Release of Extracellular Polymeric Substance and Disintegration of Anaerobic Granular Sludge under  Reduced Sulfur Compounds-Rich Conditions

Kobayashi, Takuro; Xu, Kai; Chiku, Haruyuki

doi:10.3390/en8087968

Cited by 36 publications

(8 citation statements)

References 46 publications

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“…Fewer studies, however, have addressed the ultimate fate of granular biofilms. Moreover, several studies have reported the spontaneous disintegration of granular biofilms, ultimately leading to process failure (McHugh et al, 2006;Baloch et al, 2008;Kobayashi et al, 2015). Studies into development and fate of granules could help prevent or mitigate such phenomena.…”

Section: Introductionmentioning

confidence: 99%

Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development

et al. 2020

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Methanogenic sludge granules are densely packed, small, spherical biofilms found in anaerobic digesters used to treat industrial wastewaters, where they underpin efficient organic waste conversion and biogas production. Each granule theoretically houses representative microorganisms from all of the trophic groups implicated in the successive and interdependent reactions of the anaerobic digestion (AD) process. Information on exactly how methanogenic granules develop, and their eventual fate will be important for precision management of environmental biotechnologies. Granules from a full-scale bioreactor were size-separated into small (0.6-1 mm), medium (1-1.4 mm), and large (1.4-1.8 mm) size fractions. Twelve laboratory-scale bioreactors were operated using either small, medium, or large granules, or unfractionated sludge. After >50 days of operation, the granule size distribution in each of the small, medium, and large bioreactor sets had diversified beyond-to both bigger and smaller than-the size fraction used for inoculation. Interestingly, extra-small (XS; <0.6 mm) granules were observed, and retained in all of the bioreactors, suggesting the continuous nature of granulation, and/or the breakage of larger granules into XS bits. Moreover, evidence suggested that even granules with small diameters could break. "New" granules from each emerging size were analyzed by studying community structure based on high-throughput 16S rRNA gene sequencing. Methanobacterium, Aminobacterium, Propionibacteriaceae, and Desulfovibrio represented the majority of the community in new granules. H2-using, and not acetoclastic, methanogens appeared more important, and were associated with abundant syntrophic bacteria. Multivariate integration (MINT) analyses identified distinct discriminant taxa responsible for shaping the microbial communities in different-sized granules.

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Section: Introductionmentioning

confidence: 99%

Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development

et al. 2020

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“…1 ). The most widely accepted theory states that granulation starts with a formation of a future granule’s core, comprised of filamentous methanogenic bacteria Methanothrix , together with Methanosarcina , which secrete extracellular polymers (ECP) [ 5 – 7 ]. The surface charge of this core changes and become attractive for the oppositely charged anaerobic bacteria that are present in the dispersed inoculum of a UASB rector [ 8 – 10 ].…”

Section: Introductionmentioning

confidence: 99%

Modeling de novo granulation of anaerobic sludge

et al. 2017

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BackgroundA unique combination of mechanical, physiochemical and biological forces influences granulation during processes of anaerobic digestion. Understanding this process requires a systems biology approach due to the need to consider not just single-cell metabolic processes, but also the multicellular organization and development of the granule.ResultsIn this computational experiment, we address the role that physiochemical and biological processes play in granulation and provide a literature-validated working model of anaerobic granule de novo formation. The agent-based model developed in a cDynoMiCs simulation environment successfully demonstrated a de novo granulation in a glucose fed system, with the average specific methanogenic activity of 1.11 ml C H 4/g biomass and formation of a 0.5 mm mature granule in 33 days. The simulated granules exhibit experimental observations of radial stratification: a central dead core surrounded by methanogens then encased in acidogens. Practical application of the granulation model was assessed on the anaerobic digestion of low-strength wastewater by measuring the changes in methane yield as experimental configuration parameters were systematically searched.ConclusionsIn the model, the emergence of multicellular organization of anaerobic granules from randomly mixed population of methanogens and acidogens was observed and validated. The model of anaerobic de novo granulation can be used to predict the morphology of the anaerobic granules in a alternative substrates of interest and to estimate methane potential of the resulting microbial consortia. The study demonstrates a successful integration of a systems biology approach to model multicellular systems with the engineering of an efficient anaerobic digestion system.

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“…Thus, the observed increase in their removal could be attributed to the enhanced hydrophobic interaction between these two compounds and sludge with SO4 2increase in the influent. Indeed, as discussed above, it has been reported that high SO4 2concentration could increase the release of EPS and thus enhance the hydrophobicity of anaerobic sludge (Kobayashi et al, 2015). Most hydrophilic TrOCs belong to the third group, which showed an initial decrease and then increase in the removal by AnMBR with continuous increase in the influent SO4 2concentration.…”

Section: Membrane Foulingmentioning

confidence: 75%

“…On the other hand, the residual concentrations of carazolol, amitriptyline, and hydroxyzine in the sludge phase increased with SO4 2addition. This result could be attributed to the change of biomass characteristics, for example, surface charge and hydrophobicity, caused by an enhanced release of EPS with sulphur addition (Kobayashi et al, 2015).…”

Section: Troc Adsorption On Sludgementioning

confidence: 99%

Effects of sulphur on the performance of an anaerobic membrane bioreactor: Biological stability, trace organic contaminant removal, and membrane fouling

Song

Luo

McDonald

et al. 2018

Bioresource Technology

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This study investigated the impact of sulphur content on the performance of an anaerobic membrane bioreactor (AnMBR) with an emphasis on the biological stability, contaminant removal, and membrane fouling. Removal of 38 trace organic contaminants (TrOCs) that are ubiquitously present in municipal wastewater by AnMBR was evaluated. Results show that basic biological performance of AnMBR regarding biomass growth and the removal of chemical oxygen demand (COD) was not affected by sulphur addition when the influent COD/SO ratio was maintained higher than 10. Nevertheless, the content of hydrogen sulphate in the produced biogas increased significantly and membrane fouling was exacerbated with sulphur addition. Moreover, the increase in sulphur content considerably affected the removal of some hydrophilic TrOCs and their residuals in the sludge phase during AnMBR operation. By contrast, no significant impact on the removal of hydrophobic TrOCs was noted with sulphur addition to AnMBR.

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Release of Extracellular Polymeric Substance and Disintegration of Anaerobic Granular Sludge under Reduced Sulfur Compounds-Rich Conditions

Cited by 36 publications

References 46 publications

Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development

Growth and Break-Up of Methanogenic Granules Suggests Mechanisms for Biofilm and Community Development

Modeling de novo granulation of anaerobic sludge

Effects of sulphur on the performance of an anaerobic membrane bioreactor: Biological stability, trace organic contaminant removal, and membrane fouling

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