Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewat...Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.展开更多
Extracellular polymeric substances(EPS)are an importantmedium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron(oxyhydr)oxides production wh...Extracellular polymeric substances(EPS)are an importantmedium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron(oxyhydr)oxides production which reduced arsenic(As)availability.The main component of EPS secreted by iron-oxidizing bacteria(Ochrobactrum EEELCW01)was composed of polysaccharides(150.76-165.33 mg/g DW)followed by considerably smaller amounts of proteins(12.98–16.12 mg/g DW).Low concentrations of As(100 or 500μmol/L)promoted the amount of EPS secretion.FTIR results showed that EPS was composed of polysaccharides,proteins,and a miniscule amount of nucleic acids.The functional groups including-COOH,-OH,-NH,-C=O,and-C-O played an important role in the adsorption of As.XPS results showed that As was bound to EPS in the form of As3+.With increasing As concentration,the proportion of As3+adsorbed on EPS increased.Ferrihydrite with a weak crystalline state was only produced in the system at 6 hr during the mineralization process of Ochrobactrum sp.At day 8,the minerals were composed of goethite,galena,and siderite.With the increasing mineralization time,the main mineral phases were transformed from weakly crystalline hydrous iron ore into higher crystallinity siderite(FeCO_(3))or goethite(α-FeOOH),and the specific surface area and active sites of minerals were reduced.It can be seen from the distribution of As elements that As is preferentially adsorbed on the edges of iron minerals.This study is potential to understand the biomineralizationmechanism of iron-oxidizing bacteria and As remediation in the environment.展开更多
Extracellular polymeric substances(EPS)constitutes crucial elements within bacterial biofilms,facili-tating accelerated antimicrobial resistance and conferring defense against the host's immune cells.Developing pr...Extracellular polymeric substances(EPS)constitutes crucial elements within bacterial biofilms,facili-tating accelerated antimicrobial resistance and conferring defense against the host's immune cells.Developing precise and effective antibiofilm approaches and strategies,tailored to the specific charac-teristics of EPS composition,can offer valuable insights for the creation of novel antimicrobial drugs.This,in turn,holds the potential to mitigate the alarming issue of bacterial drug resistance.Current analysis of EPS compositions relies heavily on colorimetric approaches with a significant bias,which is likely due to the selection of a standard compound and the cross-interference of various EPS compounds.Considering the pivotal role of EPS in biofilm functionality,it is imperative for EPS research to delve deeper into the analysis of intricate compositions,moving beyond the current focus on polymeric materials.This ne-cessitates a shift from heavy reliance on colorimetric analytic methods to more comprehensive and nuanced analytical approaches.In this study,we have provided a comprehensive summary of existing analytical methods utilized in the characterization of EPS compositions.Additionally,novel strategies aimed at targeting EPS to enhance biofilm penetration were explored,with a specific focus on high-lighting the limitations associated with colorimetric methods.Furthermore,we have outlined the challenges faced in identifying additional components of EPS and propose a prospective research plan to address these challenges.This review has the potential to guide future researchers in the search for novel compounds capable of suppressing EPS,thereby inhibiting biofilm formation.This insight opens up a new avenue for exploration within this research domain.展开更多
The composition of tightly bound exopolymeric substances (EPS) obtained from biofilm and plan- ktonic cell subpopulations of Stenotrophomonas maltophilia 5426 UKM was analyzed to study an impact of mild steel presence...The composition of tightly bound exopolymeric substances (EPS) obtained from biofilm and plan- ktonic cell subpopulations of Stenotrophomonas maltophilia 5426 UKM was analyzed to study an impact of mild steel presence in the cultivation medium. The overall protein production was found to increase in the presence of a steel coupon. Some amino acids such as lysine, valine, iso-leucine, tyrosine and phenylalanine were found to be secreted in higher amounts in the presence of mild steel, while its absence leads to an increase of arginine, asparagine, serine, glutamine, proline, glycine, cysteine, leucine, methionine production levels. Biofilm cells EPS contained more arginine, glycine, cysteine, valine, methionine and leucine, comparing to EPS of planktonic cells. The chang- es of tightly bound EPS aggregation around the cells induced in the presence of steel coupons were revealed by transmission electron microscopy. The results suggested the transition of S. maltophilia 5426 UKM cells from planktonic to biofilm lifestyle to be a complex process involving more than a single step.展开更多
