Labeling enzymes and extracellular polymeric substances in aerobic granules

Lee, Chun-Chi; Lee, Dong Hoon; Lai, Juin‐Yih

doi:10.1016/j.jtice.2009.04.002

“…This might be sustained by detachment phenomena and the access of substrates to central granule zones. Similarly to planar biofilms and to what has also been observed by different authors (Lemaire et al, 2008a; Lee et al, 2009; Barr et al, 2010), granules exhibit more complex structures than stratified architectures considered in conceptual and mathematical models. Granules heterogeneities can also explain the differences in the spatial organization of target organisms in the granular biofilm ecosystems depending on the process operation.…”

Section: Discussionsupporting

confidence: 66%

Assessment of bacterial and structural dynamics in aerobic granular biofilms

Weissbrodt¹,

Neu²,

Kuhlicke³

et al. 2013

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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.

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“…This might be sustained by detachment phenomena and the access of substrates to central granule zones. Similarly to planar biofilms and to what has also been observed by different authors (Lemaire et al, 2008a;Lee et al, 2009;Barr et al, 2010), granules exhibit more complex structures than stratified architectures considered in conceptual and mathematical models. Granules heterogeneities can also explain the differences in the spatial organization of target organisms in the granular biofilm ecosystems depending on the process operation.…”

Section: Figure 8 | Evolutions Of the Richness And Shannon's H' Diversupporting

confidence: 61%

- Taxonomic Precision of Different Hypervariable Regions of 16S rRNA Gene and Annotation Methods for Functional Bacterial Groups in Biological Wastewater Treatment

2016

Bioremediation of Wastewater

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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.Keywords: biological wastewater treatment, aerobic granular sludge, granular biofilm formation and structure, T-RFLP, pyrosequencing, CLSM, FISH, FLBA INTRODUCTIONConventional activated sludge systems operated for biological nutrient removal (BNR) from wastewater require a high footprint for the integration of activated sludge tanks enabling microbial processes and of secondary clarifiers for the separation of biomass from the treated effluent. The aerobic granular sludge (AGS) process has recently deserved the attention of innovation analysts (Radauer et al., 2012). This technology has been developed for intensified BNR and secondary clarification in single sequencing batch reactors (SBR), and is related to definite savings in land area, construction, and operation costs according to reports on the performance of first full-scale plants (Giesen et al., 2012;Inocencio et al., 2013). AGS comprises suspended biofilm particles, called aerobic granules, formed by self-aggregation of microbial populations (Morgenroth et al., 1997). Although some full...

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“…Owing to the binding specificity and the different emittance spectra of the dyes, multicolor fluorescent microscopy enables the simultaneous visualization of more individual components of the sludge flocs. Biopolymers and bacteria can be stained using specific fluorescent dyes, while a recent study proposes the staining of extracellular enzymes with immunohystochemical methods used in clinical diagnosis . In practice the number of simultaneously revealed components is limited because of the specificity and the spectral peak interferences of the dyes used, the lack of precise technology and other practical limitations.…”

Section: Introductionmentioning

confidence: 99%

In situ imaging of biopolymers and extracellular enzymes in activated sludge flocs of a municipal wastewater treatment plant

Szilveszter

¹

,

Ráduly

²

,

Ábrahám

³

et al. 2012

J of Chemical Tech & Biotech

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BACKGROUND: The aim of this study was to investigate biopolymers and extracellular enzymes in whole activated sludge flocs originating from a full-scale wastewater treatment plant, by means of confocal laser scanning microscopy (CLSM) techniques. Both sectioned and whole activated sludge floc samples have been stained using specific fluorochromes and immunostains in order to visualize the structural and functional characteristics of these bioaggregates. Samples were stained for visualization of lipids, sugars, total cells, esterase enzyme producing bacteria, and for β-glycosidase (EC3.2.1.21), alkaline phosphatase (EC3.1.3.1) and trypsin (EC3.4.21.4) enzymes. Simultaneous staining schemes were applied and immunostaining specificity tests were performed. RESULTS: By the CLSM imaging and the 3-D reconstruction of the stained flocs the distributions of the targeted floc componentswere successfully assessed. The immunostain specificity controls gave satisfactory results in each case. The reflected total cells-to-enzymes ratio was repeatedly higher for the sectioned samples. CONCLUSIONS:The CLSM imaging of whole sludge flocs delivers valuable information on the spatial distribution of the floc build-up materials, with a satisfactory visualization accuracy of the individual components. The images of whole and sectioned samples showed similar distributions of the floc components, but the consistent differences revealed in cells-to-enzymes ratios call for further research.

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Labeling enzymes and extracellular polymeric substances in aerobic granules

Cited by 11 publications

References 25 publications

Assessment of bacterial and structural dynamics in aerobic granular biofilms

Assessment of bacterial and structural dynamics in aerobic granular biofilms

- Taxonomic Precision of Different Hypervariable Regions of 16S rRNA Gene and Annotation Methods for Functional Bacterial Groups in Biological Wastewater Treatment

In situ imaging of biopolymers and extracellular enzymes in activated sludge flocs of a municipal wastewater treatment plant

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