Produzione di bioetanolo da effluenti del settore lattiero-caseario con Kluyveromyces marxianus

Il siero di latte e la scotta sono effluenti provenienti rispettivamente dal processo di trasformazione del latte in formaggio e ricotta. Il siero di latte contiene minerali, lipidi, lattosio e proteine; la scotta contiene principalmente lattosio. Il siero può essere riutilizzato in diversi modi, come l'estrazione di proteine o per l’alimentazione animale, mentre la scotta è considerata solamente un rifiuto. Inoltre, a causa degli ingenti volumi di siero prodotti nel mondo, vengono a crearsi seri problemi ambientali e di smaltimento. Destinazioni alternative di questi effluenti, come le trasformazioni biotecnologiche, possono essere un modo per raggiungere il duplice obiettivo di migliorare il valore aggiunto dei processi agroindustriali e di ridurre il loro impatto ambientale. In questo lavoro sono state studiate le condizioni migliori per produrre bioetanolo dal lattosio del siero e della scotta. Kluyveromyces marxianus è stato scelto come lievito lattosio-fermentante. Sono state effettuate fermentazioni su scala di laboratorio aerobiche e anaerobiche in batch, fermentazioni semicontinue in fase dispersa e con cellule immobilizzate in alginato di calcio,. Diverse temperature sono state testate per migliorare la produzione di etanolo. Le migliori prestazioni, per entrambe le matrici, sono state raggiunte a basse temperature (28°C). Anche le alte temperature sono compatibili con buone rese di etanolo nelle fermentazioni con siero. Ottimi risultati si sono ottenuti anche con la scotta a 37°C e a 28°C. Le fermentazioni semicontinue in fase dispersa danno le migliori produzioni di etanolo, in particolare con la scotta. Invece, l'uso di cellule di lievito intrappolate in alginato di calcio non ha migliorato i risultati di processo. In conclusione, entrambi gli effluenti possono essere considerati adatti per la produzione di etanolo. Le buone rese ottenute dalla scotta permettono di trasformare questo rifiuto in una risorsa.

Vanillin production from ferulic acid with Pseudomonas fluorescens BF13-1p4

Bioconversion of ferulic acid to vanillin represents an attractive opportunity for replacing synthetic vanillin with a bio-based product, that can be label “natural”, according to current food regulations. Ferulic acid is an abundant phenolic compound in cereals processing by-products, such as wheat bran, where it is linked to the cell wall constituents. In this work, the possibility of producing vanillin from ferulic acid released enzymatically from wheat bran was investigated by using resting cells of Pseudomonas fluorescens strain BF13-1p4 carrying an insertional inactivation of vdh gene and ech and fcs BF13 genes on a low copy number plasmid. Process parameters were optimized both for the biomass production phase and the bioconversion phase using food-grade ferulic acid as substrate and the approach of changing one variable while fixing the others at a certain level followed by the response surface methodology (RSM). Under optimized conditions, vanillin up to 8.46 mM (1.4 g/L) was achieved, whereas highest productivity was 0.53 mmoles vanillin L-1 h-1). Cocktails of a number of commercial enzyme (amylases, xylanases, proteases, feruloyl esterases) combined with bran pre-treatment with steam explosion and instant controlled pressure drop technology were then tested for the release of ferulic acid from wheat bran. The highest ferulic acid release was limited to 15-20 % of the ferulic acid occurring in bran, depending on the treatment conditions. Ferulic acid 1 mM in enzymatic hydrolyzates could be bioconverted into vanillin with molar yield (55.1%) and selectivity (68%) comparable to those obtained with food-grade ferulic acid after purification from reducing sugars with a non polar adsorption resin. Further improvement of ferulic acid recovery from wheat bran is however required to make more attractive the production of natural vanillin from this by-product.

Modeling, characterization and microalgal cultivation in an airlift panel photobioreactors.

