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Extracellular polymeric substances (EPS) released by bacteria play a crucial role in microbial aggregation during wastewater treatment. Various environmental factors including ...substrate, anaerobic and aerobic conditions might contribute to the formation and properties of EPS, and thereby affect the properties of microbial aggregation and sludge. To reveal the relationship between these environmental factors and EPS properties, the characteristics of EPS generated in four types of sludge were investigated, including anammox granular sludge (ANMX), aerobic granular sludge (AGS) fed with glucose as carbon source (AGS-GLUC), AGS fed with liquor wastewater as carbon source (AGS-LIQ), and flocculent sludge from a real sewage plant (FLOC). Results indicated a positive correlation of EPS contents with granulation of sludge. As the dominant content of EPS, an increased proteins (PN) concentration facilitated the formation of microbial aggregates and the granulation of sludge. Bacteria in anaerobic environment (i.e., ANMX) or in aerobic environment with easily biodegradable carbon sources (i.e., AGS-GLUC) would generate more PN and EPS; yet, these conditions restrained the generation of humic acid (HA). The sludge from the sewage treatment plant (i.e., FLOC) had the lowest EPS and PN content, but the highest HA, showing flocculent structure sludge. In addition, a higher protein/polysaccharide (PN/PS) ratio and a lower zeta potential of EPS were conductive to sludge granulation. The hydrophobicity of EPS confirmed via analysis of chemical structures by FTIR would improve the microbial aggregation.
Spatial organization of chromatin contributes to gene regulation of many cellular processes and includes a connection of chromatin with the nuclear lamina (NL). The NL is a protein mesh that resides ...underneath the inner nuclear membrane and consists of lamins and lamina-associated proteins. Chromatin regions associated with lamins in animals are characterized mostly by constitutive heterochromatin, but association with facultative heterochromatin mediated by Polycomb-group (PcG) proteins has been reported as well. In contrast with animals, plant NL components are largely not conserved and NL association with chromatin is poorly explored. Here, we present the connection between the lamin-like protein, CROWDED NUCLEI1 (CRWN1), and the chromatin- and PcG-associated component, PROLINE-TRYPTOPHANE-TRYPTOPHANE-PROLINE INTERACTOR OF POLYCOMBS1, in Arabidopsis (
). We show that PWO1 and CRWN1 proteins associate physically with each other, act in the same pathway to maintain nuclear morphology, and control expression of a similar set of target genes. Moreover, we demonstrate that transiently expressed PWO1 proteins form foci located partially at the subnuclear periphery. Ultimately, as CRWN1 and PWO1 are plant-specific, our results argue that plants might have developed an equivalent, rather than homologous, mechanism of linking chromatin repression and NL.
Microbial cells (i.e., bacteria, archaea, microeukaryotes) in oceans secrete a diverse array of large molecules, collectively called extracellular polymeric substances (EPSs) or simply
. These ...secretions facilitate attachment to surfaces that lead to the formation of structured '
' communities. In open-water environments, they also lead to formation of organic colloids, and larger aggregations of cells, called '
Secretion of EPS is now recognized as a fundamental microbial adaptation, occurring under many environmental conditions, and one that influences many ocean processes. This relatively recent realization has revolutionized our understanding of microbial impacts on ocean systems. EPS occur in a range of molecular sizes, conformations and physical/chemical properties, and polysaccharides, proteins, lipids, and even nucleic acids are actively secreted components. Interestingly, however, the physical ultrastructure of how individual EPS interact with each other is poorly understood. Together, the EPS matrix molecules form a three-dimensional architecture from which cells may localize extracellular activities and conduct cooperative/antagonistic interactions that cannot be accomplished efficiently by free-living cells. EPS alter optical signatures of sediments and seawater, and are involved in biogeomineral precipitation and the construction of microbial macrostructures, and horizontal-transfers of genetic information. In the water-column, they contribute to the formation of marine snow, transparent exopolymer particles (TEPs), sea-surface microlayer biofilm, and marine oil snow. Excessive production of EPS occurs during later-stages of phytoplankton blooms as an excess metabolic by product and releases a carbon pool that transitions among dissolved-, colloidal-, and gel-states. Some EPS are highly labile carbon forms, while other forms appear quite refractory to degradation. Emerging studies suggest that EPS contribute to efficient trophic-transfer of environmental contaminants, and may provide a protective refugia for pathogenic cells within marine systems; one that enhances their survival/persistence. Finally, these secretions are prominent in 'extreme' environments ranging from sea-ice communities to hypersaline systems to the high-temperatures/pressures of hydrothermal-vent systems. This overview summarizes some of the roles of exopolymer in oceans.