To integrate insulation and load-bearing functions in prefabricated composite wall structures,a novel design based on fiber-reinforced expanded polystyrene(EPS)con-crete is proposed.The research focuses on three key a...To integrate insulation and load-bearing functions in prefabricated composite wall structures,a novel design based on fiber-reinforced expanded polystyrene(EPS)con-crete is proposed.The research focuses on three key as-pects:material properties,seismic performance,and ther-mal performance.Firstly,the compressive strength and thermal conductivity of fiber-reinforced EPS concrete were analyzed at different sand ratios,leading to the development of an optimal mix design and a damage constitutive model.Secondly,a combination of experimental and numerical analysis methods was used to investigate the seismic perfor-mance of prefabricated composite walls with different infill materials,including autoclaved aerated fly ash and fiber-reinforced EPS concrete.Finally,thermal perfor-mance studies were conducted on prefabricated composite wall panels with different infill materials.The results indi-cate that the specimens underwent elastic,elastoplastic,and failure stages during loading.While specimens using EPS concrete exhibited a slightly lower overall bearing capacity,they demonstrated superior ductility,energy dissipation ca-pacity,and enhanced insulation and thermal stability.展开更多
BACKGROUND Fruits of Gardenia jasminoides(G.jasminoides)have extremely high medicinal value.However,the quality and traits of the plants vary significantly based on their provenances.In addition,the behaviour of the k...BACKGROUND Fruits of Gardenia jasminoides(G.jasminoides)have extremely high medicinal value.However,the quality and traits of the plants vary significantly based on their provenances.In addition,the behaviour of the known bioactive components,such as geniposide and crocin,has been the primary focus of the research on G.jasminoides.However,the identification of unknown bioactive components and their metabolomics remains underexplored.Therefore,analysing the metabolic differences between gardenias from different sources is essential to provide a comprehensive theoretical basis for the evaluation of G.jasminoides and germplasm resource identification.AIM To systematically evaluate the morphology,secondary metabolites,typical active ingredients,and antioxidant activity of wild G.jasminoides fruits.METHODS Gardenia fruits were collected from different provenances.Metabolites were identified via ultra-high-performance liquid chromatography–tandem mass spectrometry(UPLC-MS/MS).The metabolic differences were compared using hierarchical cluster analysis(HCA).The antioxidant capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays and ferric reducing antioxidant power assays,and its correlation with typical active ingredients was analysed.RESULTS A total of 444 and 240 metabolites were identified using UPLC-MS/MS in positive and negative ion modes,respectively.The HCA results of the flavonoids indicated that the higher content of flavonoids was in the fruits from Lukou.The differential analysis of metabolites in fruits from Shaoyang,Miluo and Lukou showed that the fruit from Miluo had the highest upregulated differential metabolites.CONCLUSION The metabolic characteristics of the Ningxiang and Xiangxi extracts were similar,while those of Lukou,Miluo and Shaoyang extracts differed significantly.展开更多
In the context of global COVID-19 epidemic preparedness,the extensive use of disposable surgical masks(DSM)may lead to its emergence as a main new source of microplastics in the environment.Nowadays,DSMs have become a...In the context of global COVID-19 epidemic preparedness,the extensive use of disposable surgical masks(DSM)may lead to its emergence as a main new source of microplastics in the environment.Nowadays,DSMs have become a non-negligible source of plastic waste in aquatic environment,however,less research has been done on DSM after biofilm colonization in freshwater environment.The study investigated the microbial community of DSM-associated biofilms by 16S rRNA gene sequencing.Analysis of the microbial community in the middle and inner/outer layers of the DSM showed that the middle layer was different from the remaining two layers and that potential pathogens were enriched only in the middle layer of the DSM.Herein,we focused on the middle layer and explored the characterization properties and extracellular polymeric substances(EPS)components changes during biofilm formation.The results showed that the EPS components varied with the biofilm incubation time.As the formation of biofilm,the protein(PN)and polysaccharide(PS)in EPS showed an overall increasing trend,and the growth of PS was well synchronized with PN.Three fluorescent components of EPS were determined by the three-dimensional excitation emission matrix(3D-EEM),including humic acid-like,fulvic acid-like,and aromatic protein-like components.The percentage of fluorescent components varied with increasing biofilm development time and then stabilized.Fourier transform infrared spectroscopy(FTIR)characterization results elucidated the emergence of oxygen-containing functional groups during biofilm formation.Moreover,the hydrophilicity increased with biofilm development.In conclusion,the environmental behavior and ecological risks of DSM in aquatic environment deserve urgent attention in future studies.展开更多
基金The National Natural Science Foundation of China (No. 50578053) and the Harbin Young Scientist Fund (No. 2003AFXXJ025)
文摘Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.
