Opposite to the significant knowledge about the toxicity of AgNPs to phytoplankton species, rather limited knowledge is available about the role of phytoplankton secretions such as extracellular ...polymer substances (EPS) in NPs’ fate ...
The increasing water pollution caused by the presence of nano- and microplastics has shown a need to pursue solutions to remediate this problem. In this work, an extracellular polymeric substance ...(EPS) producing freshwater Cyanothece sp. strain was exposed to nano- and microplastics. The bioflocculant capacity of the biopolymer produced was evaluated. The influence of different concentrations (1 and 10 mg L−1) of polystyrene nano- and microplastics in the extracellular carbohydrates and in the EPS production was studied. The presence of nano- and microplastics induced a negative effect on the microalgal growth (of up to 47%). The results show that the EPS produced by Cyanothece sp. exhibits high bioflocculant activity in low concentrations. Also, the EPS displayed very favourable characteristics for aggregation, as the aggregates were confirmed to consist of microalga, EPS and both the nano- and microplastics. These results highlight the potential of the microalgal-based biopolymers to replace hazardous synthetic flocculants used in wastewater treatment, while aggregating and flocculating nano- and microplastics, demonstrating to be a multi-purposed, compelling, biocompatible solution to nano- and microplastic pollution.
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•Cyanothece sp. EPS show the ability to heavily aggregate PS nano- and microplastics.•Cyanothece sp. EPS show high bioflocculant activity, even in low concentrations.•Cyanothece sp. EPS can be used in wastewater nano- and microplastics bioremediation.
With the development of the sustainable cement industry, the self-healing properties of concrete have received widespread attention. In many studies, both microorganisms and fibers play an important ...role in promoting the self-healing ability of concrete. In particular, some recent studies have tried to load microorganisms with fibers for improving the self-healing ability of concrete; and these studies believe that the combination of fibers and microbes accelerates the self-repair process. However, this process has not been characterized and the mechanism has not been explored. This paper investigated the mechanism of the coupled effect of fiber and bacteria on self-healing efficiency of concrete. The results confirmed that the coupled effect of bacteria and fiber could result in higher repair efficiency, better mechanical properties and water resistance recovery. In addition, the significance of EPS in inducing the deposition of calcium carbonates on fibers was determined by analyzing the induction effects of microbial cells and EPS respectively. Finally, biological staining was used to observe the role of biological organic matter in the repairing process.
•Incorporating polypropylene (PP) fibers and bacteria could improve repairing efficiency of concrete.•The combination of fibers and microorganisms can capture calcium ions dissolved from cracks to improve repair efficiency.•Bacterial extracellular polymeric substances play an important role in the coupled effect.
●SMP and EPS could be used as denitrifying carbon sources by strain RT1901.●Whole-genome sequence of Thauera sp. RT1901 revealed diverse metabolism.●The abundance of traditional PAOs decreased with ...the enrichment of Thauera.●The removal rates of COD and TN increased with the enrichment of Thauera.
Thauera, as one of the core members of wastewater biological treatment systems, plays an important role in the process of nitrogen and phosphorus removal from low-carbon source sewage. However, there is a lack of systematic understanding of Thauera’s metabolic pathway and genomics. Here we report on the newly isolated Thauera sp. RT1901, which is capable of denitrification using variety carbon sources including aromatic compounds. By comparing the denitrification processes under the conditions of insufficient, adequate and surplus carbon sources, it was found that strain RT1901 could simultaneously use soluble microbial products (SMP) and extracellular polymeric substances (EPS) as electron donors for denitrification. Strain RT1901 was also found to be a denitrifying phosphate accumulating bacterium, able to use nitrate, nitrite, or oxygen as electron acceptors during poly-β-hydroxybutyrate (PHB) catabolism. The annotated genome was used to reconstruct the complete nitrogen and phosphorus metabolism pathways of RT1901. In the process of denitrifying phosphorus accumulation, glycolysis was the only pathway for glycogen metabolism, and the glyoxylic acid cycle replaced the tricarboxylic acid cycle (TCA) to supplement the reduced energy. In addition, the abundance of conventional phosphorus accumulating bacteria decreased significantly and the removal rates of total nitrogen (TN) and chemical oxygen demand (COD) increased after the addition of RT1901 in the low carbon/nitrogen (C/N) ratio of anaerobic aerobic anoxic-sequencing batch reactor (AOA-SBR). This research indicated that the diverse metabolic capabilities of Thauera made it more competitive than other bacteria in the wastewater treatment system.
