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Method evaluation of extracellular polymeric substances extraction from Anammox granular sludge with compact structure
Full text linkAs a major component of the matrix in granular sludge (GS), extracellular polymeric substance (EPS) is
crucial in formation and stabilization of compact structure. Thus, the selection of appropriate extraction methods is of
great importance, affecting the yield, composition, and the properties of EPS. However, there is still lack of the standard
methods for EPS extraction. In present study, several commonly used methods were applied for extracting EPS
from anaerobic ammonium oxidation (Anammox) GS, and the effectiveness of these methods were evaluated. The
methods of heating, and formaldehyde with NaOH were found to obtain a higher EPS yield rate, compared to the other
methods. The collected EPS was found to mainly consist of proteins (PN) and polysaccharides (PS). The high PN/PS
values obtained in most methods indicated that protein content was substantially enriched in the granules. Moreover,
the dominance of amide bands and/or polysaccharide -associated bands in the EPS was also revealed in the results of
Attenuated total reflectance-Fourier transform infrared spectra
Extracellular polymeric substances as paper coating biomaterials derived from anaerobic granular sludge
Full text linkRecovering extracellular polymeric substances (EPS) from waste granular sludge offers a cost-effective and sustainable approach for transforming wastewater resources into industrially valuable products. Yet, the application potential of these EPS in real-world scenarios, particularly in paper manufacturing, remains underexplored. Here we show the feasibility of EPS-based biomaterials, derived from anaerobic granular sludges, as novel coating agents in paper production. We systematically characterised the rheological properties of various EPS-based suspensions. When applied as surface sizing agents, these EPS-based biomaterials formed a distinct, ultra-thin layer on paper, as evidenced by scanning electron microscopy. A comprehensive evaluation of water and oil penetration, along with barrier properties, revealed that EPS-enhanced coatings markedly diminished water absorption while significantly bolstering oil and grease resistance. Optimal performance was observed in EPS variants with elevated protein and hydrophobic contents, correlating with their superior rheological characteristics. The enhanced water-barrier and grease resistance of EPS-coated paper can be attributed to its non-porous, fine surface structure and the functional groups in EPS, particularly the high protein content and hydrophobic humic-like substances. This research marks the first demonstration of utilizing EPS from anaerobic granular sludge as paper-coating biomaterials, bridging a critical knowledge gap in the sustainable use of biopolymers in industrial applications
Analysis and characterization of extracellular polymeric substances extracted from anammox granules
No full textLAUREA MAGISTRALELe sostanze polimeriche extracellulari (EPS) sono composti naturali secreti dai batteri durante la loro attività metabolica. Questi polimeri svolgono diverse funzioni: essi proteggono i microrganismi da sostanze tossiche e condizioni ambientali sfavorevoli, consentono l'aggregazione in biofilm o granuli sospesi, favoriscono l'accumulo e l'assimilazione di nutrienti e vengono consumati in assenza di substrato. Gli EPS sono presenti in fanghi granulari nei reattori che effettuano l'ossidazione anaerobica dell'ammonio (Anammox).
L'obiettivo di questo studio è quello di analizzare diversi tipi di granuli da vari impianti di trattamento delle acque reflue (WWTP), confrontare le caratteristiche e la composizione degli EPS estratti e definire le correlazioni tra le caratteristiche dell'EPS e la dimensione dei granuli.
In questo studio vengono esaminati tre diversi tipi di granuli anammox, due provenienti da WWTP che trattano digestato da impianti di depurazione comunali con sede in Belgio e nei Paesi Bassi (Anammox Belgium - BL, e Anammox Netherlands - NL) e l'ultimo da un reattore su scala di laboratorio che tratta acqua reflua industriale proveniente da un’industria tessile (Textile Anammox - TEX). Sette campioni EPS sono stati estratti da questi granuli e analizzati per misurare la concentrazione totale di proteine (PN), polisaccaridi (PS) e citocromo-c e la loro distribuzione dimensionale polimerica al molecolar weight cut-off di 3, 30 e 100 kDa. Gli EPS sono stati estratti utilizzando il metodo di Na2CO3-heating e sono stati precedentemente sottoposti ad analisi qualitative di spettroscopia Ultravioletto-Visibile (UV-Vis) e matrice di fluorescenza di eccitazione/emissione (EEM).