基金supported by the National Natural Science Foundation of China(No.42177392)the Dean’s Research Fund 2020/21(No.04626)of the Education University of Hong Kong.
文摘Extracellular polymeric substances(EPS)are an importantmedium for communication and material exchange between iron-oxidizing bacteria and the external environment and could induce the iron(oxyhydr)oxides production which reduced arsenic(As)availability.The main component of EPS secreted by iron-oxidizing bacteria(Ochrobactrum EEELCW01)was composed of polysaccharides(150.76-165.33 mg/g DW)followed by considerably smaller amounts of proteins(12.98–16.12 mg/g DW).Low concentrations of As(100 or 500μmol/L)promoted the amount of EPS secretion.FTIR results showed that EPS was composed of polysaccharides,proteins,and a miniscule amount of nucleic acids.The functional groups including-COOH,-OH,-NH,-C=O,and-C-O played an important role in the adsorption of As.XPS results showed that As was bound to EPS in the form of As3+.With increasing As concentration,the proportion of As3+adsorbed on EPS increased.Ferrihydrite with a weak crystalline state was only produced in the system at 6 hr during the mineralization process of Ochrobactrum sp.At day 8,the minerals were composed of goethite,galena,and siderite.With the increasing mineralization time,the main mineral phases were transformed from weakly crystalline hydrous iron ore into higher crystallinity siderite(FeCO_(3))or goethite(α-FeOOH),and the specific surface area and active sites of minerals were reduced.It can be seen from the distribution of As elements that As is preferentially adsorbed on the edges of iron minerals.This study is potential to understand the biomineralizationmechanism of iron-oxidizing bacteria and As remediation in the environment.
基金funded by the National Natural Science Foundation of China(Grant Nos.:81803812,81803237).
文摘Extracellular polymeric substances(EPS)constitutes crucial elements within bacterial biofilms,facili-tating accelerated antimicrobial resistance and conferring defense against the host's immune cells.Developing precise and effective antibiofilm approaches and strategies,tailored to the specific charac-teristics of EPS composition,can offer valuable insights for the creation of novel antimicrobial drugs.This,in turn,holds the potential to mitigate the alarming issue of bacterial drug resistance.Current analysis of EPS compositions relies heavily on colorimetric approaches with a significant bias,which is likely due to the selection of a standard compound and the cross-interference of various EPS compounds.Considering the pivotal role of EPS in biofilm functionality,it is imperative for EPS research to delve deeper into the analysis of intricate compositions,moving beyond the current focus on polymeric materials.This ne-cessitates a shift from heavy reliance on colorimetric analytic methods to more comprehensive and nuanced analytical approaches.In this study,we have provided a comprehensive summary of existing analytical methods utilized in the characterization of EPS compositions.Additionally,novel strategies aimed at targeting EPS to enhance biofilm penetration were explored,with a specific focus on high-lighting the limitations associated with colorimetric methods.Furthermore,we have outlined the challenges faced in identifying additional components of EPS and propose a prospective research plan to address these challenges.This review has the potential to guide future researchers in the search for novel compounds capable of suppressing EPS,thereby inhibiting biofilm formation.This insight opens up a new avenue for exploration within this research domain.
文摘The composition of tightly bound exopolymeric substances (EPS) obtained from biofilm and plan- ktonic cell subpopulations of Stenotrophomonas maltophilia 5426 UKM was analyzed to study an impact of mild steel presence in the cultivation medium. The overall protein production was found to increase in the presence of a steel coupon. Some amino acids such as lysine, valine, iso-leucine, tyrosine and phenylalanine were found to be secreted in higher amounts in the presence of mild steel, while its absence leads to an increase of arginine, asparagine, serine, glutamine, proline, glycine, cysteine, leucine, methionine production levels. Biofilm cells EPS contained more arginine, glycine, cysteine, valine, methionine and leucine, comparing to EPS of planktonic cells. The chang- es of tightly bound EPS aggregation around the cells induced in the presence of steel coupons were revealed by transmission electron microscopy. The results suggested the transition of S. maltophilia 5426 UKM cells from planktonic to biofilm lifestyle to be a complex process involving more than a single step.
