Distribution of extracellular polymeric substances in aerobic granules

Chen, M. Y.; Lee, D. J.; Tay, Joo‐Hwa

doi:10.1007/s00253-006-0617-x

Cited by 205 publications

(81 citation statements)

References 25 publications

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“…The second port was connected to a PBS solution, and the third port was connected to a mixture of several EPS stains dissolved in PBS. These EPS stains included 5 μM of the green fluorescent nucleic acid stain SYTO 9 (Molecular Probes) (55,56), 20 μg/mL fluorescein isothiocyanate (FITC)-conjugated Concanavalin A (ConA), and 20 μg/mL FITC-conjugated wheat germ agglutinin (WGA). The lectin ConA (Sigma) binds to α-D-mannose, α-Dglucose, and likely alginate (56), whereas the lectin WGA (Sigma) binds to N-acetyl-D-glucosamine and N-acetylneuraminic acid (56).…”

Section: Methodsmentioning

confidence: 99%

Biofilm streamers cause catastrophic disruption of flow with consequences for environmental and medical systems

Drescher

Shen

Bassler

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

314

396

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Biofilms are antibiotic-resistant, sessile bacterial communities that occupy most moist surfaces on Earth and cause chronic and medical device-associated infections. Despite their importance, basic information about biofilm dynamics in common ecological environments is lacking. Here, we demonstrate that flow through soil-like porous materials, industrial filters, and medical stents dramatically modifies the morphology of Pseudomonas aeruginosa biofilms to form 3D streamers, which, over time, bridge the spaces between obstacles and corners in nonuniform environments. We discovered that accumulation of surface-attached biofilm has little effect on flow through such environments, whereas biofilm streamers cause sudden and rapid clogging. We demonstrate that flow-induced shedding of extracellular matrix from surface-attached biofilms generates a sievelike network that captures cells and other biomass, which add to the existing network, causing exponentially fast clogging independent of growth. These results suggest that biofilm streamers are ubiquitous in nature and strongly affect flow through porous materials in environmental, industrial, and medical systems.bioclogging | biofouling | porous media I n the laboratory, bacteria are usually grown as planktonic cells in shaken suspensions, which differs dramatically from the natural environments of most microbes. In their natural habitats, bacteria often live in biofilms (1-3), which are tightly packed, surface-associated assemblies of bacteria that are bound together by extracellular polymeric substances (4, 5). Although biofilms are desirable in waste-water treatment (6), biofilms primarily cause undesirable effects such as chronic infections or clogging of industrial flow systems (1-3). Cells in biofilms display many behavioral differences from planktonic cells, such as a 1,000-fold increase in tolerance to antibiotics (7,8), an altered transcriptome (9-11), and spatially heterogeneous metabolic activity (12, 13). Some of these physiological peculiarities of biofilm-dwelling cells may be due to strong gradients of nutrients and metabolites, which also affect biofilm morphology and composition (14, 15). However, little is known about how physical aspects of the environment affect biofilm dynamics.The opportunistic pathogen Pseudomonas aeruginosa has become a model organism for biofilm studies largely because it forms biofilms in diverse habitats, including soil, rivers, sewage, and medical devices in humans (1, 2, 16). Two features are common to all of these environments: First, the presence of rough surfaces, which at the microscopic level reduce to surfaces with many corners, and second, a pressure-driven flow. The standard assay for growing biofilms in the laboratory abstracts from these realistic environments by typically using a smooth surface as a substrate, and either no flow or a pump to force nutritious medium across the biofilm at a constant flow rate (17-19). These standard assays have enabled the identification of several genes involved in biofilm develo...