I granuli studiati hanno mostrato una grande variabilità di dimensioni, che si estendono da un diametro medio da 1,8 a 6,1 mm. Il contenuto PN è simile in tutti gli EPS estratti e per la maggior parte queste catene polimeriche sono più grandi di 3 kDa, mentre la concentrazione di PS aumenta al diminuire della dimensione dei granuli e questi composti sono costituiti principalmente da lunghe catene polimeriche con dimensione >30 kDa.
L'analisi di fluorescenza mostra la presenza di sostanze umiche all'interno degli EPS. Il contenuto di eme-c è inferiore in TEX rispetto a BL e NL, dando loro un colore verde invece dell’usuale colore rossastro dei batteri anammox.
Le diverse caratteristiche dei granuli e dell'EPS possono essere dovute alle configurazioni dei vari reattori e dai loro parametri operativi, dai diversi nitrogen loading rate e la diversa composizione dell’acqua reflua municipale e industriale.Extracellular polymeric substances (EPS) are natural compounds secreted by bacteria during their metabolic activity. These polymers fulfill various functions: they protect microorganisms from toxic substances and unfavorable environmental conditions, allow aggregation into biofilms or suspended granules, help accumulate and assimilate nutrients, and are consumed in the absence of substrate. EPS are present in granular sludge in reactors performing the anaerobic oxidation of ammonium (Anammox).
The objective of this study is to analyze different types of granules from various wastewater treatment plants (WWTPs), compare the characteristics and composition of the extracted EPS, and find correlations between the EPS features and the size of the granules.
During this work, three different types of anammox granules are examined, two from depuration plants treating digestate from municipal WWTPs located in Belgium and the Netherlands (Anammox Belgium - BL, and Anammox Netherlands - NL) and the latest from a lab-scale reactor treating industrial wastewater from a textile industry (Textile Anammox - TEX). Seven EPS samples were extracted from these granules and analyzed to measure the total concentration of proteins (PN), polysaccharides (PS) and cytochrome-c, and their polymeric size distribution at the molecular weight cut-off of 3, 30, and 100 kDa. The EPS were extracted using the Na2CO3-heating method and were previously subjected to a qualitative Ultraviolet-Visible (UV-Vis) and excitation/emission fluorescence matrix (EEM) analyses.
The studied granules showed great variability in size, ranging from an average diameter of 1.8 to 6.1 mm. The PN content is similar in all the extracted EPS and most of these polymer chains are larger than 3 kDa, while the PS concentration increases as the granule size decreases and are mainly composed of long polymer chains with dimension >30 kDa. The fluorescence analysis shows the presence of humic-like substances inside the EPS. The heme-c content is lower in TEX than in BL and NL giving them a green color instead of the usual reddish color of anammox bacteria.
The different characteristics of granules and EPS may be due to the various reactor configurations and operational parameters, the different nitrogen loading rates, and the different composition between the digestate and the industrial wastewater
Extraction, recovery and characterisation of extracellular polymeric substances (EPS) of anammox and anaerobic granular sludge
Full text linkLAUREA MAGISTRALELe sostanze polimeriche extracellulari (EPS) sono polimeri naturali secreti da microorganismi, fra cui i batteri, nell’ambiente circostante. Le EPS proteggono gli organismi da condizioni ambientali avverse come la presenza di sostanze tossiche; garantiscono la stabilità cellulare; migliorano le proprietà di adsorbimento e adesione; rappresentano una fonte di carbonio ed energia. Le EPS sono presenti nei fanghi granulari sia nell'ossidazione anaerobica dell'ammonio (anammox) che nei processi anaerobici, due tecniche di trattamento delle acque reflue ampiamente adottate per la rimozione dell'azoto. L’obiettivo del lavoro è triplice: capire le caratteristiche delle EPS anammox, scoprirne la composizione, evidenziare le differenze fra le EPS dei fanghi granulari anammox e anarobici e correlare la qualità e il rendimento degli EPS anammox con le performance del reattore.