基金The National Natural Science Foundation of China (No. 52168022)。
文摘To integrate insulation and load-bearing functions in prefabricated composite wall structures,a novel design based on fiber-reinforced expanded polystyrene(EPS)con-crete is proposed.The research focuses on three key as-pects:material properties,seismic performance,and ther-mal performance.Firstly,the compressive strength and thermal conductivity of fiber-reinforced EPS concrete were analyzed at different sand ratios,leading to the development of an optimal mix design and a damage constitutive model.Secondly,a combination of experimental and numerical analysis methods was used to investigate the seismic perfor-mance of prefabricated composite walls with different infill materials,including autoclaved aerated fly ash and fiber-reinforced EPS concrete.Finally,thermal perfor-mance studies were conducted on prefabricated composite wall panels with different infill materials.The results indi-cate that the specimens underwent elastic,elastoplastic,and failure stages during loading.While specimens using EPS concrete exhibited a slightly lower overall bearing capacity,they demonstrated superior ductility,energy dissipation ca-pacity,and enhanced insulation and thermal stability.
基金Supported by The Forestry Science and Technology Innovation Funded Project of Hunan Forestry Bureau,No.XLKY202221。
文摘BACKGROUND Fruits of Gardenia jasminoides(G.jasminoides)have extremely high medicinal value.However,the quality and traits of the plants vary significantly based on their provenances.In addition,the behaviour of the known bioactive components,such as geniposide and crocin,has been the primary focus of the research on G.jasminoides.However,the identification of unknown bioactive components and their metabolomics remains underexplored.Therefore,analysing the metabolic differences between gardenias from different sources is essential to provide a comprehensive theoretical basis for the evaluation of G.jasminoides and germplasm resource identification.AIM To systematically evaluate the morphology,secondary metabolites,typical active ingredients,and antioxidant activity of wild G.jasminoides fruits.METHODS Gardenia fruits were collected from different provenances.Metabolites were identified via ultra-high-performance liquid chromatography–tandem mass spectrometry(UPLC-MS/MS).The metabolic differences were compared using hierarchical cluster analysis(HCA).The antioxidant capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays and ferric reducing antioxidant power assays,and its correlation with typical active ingredients was analysed.RESULTS A total of 444 and 240 metabolites were identified using UPLC-MS/MS in positive and negative ion modes,respectively.The HCA results of the flavonoids indicated that the higher content of flavonoids was in the fruits from Lukou.The differential analysis of metabolites in fruits from Shaoyang,Miluo and Lukou showed that the fruit from Miluo had the highest upregulated differential metabolites.CONCLUSION The metabolic characteristics of the Ningxiang and Xiangxi extracts were similar,while those of Lukou,Miluo and Shaoyang extracts differed significantly.
基金Supported by the Natural Science Foundation of Shandong Province(Nos.ZR2022MD115,ZR202111160067)。
文摘In the context of global COVID-19 epidemic preparedness,the extensive use of disposable surgical masks(DSM)may lead to its emergence as a main new source of microplastics in the environment.Nowadays,DSMs have become a non-negligible source of plastic waste in aquatic environment,however,less research has been done on DSM after biofilm colonization in freshwater environment.The study investigated the microbial community of DSM-associated biofilms by 16S rRNA gene sequencing.Analysis of the microbial community in the middle and inner/outer layers of the DSM showed that the middle layer was different from the remaining two layers and that potential pathogens were enriched only in the middle layer of the DSM.Herein,we focused on the middle layer and explored the characterization properties and extracellular polymeric substances(EPS)components changes during biofilm formation.The results showed that the EPS components varied with the biofilm incubation time.As the formation of biofilm,the protein(PN)and polysaccharide(PS)in EPS showed an overall increasing trend,and the growth of PS was well synchronized with PN.Three fluorescent components of EPS were determined by the three-dimensional excitation emission matrix(3D-EEM),including humic acid-like,fulvic acid-like,and aromatic protein-like components.The percentage of fluorescent components varied with increasing biofilm development time and then stabilized.Fourier transform infrared spectroscopy(FTIR)characterization results elucidated the emergence of oxygen-containing functional groups during biofilm formation.Moreover,the hydrophilicity increased with biofilm development.In conclusion,the environmental behavior and ecological risks of DSM in aquatic environment deserve urgent attention in future studies.