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Section: Methodsmentioning

confidence: 99%

Biofilm streamers cause catastrophic disruption of flow with consequences for environmental and medical systems

Drescher

Shen

Bassler

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

314

396

View full text Add to dashboard Cite

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“…Proteins were labeled with fluorescein isothiocyanate (FITC), cellulose was labeled with calcofluor white (CW), and starch was labeled with Con A (Chen, Lee, & Tay, 2007;Adav et al, 2010;Wang, Shen, Yu, Ran, & Xu, 2012). First, 0.1 M sodium bicarbonate buffer was added to the FSBM sample to keep the amine group in a non-protonated form, after which 10 g/L of the FITC solution was added to the sample for 1 h at room temperature.…”

Section: Sbm Fermentationmentioning

confidence: 99%

Effect of soybean meal fermented with Bacillus subtilis BS12 on growth performance and small intestinal immune status of piglets

Zhang

Shi

Wang

et al. 2017

Food and Agricultural Immunology

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This study was aimed to screen a high-efficient strain for degrading antigenic protein in soybean meal (SBM) and evaluate the effect of fermented soybean meal (FSBM) on growth performance of piglets. A Bacillus subtilis strain BS12 was selected through plate and fermentation experiment, which reduced 92.36% less glycinin and 88.44% less β-conglycinin in SBM. A total of 192 piglets were assigned to receive either a diet of SBM with antibiotics (the control group) or a diet containing 10% FSBM without antibiotics. The average daily gain and feed intake of pigs fed FSBM were superior (p < .10) to those fed the control diet. Reduced (p < .05) mRNA expression of pro-inflammatory cytokines was detected in the jejunum and ileum of pigs fed FSBM. These results demonstrated that a diet containing BS12 FSBM improved growth performance by reducing dietary inflammation in piglets. ARTICLE HISTORY

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“…Only few recent studies explored the micro-scale structure of aerobic granules Ivanov et al, 2005;Wang et al, 2005;Chen et al, 2007a;Liu and Tay, 2007;Zheng and Yu, 2007). The majority of these studies focussed on extracellular polymeric substances (EPS) and its distribution within aerobic granules since nonbiodegradable EPS appear to provide an architectural structure and mechanical stability for such granules .…”

Section: Introductionmentioning

confidence: 99%

Micro-scale observations of the structure of aerobic microbial granules used for the treatment of nutrient-rich industrial wastewater

2008

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The structure and function of aerobic microbial granules from a lab-scale sequencing batch reactor treating nutrient-rich abattoir wastewater were investigated. These wastewater-fed granules were examined using a wide range of micro-scale techniques including light microscopy, scanning and transmission electron microscopy, fluorescent in situ hybridisation (FISH) combined with confocal laser scanning microscopy and oxygen and pH microsensors, in conjunction with a range of measurements in the bulk liquid phase. Interesting structural features were observed in these granules that have not been reported in synthetic-fed granules. The complex nature of abattoir wastewater was suggested to be responsible for accelerating the breaking process of large mature granules due to a rapid clogging of the granules pores and channels and for the very diverse microbial community observed displaying specific spatial distribution throughout the granules. More importantly, the dissolution at lower pH of mineral complexes associated to the granule matrix of extracellular polymeric substances might have caused the structural damages observed on the granules even though some pH buffer capacity was observed inside these granules. Ciliate protozoa were found to be very abundant on the surface of these wastewater-fed granules, which could potentially assist with reducing the high levels of suspended solids usually present in the aerobic granular sludge effluent. All these observations provide support to future studies on aerobic granular sludge treating real wastewater especially with regard to the granule structure and the mechanisms involved in their formation.

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Distribution of extracellular polymeric substances in aerobic granules

Cited by 205 publications

References 25 publications

Biofilm streamers cause catastrophic disruption of flow with consequences for environmental and medical systems

Biofilm streamers cause catastrophic disruption of flow with consequences for environmental and medical systems

Effect of soybean meal fermented with Bacillus subtilis BS12 on growth performance and small intestinal immune status of piglets

Micro-scale observations of the structure of aerobic microbial granules used for the treatment of nutrient-rich industrial wastewater

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