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This study determined the impact of changes in the Jakarta Islamic Index's Consumer Goods sector's Earnings Per Share, Return on Equity, and Gross Domestic Product from 2018 to 2020. This work uses ...panel data regression analysis and quantitative research techniques with secondary data. A purposive sampling method, or sample selection strategy based on several variables, was employed to choose the sample of firms in the consumer goods sector represented in the JII index. The F test results indicate that from 2018 to 2020, GDP, EPS, and ROE can impact the share price of JII issuers. According to the T-test, only EPS may have an enormous positive impact on stock prices, whereas ROE has a significant negative effect. GDP demonstrates that from 2018 to 2020, firms' stock prices in the consumer goods sector listed on JII are unaffected by GDP.
The adsorption behavior and interaction mechanisms of extracellular polymeric substances (EPS) of Pseudomonas aeruginosa OMCS-1 towards chromium (Cr), lead (Pb), and cadmium (Cd) were investigated. ...EPS-covered (EPS-C) cells exhibited significantly higher (p < 0.0001; two-way ANOVA) removal of Cr (85.58 ± 0.39%), Pb (81.98 ± 1.02%), and Cd (73.88 ± 1%) than EPS-removed (EPS-R) cells. Interactions between EPS-heavy metals were spontaneous (ΔG<0). EPS-Cr(VI) and EPS-Pb(II) binding were exothermic (ΔH<0), while EPS-Cd(II) binding was endothermic (ΔH>0) process. EPS bonded to Pb(II) via inner-sphere complexation by displacement of surrounding water molecules, while EPS-Cr(VI) and EPS-Cd(II) binding occurred through outer-sphere complexation via electrostatic interactions. Increased zeta potential of Cr (29.75%), Pb (41.46%), and Cd (46.83%) treated EPS and unchanged crystallinity (CIXRD=0.13), inferred EPS-metal binding via both electrostatic interactions and complexation mechanism. EPS-metal interaction was predominantly promoted through hydroxyl, amide, carboxyl, and phosphate groups. Metal adsorption deviated EPS protein secondary structures. Strong static quenching mechanism between tryptophan protein-like substances in EPS and heavy metals was evidenced. EPS sequestered heavy metals via complexation with C-O, C-OH, CO/O-C-O, and NH/NH2 groups and ion exchange with –COOH group. This study unveils the fate of Cr, Pb, and Cd on EPS surface and provides insight into the interactions among EPS and metal ions for metal sequestration.
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•The presence of EPS on bacterial surface facilitates the adsorption of metal ions.•EPS-metal binding was spontaneous, exothermic for Cr and Pb, and endothermic for Cd.•Electrostatic interaction and complexation mechanism of EPS and metal binding.•Heavy metal adsorption deviated the secondary structures of EPS proteins.•Static quenching mechanism between tryptophan containing proteins and heavy metals.
Microplastics (MPs) are ubiquitous in aquatic ecosystems and can significantly influence the growth, aggregation and functions of phytoplankton biomass. However, variations in the extracellular ...polymeric substances (EPS) of phytoplankton in terms of compositions and structures in response to MPs were still not reported. In this study, EPS matrix of Microsystis aeruginosa was applied and fractionated into loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) fractions, with the time-dependent changes in response to different concentrations (10, 100 and 500 mg/L) of MPs being explored via using the fluorescence excitation emission matrix coupled with parallel factor (EEM-PARAFAC) and two-dimensional Fourier transform infrared correlation spectroscopy (2D-FTIR-COS) analysis. Results showed that 500 mg/L of MP concentration significantly inhibited Microcystis growth by 30.5% but enhanced EPS secretion. In addition, organic composition in LB-EPS and TB-EPS varied differently in response to increased MP exposure, as the ratio of polysaccharide/protein increased in the TB-EPS but decreased in LB-EPS. Further analysis revealed obvious heterogeneities in organic component variations in response to MPs, as the C–O functional groups and glycosidic bonds in the TB-EPS preferentially responded, which lead to the domination of polysaccharides and humus substances; while the carbonyl, carboxyl and amino functional groups in the LB-EPS exhibited a preferential response, which caused the enhanced percentage of the tryptophan-like proteins. In addition to organic compositions, the aromaticity, hydrophobicity and humification in the LB-EPS fraction increased with enhanced MP exposure, which, as a result, may influence the ecotoxicological risk of MPs. Therefore, Microcystis can dynamically adjust not only the EPS contents but also the compositions in response to MPs exposure. The results can improve our understanding on the eco-physiological impact of phytoplankton-MP interaction in aquatic environment, and indicate that the dose-dependent and long-term effects of MPs on phytoplankton should be considered in future study.
