell-suface hydrophobicity. FEMS Microbiology letters. 9. 29-33. - Rosenberg Et Al 1980 -

[12] Bond, Erhart, Wagner, Keller, Blackall - Identification of some of the major groups of bacteria in efficient and nonefficient biological phosphorus removal activated sludge systems. - Appl. Environ. Microbiol. 65(9): 4077-84.

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The online MiDAS field guide is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.


The MiDAS taxonomy is a manual curation of the Silva database and is redistributed for non-commercial use only.


Citing MiDAS: McIlroy S.J., Saunders A.M., Albertsen M., Nierychlo M., McIlroy B., Hansen A.A., Karst S.M., Nielsen J.L., Nielsen P.H. (2015) MiDAS: the field guide to the microbes of activated sludge. Database, Vol. 2015

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