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Rizzato G.,University of Venice | Scalabrin E.,University of Venice | Radaelli M.,University of Venice | Capodaglio G.,University of Venice | Piccolo O.,S.C.S.O.P.
Food Chemistry | Year: 2017

The roots and rhizomes of licorice plants (genus Glycyrrhiza L.) are commercially employed, after processing, in confectionery production or as sweetening and flavouring agents in the food, tobacco and beer industries. G. glabra, G. inflata and G. uralensis are the most significant licorice species, often indistinctly used for different productions. Licorice properties are directly related to its chemical composition, which determines the commercial values and the quality of the derived products. In order to better understand the characteristics and properties of each species, a chemical characterization of three species of licorice (G. glabra, G. inflata, G. uralensis) is proposed, through an untargeted metabolomic approach and using high-resolution mass spectrometry. The statistical analysis reveals new possible markers for the analyzed species, and provides a reliable identification of a high number of metabolites, contributing to the characterization of Glycyrrhiza metabolome. © 2016 Elsevier Ltd


Arcon I.,University of Nova Gorica | Arcon I.,Jozef Stefan Institute | Piccolo O.,SCSOP | Paganelli S.,University of Venice | Baldi F.,University of Venice
BioMetals | Year: 2012

A strain of Klebsiella oxytoca, isolated from acid pyrite-mine drainage, characteristically produces a ferric hydrogel, consisting of branched heptasaccharide repeating units exopolysaccharide (EPS), with metal content of 36 wt%. The high content of iron in the EPS matrix cannot be explained by a simple ferric ion bond to the sugar skeleton. The bio-generated Fe-EPS is investigated by X-ray absorption spectroscopy. Fe K-edge XANES analysis shows that iron is mostly in trivalent form, with a nonnegligible amount of Fe 2+ in the structure. The Fe EXAFS results indicate that iron in the sample is in a mineralized form, prevalently in the form of nanosized particles of iron oxides/hydroxides, most probably a mixture of different nano-crystalline forms. TEM shows that these nanoparticles are located in the interior of the EPS matrix, as in ferritin. The strain produces Fe-EPS to modulate Fe-ions uptake from the cytoplasm to avoid iron toxicity under anaerobic conditions. This microbial material is potentially applicable as iron regulator. © Springer Science+Business Media, LLC. 2012.


Rathod V.D.,University of Venice | Paganelli S.,University of Venice | Piccolo O.,SCSOP
Catalysis Communications | Year: 2016

The use of water as co-solvent for biphasic reactions and of easily recyclable water-soluble catalysts are highly desirable for the realization of greener processes. The selective reduction of halo nitroarenes to the corresponding haloanilines is a very important industrial transformation for the production of agrochemicals, pigments, bactericides and pharmaceuticals and is not easy to obtain. The application of a water soluble catalyst, prepared by rhodium species and a cheap thioligand, in the hydrogenation of some halonitroarenes is here described. Excellent conversions, good recyclability of the catalytic species embedded in the aqueous phase and very high selectivity are demonstrated. © 2016 Elsevier B.V. All rights reserved.


Paganelli S.,University of Venice | Piccolo O.,SCSOP | Pontini P.,University of Venice | Tassini R.,University of Venice | Rathod V.D.,University of Venice
Catalysis Today | Year: 2014

Rh(DHTANa) is a new water-soluble catalyst easily obtained by mixing in water the catalytic precursor [Rh(COD)Cl]2 and the dihydrothioctic acid sodium salt (DHTANa). This catalyst showed to be very active in the hydrogenation of unsaturated substrates as 2-cyclohexen-1-one, the biomass-derived furfural and acetophenone. In this last case the catalytic system obtained by using as water-soluble ligand (R)-(DHTANa) afforded (R)-1-phenylethanol with very modest enantioselectivity. Rh(DHTANa) was active also in the aqueous biphase hydroformylation of styrene producing exclusively the two corresponding aldehydes with 80-86% selectivity toward the branched aldehyde 2-phenylpropanal. This new catalytic system was easily recycled in both hydrogenation and hydroformylation processes and no leaching phenomenon was observed. © 2014 Elsevier B.V. All rights reserved.


Baldi F.,University of Venice | Marchetto D.,University of Venice | Paganelli S.,University of Venice | Piccolo O.,SCSOP
New Biotechnology | Year: 2011

Iron and palladium binding an exopolysaccharide (EPS) were obtained and purified from cultures of bacterial cells of Klebsiella oxytoca BAS-10. The strain BAS-10 was able to grow under anaerobic conditions with Fe(III)-citrate as energy and carbon source, producing Fe(III)-EPS that was extracted and used as catalyst in the oxidation reaction of phenol with H 2O 2. The same bacterial strain was cultivated anaerobically with Na-citrate and Pd 2(NO) 3 was added during the exponential growth to afford a Pd-EPS, named Bio-Pd (A), that, after isolation and purification, was used as catalyst in the reductive dehalogenation of chlorobenzene as model reaction. For comparison other two palladium binding polysaccharides were prepared: (a) a second type Pd-EPS, named Bio-Pd (B), was obtained by an exchange reaction with Pd acetate starting from an iron-free EPS produced by strain BAS-10 growing on Na-citrate medium; (b) a third type of palladium, named Bio-Pd (C), bound to a different polysaccharide, was recovered after the same exchange reaction applied on glycolipid emulsan obtained from an aerobic culture of Acinetobacter venetianus RAG 1. The superiority of Bio-Pd (A), as catalyst, vs Bio-Pd (B) and (C) was demonstrated. This approach to use microorganisms to prepare metal bound polysaccharides is novel and permits to prepare metal species, sequestrated in aqueous phase that can be useful either as catalysts for synthetic applications or to support the microbial biotransformation of pollutants. © 2011 Elsevier B.V.