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•Dynamic variations in EPS compositions and structures with microplastic exposure were studied.•500 mg/L of microplastics inhibited the Microcystis growth but promoted EPS production.•Polysaccharide/protein ratio increased in TB-EPS but decrease in LB-EPS with microplastic exposure.•Proteins with amide groups were secreted prior to humus in the TB-EPS fraction.•Oxygen-containing amide groups in LB-EPS were secreted prior to polysaccharides.
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•A novel exopolysaccharide (R-5-EPS) was obtained from Lactobacillus helveticus LZ-R-5.•R-5-EPS was a linear hetero-glucogalactan with average Mw of 5.41 × 105 Da.•Structure of ...R-5-EPS was composed of →3)-β-D-Glcp-(1→ and →6)-β-D-Galp-(1→ residues.•R-5-EPS showed potent macrophage immunomodulatory activity in vitro.
Exopolysaccharide (R-5-EPS) was isolated from the fermented milk of Lactobacillus helveticus LZ-R-5 and purified by DEAE-52 cellulose anion-exchange column, and characterization of the structure was conducted. Results showed that R-5-EPS was a heteropolysaccharide containing linear repeating units of →6)-β-D-Galp-(1→3)-β-D-Glcp-(1→3)-β-D-Glcp-(1→3)-β-D-Glcp-(1→3)-β-D-Glcp-(1→ with an average Mw of 5.41 × 105 Da. Furthermore, at a cellular level, R-5-EPS showed immunostimulatory activity due to its strong effect on increasing proliferation of RAW264.7 macrophages and enhancing phagocytosis, acid phosphatase activity, nitric oxide production and cytokines production in macrophages. These results suggest that R-5-EPS have a potent immunostimulatory activity and may be explored as a potential immunomodulatory agent.
Microbially secreted exopolymeric substances (EPS), rich in polysaccharides and proteins, make up an important part of natural organic matter in the ocean, especially marine snow. While the attention ...in the oceanographic literature is focused more on the role of polysaccharides and less of proteins in EPS functions, the role of proteins, especially the role of the protein/carbohydrate (P/C) ratio of particles and colloids (macromolecular fraction) remains to be explored. EPS associated with particles forms a biofilm, where proteins are not only involved in cell surface attachment, but also in the stabilization of the biofilm matrix, and the development of a three-dimensional biofilm architecture. Here, we provide a perspective based on the most recent literature on EPS, marine oil spills and waste water treatment to describe the relationship between the P/C ratio of EPS and a number of biophysical properties related to biopolymer aggregation propensity, e.g., relative hydrophobicity, surface activity and surface tension, attachment efficiency, light-induced chemical crosslinking, and sedimentation efficiency of marine snow in marine environments.
Many antibiotics, chemotherapeutics, crop protection agents and food preservatives originate from molecules produced by bacteria, fungi or plants. In recent years, genome mining methodologies have ...been widely adopted to identify and characterize the biosynthetic gene clusters encoding the production of such compounds. Since 2011, the 'antibiotics and secondary metabolite analysis shell-antiSMASH' has assisted researchers in efficiently performing this, both as a web server and a standalone tool. Here, we present the thoroughly updated antiSMASH version 4, which adds several novel features, including prediction of gene cluster boundaries using the ClusterFinder method or the newly integrated CASSIS algorithm, improved substrate specificity prediction for non-ribosomal peptide synthetase adenylation domains based on the new SANDPUMA algorithm, improved predictions for terpene and ribosomally synthesized and post-translationally modified peptides cluster products, reporting of sequence similarity to proteins encoded in experimentally characterized gene clusters on a per-protein basis and a domain-level alignment tool for comparative analysis of trans-AT polyketide synthase assembly line architectures. Additionally, several usability features have been updated and improved. Together, these improvements make antiSMASH up-to-date with the latest developments in natural product research and will further facilitate computational genome mining for the discovery of novel bioactive molecules.
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