Durante il mio lavoro presso il Laboratorio di Ingegneria Ambientale (LIA) del Dipartimento di Ingegneria Civile e Ambientale (DICA) del Politecnico di Milano, sono stati estratti, analizzati e confrontati EPS sia da fanghi granulari anammox che anaerobici. In particolare, il lavoro è stato condotto su cinque campioni di anammox e su due anaerobici. Gli anammox sono stati raccolti mensilmente da luglio a dicembre da un reattore pilota di un’industria tessile nella zona di Como (Lombardia) mentre i granuli anaerobici provengono da due diversi impianti di trattamento delle acque reflue (WWTP) che trattano rispettivamente gli scarti di un birrificio e di un'industria cartaria. In primo luogo, è stato studiato il fango granulare, sia quantitativamente che qualitativamente. In seguito, abbiamo estratto le EPS utilizzando il metodo riscaldamento-Na2CO3 e calcolato le frazioni di polisaccaridi (PS) e proteine (PN) nelle EPS e la sua resa. Infine abbiamo effettuato la spettroscopia ultravioletta-visibile (UV-vis) e la caratterizzazione della frazione polimerica.
È stato concluso che i granuli di anammox sono più rossastri, più piccoli e meno robusti dei granuli anaerobici. Inoltre, la resa in EPS dei granuli di anammox è superiore alla media dei granuli anaerobici ed è caratterizzata da una maggiore quantità di PN e PS. D'altra parte, nei campioni di anammox, è visibile una tendenza negativa da luglio a dicembre del rapporto PN/PS, che potrebbe indicare un malfunzionamento del reattore.Extracellular polymeric substances (EPS) are chains of polysaccharides secreted by bacterial cells. EPS protect bacteria from external factors such as environmental conditions and toxic substances; ensure cell stability; enhance adsorption and adhesion properties; represent a source of carbon and energy. EPS are present in granular sludge both in anaerobic ammonium oxidation (anammox) and anaerobic processes, two broadly adopted wastewater treatment techniques for nitrogen removal. The main objectives are to analyse the differences among anammox granules, to unravel their composition, to compare anammox and anaerobic granules and EPS, and to correlate the performances of the anammox reactor with the EPS quality.
During my work at the laboratory of environmental engineering (laboratorio di ingegneria ambientale – LIA) of the Department of Civil and Environmental Engineering (DICA) of Politecnico di Milano, EPS both from anammox and anaerobic granular sludge have been extracted, analysed and compared. In particular, the work was conducted on five anammox samples and two anaerobic. The anammox were collected monthly from July to December from a pilot-scale reactor of a textile industry located in Como (Lombardy) while anaerobic granules come from two different wastewater treatment plants (WWTP) dealing with effluents from a brewery and a paper industry. First of all, granular sludge has been studied, both quantitively and qualitatively. Secondly, EPS was extracted using the heating-Na2CO3 based method; polysaccharides (PS) and protein (PN) fractions of EPS and its yield have been calculated; UltraViolet-Visible Spectroscopy (UV-vis) and polymeric fraction characterisation were performed.
It was observed that anammox granules are more reddish, smaller and less robust than anaerobic granules. Moreover, the EPS yield of anammox granules is above the anaerobic granules average, and it is characterised by a higher amount of PN and PS. On the other hand, in anammox samples collected from July to December, a decreasing PN/PS trend is visible, which might indicate a reactor malfunctioning
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Hydrogels formed by anammox extracellular polymeric substances: Structural and mechanical insights
Full text linkThe recovery of biopolymers from the waste sludge produced in wastewater treatments and their application in other industrial sectors, would substantially increase the environmental and economical sustainability of the process, promoting the development of a circular economy. In this study, extracellular polymeric substances (EPS) extracted from anammox granular waste sludge, were investigated and characterized. Rheological and differential scanning calorimetry measurements on EPS aqueous dispersions indicate the formation of an extended 3-D network above a threshold concentration, with a clear dependence of the mechanical and water retention properties on EPS content. The structural characterization, performed with transmission electron microscopy and small angle X-ray scattering, reveals the presence of functional amyloids as putative structural units, observed for the first time in an EPS-based hydrogel. As a proof of concept of the applicative potential, we explored the water and grease resistance provided to paper by an EPS coating. These results shed light on the structural details of EPS-based hydrogels, and pave the way for the possible use of EPS-based materials as a cheap, eco-friendly alternative to commonly adopted paper coatings, in line with a circular economy pattern for wastewater treatment
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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