The problem of management and treatment of wastewater from commercial laundries is a matter of concern. The present study provides an effective and eco-friendly solution to the treatment of ...wastewater from commercial laundries in Quebec (Canada) by using the extracellular polymeric substance (EPS) as a bio-flocculant. EPS was produced from the valorization of crude glycerol and paper mill sludge by a bacterial strain (BS-04). Two different types of EPS: Slime EPS (S-EPS) and Broth EPS (B-EPS) were used for the treatment of commercial laundry wastewater (CLWW). This is the first study for the treatment of CLWW using bio-flocculant EPS. A comparison between the conventional treatment of laundry wastewater (LWW) by chemical coagulants (FeSO
4
, CaCl
2
, Alum) and enhanced treatment by bio-flocculant EPS has been drawn in the study. Moreover, LWW treatment by a combination of EPS and chemical coagulants was also investigated. It was observed that S-EPS (0.6 g/L) gave better flocculation activity (FA) than B-EPS. S-EPS alone can remove 83.20% of turbidity, 77.69% of suspended solids (SS), and 76.37% of chemical oxygen demand (COD). The best results were obtained by combining S-EPS (0.6 g/L) with alum (300 mg/L) at pH 7 for a treatment time of 30 min. This combination was able to remove 98% of turbidity, 95.42% of SS, and 83.08% of COD from LWW. When treatment time has been increased to 4 h at pH 7, it resulted in more than 88% COD removal from CLWW.
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•EL/EC and ZVI activated persulfate had synergetic effect on sludge dewatering.•EZP conditioning effectively enhanced different types of sludge dewaterability.•EZP oxidation destroyed ...the EPS and cells, releasing bound water in sludge flocs.•Degradation of protein-like substances contributed to sludge dewatering.•Cost of EZP conditioning saving up to 41.9% in comparison with Fenton method.
Waste activated sludge (WAS) is difficult to be dewatered due to the highly water bounded in sludge flocs, and the extracellular polymeric substances (EPS) was the major factor affecting sludge dewatering performance. In this study, the hybrid process of electrolysis/electrocoagulation and zero-valent iron activated persulfate oxidation (EZP) showed a significant synergetic effect in enhancing municipal sludge dewaterability, and has the potential for enhancing industrial sludge dewaterability. The optimal dewatering conditions for municipal sludge were voltage 40V and 4.15g/L Na2S2O8 when zero-valent iron induced electrodes were applied. After EZP pretreatment, the municipal sludge specific resistance to filtration (SRF) and capillary suction time (CST) decreased by 87.4% and 49.1% respectively. The effects of EZP pretreatment on zeta potential, EPS property, viscosity and dewaterability of different sludge were analyzed to unravel the underlying mechanism of sludge conditioning. Results showed that the EZP oxidation was capable to effectively disrupt the EPS, crack the entrapped cells, and degrade the protein-like substances, reducing the viscosity and negative zeta potential, releasing bound water inside EPS and cells and thus improving sludge dewaterability. According to the analysis of Three-dimensional excitation emission matrix (3D-EEM), the EZP technology greatly decomposed tryptophan and aromatic protein-like substances in EPS. Scanning electron microscope (SEM) analysis further revealed that the disrupted EPS and cells were coagulated after EZP conditioning and reinforced sludge dewatering. The preliminary economic analysis showed that the optimized EZP was economically favorable.
