Publication Details

Category Text Publication
Reference Category Journals
DOI 10.3389/fmicb.2013.00175
Title (Primary) Assessment of bacterial and structural dynamics in aerobic granular biofilms
Author Weissbrodt, D.G.; Neu, T.R.; Kuhlicke, U.; Rappaz, Y.; Holliger, C.
Source Titel Frontiers in Microbiology
Year 2013
Department FLOEK
Volume 4
Page From art. 175
Language englisch
Keywords biological wastewater treatment, aerobic granular sludge, granular biofilm formation and structure, T-RFLP, pyrosequencing, CLSM, FISH, FLBA
UFZ wide themes RU2;
Abstract Aerobic granular sludge (AGS) is based on self-granulated flocs forming mobile biofilms with a gel-like consistence. Bacterial and structural dynamics from flocs to granules were followed in anaerobic-aerobic sequencing batch reactors (SBR) fed with synthetic wastewater, namely a bubble column (BC-SBR) operated under wash-out conditions for fast granulation, and two stirred-tank enrichments of Accumulibacter (PAO-SBR) and Competibacter (GAO-SBR) operated at steady-state. In the BC-SBR, granules formed within 2 weeks by swelling of Zoogloea colonies around flocs, developing subsequently smooth zoogloeal biofilms. However, Zoogloea predominance (37–79%) led to deteriorated nutrient removal during the first months of reactor operation. Upon maturation, improved nitrification (80–100%), nitrogen removal (43–83%), and high but unstable dephosphatation (75–100%) were obtained. Proliferation of dense clusters of nitrifiers, Accumulibacter, and Competibacter from granule cores outwards resulted in heterogeneous bioaggregates, inside which only low abundance Zoogloea (<5%) were detected in biofilm interstices. The presence of different extracellular glycoconjugates detected by fluorescence lectin-binding analysis showed the complex nature of the intracellular matrix of these granules. In the PAO-SBR, granulation occurred within two months with abundant and active Accumulibacter populations (56 ± 10%) that were selected under full anaerobic uptake of volatile fatty acids and that aggregated as dense clusters within heterogeneous granules. Flocs self-granulated in the GAO-SBR after 480 days during a period of over-aeration caused by biofilm growth on the oxygen sensor. Granules were dominated by heterogeneous clusters of Competibacter (37 ± 11%). Zoogloea were never abundant in biomass of both PAO- and GAO-SBRs. This study showed that Zoogloea, Accumulibacter, and Competibacter affiliates can form granules, and that the granulation mechanisms rely on the dominant population involved.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=13972
Weissbrodt, D.G., Neu, T.R., Kuhlicke, U., Rappaz, Y., Holliger, C. (2013):
Assessment of bacterial and structural dynamics in aerobic granular biofilms
Front. Microbiol. 4 , art. 175 10.3389/fmicb.2013.00175