Microalgae cultures are attracting great attentions in many industrial applications. However, one of the technical challenges is to cut down the capital and operational costs of microalgae production systems, with special difficulty in reactor design and scale-up. The thesis work open with an overview on the microalgae cultures as a possible answer to solve some of the upcoming planet issues and their applications in several fields. After the work offers a general outline on the state of the art of microalgae culture systems, taking a special look to the enclosed photobioreactors (PBRs). The overall objective of this study is to advance the knowledge of PBRs design and lead to innovative large scale processes of microalgae cultivation. An airlift flat panel photobioreactor was designed, modeled and experimentally characterized. The gas holdup, liquid flow velocity and oxygen mass transfer of the reactor were experimentally determined and mathematically modeled, and the performance of the reactor was tested by cultivation of microalgae. The model predicted data correlated well with experimental data, and the high concentration of suspension cell culture could be achieved with controlled conditions. The reactor was inoculated with the algal strain Scenedesmus obliquus sp. first and with Chlorella sp. later and sparged with air. The reactor was operated in batch mode and daily monitored for pH, temperature, and biomass concentration and activity. The productivity of the novel device was determined, suggesting the proposed design can be effectively and economically used in carbon dioxide mitigation technologies and in the production of algal biomass for biofuel and other bioproducts. Those research results favored the possibility of scaling the reactor up into industrial scales based on the models employed, and the potential advantages and disadvantages were discussed for this novel industrial design.

Microbial ecology of biotechnological processes

The investigation of phylogenetic diversity and functionality of complex microbial communities in relation to changes in the environmental conditions represents a major challenge of microbial ecology research. Nowadays, particular attention is paid to microbial communities occurring at environmental sites contaminated by recalcitrant and toxic organic compounds. Extended research has evidenced that such communities evolve some metabolic abilities leading to the partial degradation or complete mineralization of the contaminants. Determination of such biodegradation potential can be the starting point for the development of cost effective biotechnological processes for the bioremediation of contaminated matrices. This work showed how metagenomics-based microbial ecology investigations supported the choice or the development of three different bioremediation strategies. First, PCR-DGGE and PCR-cloning approaches served the molecular characterization of microbial communities enriched through sequential development stages of an aerobic cometabolic process for the treatment of groundwater contaminated by chlorinated aliphatic hydrocarbons inside an immobilized-biomass packed bed bioreactor (PBR). In this case the analyses revealed homogeneous growth and structure of immobilized communities throughout the PBR and the occurrence of dominant microbial phylotypes of the genera Rhodococcus, Comamonas and Acidovorax, which probably drive the biodegradation process. The same molecular approaches were employed to characterize sludge microbial communities selected and enriched during the treatment of municipal wastewater coupled with the production of polyhydroxyalkanoates (PHA). Known PHA-accumulating microorganisms identified were affiliated with the genera Zooglea, Acidovorax and Hydrogenophaga. Finally, the molecular investigation concerned communities of polycyclic aromatic hydrocarbon (PAH) contaminated soil subjected to rhizoremediation with willow roots or fertilization-based treatments. The metabolic ability to biodegrade naphthalene, as a representative model for PAH, was assessed by means of stable isotope probing in combination with high-throughput sequencing analysis. The phylogenetic diversity of microbial populations able to derive carbon from naphthalene was evaluated as a function of the type of treatment.

Bioremediation of PCB-contaminated marine sediments: From identification of indigenous dehalorespirers to enhancement of microbial reductive dechlorination