A wide range of microorganisms produce extracellular polymeric substances (EPS), highly hydrated polymers that are mainly composed of polysaccharides, proteins, and DNA. EPS are fundamental for ...microbial life and provide an ideal environment for chemical reactions, nutrient entrapment, and protection against environmental stresses such as salinity and drought. Microbial EPS can enhance the aggregation of soil particles and benefit plants by maintaining the moisture of the environment and trapping nutrients. In addition, EPS have unique characteristics, such as biocompatibility, gelling, and thickening capabilities, with industrial applications. However, despite decades of research on the industrial potential of EPS, only a few polymers are widely used in different areas, especially in agriculture. This review provides an overview of current knowledge on the ecological functions of microbial EPSs and their application in agricultural soils to improve soil particle aggregation, an important factor for soil structure, health, and fertility.
The production and composition of extracellular polymeric substances (EPS) are important parameters of bioreactor performance. This study compared the characteristics of EPS of nitritation- and ...nitrification-dominant processes in an integrated fixed-film activated sludge reactor. The results showed that the tightly bound-EPS (TB-EPS) were composed of polysaccharides and protein in variable ratios, while loosely bound-EPS (LB-EPS) contains almost no protein. Quartz crystal microbalance with dissipation studies demonstrated that the adsorption of TB-EPS to solid surface was stronger and less reversible as compared to the LB-EPS, which demonstrated the importance of protein in cell adhesion. Under nitritation condition, higher abundance of ammonia oxidizing bacteria was detected, and higher amide or amine like and aromatic and tryptophan protein like substances contents in TB-EPS was also observed. The other key finding is that when nitritaion was achieved, a decrease in the abundance of nitrite oxidizing bacteria and lower hydrocarbon-like substance and humic acid-like substances in the TB-EPS were observed.
Cleomaceae is a diverse group well-suited to addressing fundamental genomicand evolutionary questions as the sister group to Brassicaceae, facilitatingtransfer of knowledge from the model Arabidopsis ...thaliana. Phylogenetic andtaxonomic revisions provide a framework for examining the evolution of substantive morphological and physiology diversity in Cleomaceae, but not necessarily in Brassicaceae. The investigation of both nested and contrastingwhole-genome duplications (WGDs) between Cleomaceae and Brassicaceaeallows comparisons of independently duplicated genes and investigation ofwhether they may be drivers of the observed innovations. Further, a wealth ofoutstanding genetic research has provided insight into how the importantalternative carbon fixation pathway, C4 photosynthesis, has evolved via differential expression of a suite of genes, of which the underlying mechanisms are being elucidated.
•The EPS- Ca6 is a polymer of glucose by α (1→6) linkage.•The EPS-Ca6 showed a potential antioxidant activity.•The EPS-Ca6 exhibited significant antibacterial activity against pathogenic ...bacteria.•The EPS-Ca6 accelerated significantly rat wound healing activity after 14 days.
The present study aimed to evaluate the in vitro antibacterial and antioxidant activities and the in vivo wound healing performance of a noval exopolysaccharides (EPS-Ca6) produced by Lactobacillus sp.Ca6 strain. The results showed that EPS-Ca6 had a potential antioxidant activity determined through four different assays: DPPH scavenging activity, reducing power, β-carotene bleaching by linoleic acid assay, and Metal chelating activities. It also exhibited significant antibacterial activity against pathogenic bacteria Salmonella enterica and Micrococcus luteus. The wound healing activity of the EPS-Ca6, using excision wound model in rats, showed that this novel EPS accelerated significantly wound healing activity as compared to the control group, and a total closure was achieved after 14days of wound induction. Furthermore, histological examination of biopsies showed fully re-epithelialized wound with a complete epidermal regeneration. Overall the finding indicates that the EPS-Ca6 might be useful as a wound healing agent in modern medicine.
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