Paganelli S.,University of Venice | Piccolo O.,SCSOP | Baldi F.,University of Venice | Tassini R.,University of Venice | And 2 more authors.
Applied Catalysis A: General | Year: 2013

A palladium species bound to an exopolysaccharide (Pd-EPS) was obtained from alive bacterial cells of Klebsiella oxytoca BAS-10 grown in static mode in the presence of Pd(NO3)2. Pd-EPS, after isolation and purification, was used as catalyst in the aqueous biphasic hydrogenation either of unfunctionalyzed olefins, as styrene, 1-octene and 1,3-diisopropenylbenzene, or of some α,β-unsaturated aldehydes. The catalytic system was very active under mild reaction conditions and its activity was maintained in some recycle experiments. Even more efficient was the "activated Pd-EPS", obtained by a pre-treatment of Pd-EPS with 1 MPa of H2 at 30 °C for 21 h; while Pd-EPS originally contains only Pd(II), as demonstrated by XPS measurements, the activated catalyst shows the presence of both Pd(II) and Pd(0) in the ratio 1.9/1. The two catalytic systems show different structures at TEM observations evidencing the transformation of electron ultradense nanoaggregates (Pd-EPS) into jagged microaggregates ("activated Pd-EPS"). © 2012 Elsevier B.V.


Giomi D.,University of Florence | Malavolti M.,University of Florence | Piccolo O.,SCSOP | Salvini A.,University of Florence | Brandi A.,University of Florence
RSC Advances | Year: 2014

A new method for the transformation of glycerol into mono- and dichlorohydrins has been studied. With trimethylchlorosilane as chlorinating agent and acetic acid as catalyst, mono- and dichlorohydrins have been obtained in high yields and selectivity. In fact, under different reaction conditions, the synthesis of α-monochlorohydrin (3-chloropropan-1,2-diol) or α,γ-dichlorohydrin (1,3-dichloropropan-2-ol) as predominant product has been achieved. This process was also exploited for the valorisation of the crude mixture of glycerol and monochlorohydrin (glyceric mixture), a by-product from an earlier BioDiesel production. A reaction mechanism has been proposed based on investigations on the chlorination of different alcohols. © 2014 the Partner Organisations.


Tassini R.,University of Venice | Rathod V.D.,University of Venice | Paganelli S.,University of Venice | Balliana E.,University of Venice | Piccolo O.,SCSOP
Journal of Molecular Catalysis A: Chemical | Year: 2016

The objective of this study was to prepare, characterize and test the catalytic properties of iron and gallium salts of Aquivion® PFSA (hereinafter Aquivion-H). The samples were characterized by the determination of metal loading in fresh and used materials, ATR-FTIR, and thermogravimetric analysis (TG-DSC). The salts were screened in Friedel-Crafts acylation of some heterocyclic compounds and compared with some homogeneous and heterogeneous Lewis acids as well as with pure Aquivion-H. These new salts revealed efficient catalytic activity and recyclability. © 2015 Elsevier B.V.


PubMed | University of Palermo, University of Venice, SCSOP and University of Siena
Type: Journal Article | Journal: Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine | Year: 2016

Silver nanoparticles (AgNPs), embedded into a specific exopolysaccharide (EPS), were produced by Klebsiella oxytoca DSM 29614 by adding AgNO3 to the cultures during exponential growth phase. In particular, under aerobic or anaerobic conditions, two types of silver nanoparticles, named AgNPs-EPS(aer) and the AgNPs-EPS(anaer), were produced respectively. The effects on bacterial cells was demonstrated by using Escherichia coli K12 and Kocuria rhizophila ATCC 9341 (ex Micrococcus luteus) as Gram-negative and Gram-positive tester strains, respectively. The best antimicrobial activity was observed for AgNPs-EPS(aer), in terms of minimum inhibitory concentrations and minimum bactericidal concentrations. Observations by transmission electron microscopy showed that the cell morphology of both tester strains changed during the exposition to AgNPs-EPS(aer). In particular, an electron-dense wrapped filament was observed in E. coli cytoplasm after 3 h of AgNPs-EPS(aer) exposition, apparently due to silver accumulation in DNA, and both E. coli and K. rhizophila cells were lysed after 18 h of exposure to AgNPs-EPS(aer). The DNA breakage in E. coli cells was confirmed by the comparison of 3-D fluorescence spectra fingerprints of DNA. Finally the accumulation of silver on DNA of E. coli was confirmed directly by a significant Ag(+) release from DNA, using the scanning electrochemical microscopy and the voltammetric determinations.


PubMed | S.C.S.O.P. and University of Venice
Type: | Journal: Food chemistry | Year: 2016

The roots and rhizomes of licorice plants (genus Glycyrrhiza L.) are commercially employed, after processing, in confectionery production or as sweetening and flavouring agents in the food, tobacco and beer industries. G. glabra, G. inflata and G. uralensis are the most significant licorice species, often indistinctly used for different productions. Licorice properties are directly related to its chemical composition, which determines the commercial values and the quality of the derived products. In order to better understand the characteristics and properties of each species, a chemical characterization of three species of licorice (G. glabra, G. inflata, G. uralensis) is proposed, through an untargeted metabolomic approach and using high-resolution mass spectrometry. The statistical analysis reveals new possible markers for the analyzed species, and provides a reliable identification of a high number of metabolites, contributing to the characterization of Glycyrrhiza metabolome.

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