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Dive into the research topics where Leda Giannuzzi is active.

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Featured researches published by Leda Giannuzzi.


Water Research | 2003

Modeling of chlorine effect on floc forming and filamentous micro-organisms of activated sludges

Alejandro H. Caravelli; Edgardo M Contreras; Leda Giannuzzi; Noemí E. Zaritzky

Chlorination is the most economical, non-specific method to control the excessive growth of filamentous micro-organisms causing bulking in activated sludge systems in the treatment of food industrial wastewaters; it was one of the first methods used to control filamentous bulking and is still widely employed. Considering that chlorination affects both floc-forming and filamentous micro-organisms and leaves undesirable disinfection by-products, it is necessary to define the adequate doses to control bulking, minimizing the effect on floc-forming bacteria. In the present work the effect of biomass concentration and type of micro-organism on chlorine decay kinetics was evaluated; the inactivation of either a filamentous (Sphaerotilus natans) or a floc-forming (Acinetobacter anitratus) micro-organism due to chlorination was also analyzed. For chlorine decay assays, the samples were treated in a batch system with sodium hypochlorite ranging between 9.8 and 56.6 mg Cl(2) (gVSS)(-1). Respirometric assays were used to evaluate the effect of chlorine on micro-organisms respiratory activity; in these cases, sodium hypochlorite doses ranged between 2.5 and 18 mgCl(2) (gVSS)(-1).A model that allowed to predict simultaneously chlorine consumption and respiratory activity decay for both micro-organisms as a function of time was proposed. The model includes three coupled differential equations corresponding to respiratory inhibition, readily organic matter oxidation by chlorine and chlorine decay. The rate of chlorine decay depended on both, type and concentration of the micro-organisms in the system. Chlorine consumption rate due to S. natans was 2-4 times faster than A. anitratus. Using the proposed model initial critical chlorine doses (the lowest initial dose that leads to a total inhibition of the respiratory activity) were calculated for both micro-organisms and values of 11.9 mgCl(2) (gVSS)(-1) for S. natans and 4.5 mgCl(2) (gVSS)(-1) for A. anitratus were obtained. These critical doses indicated that in non flocculated pure cultures, floc-former bacteria A. anitratus was more susceptible to chlorine action than S. natans.


Rapid Communications in Mass Spectrometry | 2015

Seven new microcystin variants discovered from a native Microcystis aeruginosa strain – unambiguous assignment of product ions by tandem mass spectrometry

Yulin Qi; Lorena Rosso; Daniela Sedán; Leda Giannuzzi; Darío Andrinolo; Dietrich A. Volmer

RATIONALE High-resolution mass spectrometry was applied to the study of a Microcystis aeruginosa strain previously reported as a [D-Leu(1)]MC-LR producer. Detailed analysis revealed new microcystin (MC) variants produced from the strain, and seven of these were previously unreported variants. This work shows the importance of mass accuracy for the identification of unknown MCs. METHODS The M. aeruginosa strain was isolated from a bloom sample collected from Argentina and acclimated to lab conditions. The MC variants in the strain were separated by UV/Vis detection-guided high-performance liquid chromatography, and their structures were unambiguous determined by tandem mass spectrometry (MS/MS). RESULTS A simple strategy was developed for quickly locating the low-abundance MC precursors from complex samples. MS/MS anlysis revealed ten MC variants produced from the strain, of which seven have never been reported before. CONCLUSIONS This work shows the interference of isobarics and isomers in the study of unknown MCs, and, therefore, high mass accuracy is important to avoid false assignments. Moreover, the peak list provided here (30-50 fragments unambiguously assigned for ten MCs) can be used as a reference for the discovery of MCs from environmental samples.


Materials Science and Engineering: C | 2015

Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

S. Villarruel; Leda Giannuzzi; Sandra Rivero; Adriana Pinotti

This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer-polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging.


Food Control | 2011

Antimicrobial action and effects on beef quality attributes of a gaseous ozone treatment at refrigeration temperatures

F. Coll Cárdenas; S. Andrés; Leda Giannuzzi; Noemí E. Zaritzky


Water Research | 2000

Growth kinetics of the filamentous microorganism Sphaerotilus natans in a model system of a food industry wastewater

Edgardo M Contreras; Leda Giannuzzi; Noemí E. Zaritzky


Food & Function | 2015

A study of the effect of dietary fiber fractions obtained from artichoke (Cynara cardunculus L. var. scolymus) on the growth of intestinal bacteria associated with health

Eliana N. Fissore; Cinthia Santo Domingo; Lía N. Gerschenson; Leda Giannuzzi


International Journal of Food Science and Technology | 2004

The effect of temperature on microbial growth in apple cubes packed in film and preserved by use of orange juice

Silvina C. Andrés; Leda Giannuzzi; Noemí E. Zaritzky


Lwt - Food Science and Technology | 2002

Quality Parameters of Packaged Refrigerated Apple Cubes in Orange Juice

S.C. Andrés; Leda Giannuzzi; Noemí E. Zaritzky


Water Science and Technology | 2002

Competitive growth kinetics of Sphaerotilus natans and Acinetobacter anitratus

Edgardo M Contreras; Leda Giannuzzi; N.E. Zaritzky


International Journal of Food Science and Technology | 2007

Modelling microbial growth in meat broth with added lactic acid under refrigerated storage

Fernanda C. Cardenas; Leda Giannuzzi; Noemí E. Zaritzky

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Noemí E. Zaritzky

National University of La Plata

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Edgardo M Contreras

National Scientific and Technical Research Council

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Adriana Pinotti

National Scientific and Technical Research Council

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Alejandro H. Caravelli

National Scientific and Technical Research Council

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Cinthia Santo Domingo

National Scientific and Technical Research Council

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Daniela Sedán

National Scientific and Technical Research Council

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Darío Andrinolo

National Scientific and Technical Research Council

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Eliana N. Fissore

National Scientific and Technical Research Council

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