Marine sediments are the main accumulation reservoir of organic recalcitrant pollutants such as polychlorinated biphenyls (PCBs). In the anoxic conditions typical of these sediments, anaerobic bacteria of the phylum Chloroflexi are able to attack these compounds in a process called microbial reductive dechlorination. Such activity and members of this phylum were detected in PCB-impacted sediments of the Venice Lagoon. The aim of this work was to investigate microbial reductive dechlorination and design bioremediation approaches for marine sediments of the area. Three out of six sediment cultures from different sampling areas exhibited dechlorination activities in the same conditions of the site and two phylotypes (VLD-1 and VLD-2) were detected and correlated to this metabolism. Biostimulation was tested on enriched dechlorinating sediment cultures from the same site using five different electron donors, of which lactate was the best biostimulating agent; complementation of microbial and chemical dechlorination catalyzed by biogenic zerovalent Pd nanoparticles was not effective due to sulfide poisoning of the catalyst. A new biosurfactant-producing strain of Shewanella frigidimarina was concomitantly obtained from hydrocarbon-degrading marine cultures and selected because of the low toxicity of its product. All these findings were then exploited to develop bioremediation lab-scale tests in shaken reactors and static microcosms on real sediments and water of the Venice lagoon, testing i) a bioaugmentation approach, with a selected enriched sediment culture from the same area, ii) a biostimulation approach with lactate as electron donor, iii) a bioavailability enhancement with the supplementation of the newly-discovered biosurfactant, and iv) all possible combinations of the afore-mentioned approaches. The best bioremediation approach resulted to be a combination of bioaugmentation and bioremediation and it could be a starting point to design bioremediation process for actual marine sediments of the Venice Lagoon area.

Sintesi di nuovi copolimeri a struttura controllata per inibire la formazione d'idrati

Durante i processi di estrazione può avvenire la formazione spontanea d’idrati di gas naturali, i quali, agglomerandosi, possono ostruire le tubazioni. Inibire la formazione degli idrati è quindi di fondamentale importanza al fine di prevenire danni ambientali ed economici. In questo contesto abbiamo ritenuto interessante sintetizzare diversi copolimeri a struttura controllata con lo scopo di utilizzarli come inibitori d’idrati. In particolare, dopo aver ottimizzato la sintesi dell’omopolimero costituente il primo blocco mediante ATRP, questo è stato utilizzato come macroiniziatore per la successiva copolimerizzazione di tre altri monomeri a diversa polarità. L’efficienza d’inibizione di tutti i derivati copolimerici ottenuti è stata testata e confrontata con quella di additivi commerciali attualmente in uso mediante DSC.

The missing link between clinical states and biomarkers in mental disorders

Current diagnostic definitions of psychiatric disorders based on collections of symptoms encompass very heterogeneous populations and are thus likely to yield spurious results when exploring biological correlates of mental disturbances. It has been suggested that large studies of biomarkers across diagnostic entities may yield improved clinical information. Such a view is based on the concept of assessment as a collection of symptoms devoid of any clinical judgment and interpretation. Yet, important advances have been made in recent years in clinimetrics, the science of clinical judgment. The current clinical taxonomy in psychiatry, which emphasizes reliability at the cost of clinical validity, does not include effects of comorbid conditions, timing of phenomena, rate of progression of an illness, responses to previous treatments, and other clinical distinctions that demarcate major prognostic and therapeutic differences among patients who otherwise seem to be deceptively similar since they share the same psychiatric diagnosis. Clinimetrics may provide the missing link between clinical states and biomarkers in psychiatry, building pathophysiological bridges from clinical manifestations to their neurobiological counterparts.

Ms. lat. qu. 98 - Vienna liberata

Vorbesitzer: Pietro Ercole Fava

La enseñanza de la pedagogía en la formación de profesores y licenciados en Ciencias de la Educación. La intervención educativa como eje de la propuesta

En este trabajo analizamos la propuesta de enseñanza de la materia Pedagogía II para la formación de profesionales en Ciencias de la Educación de la Universidad Nacional de La Plata. El Plan de Estudios vigente ubica a esta asignatura en el tercer año de la Carrera dentro del trayecto curricular denominado de Formación Básica. En su propuesta de enseñanza se propone una teorización acerca de la educación que se centra en los últimos treinta años de desarrollo de la disciplina al mismo tiempo que reconoce la historicidad como categoría de análisis de discursos y prácticas. Portadora de una intencionalidad cultural y social, conviven en ella interrogantes, problemas y debates que aunque impregnados de incertidumbre, no dejan de ofrecer principios y criterios pedagógicos para pensar en alternativas superadoras. En ese entendimiento, el curso afianza la mirada pedagógica analizando las articulaciones complejas y contradictorias entre educación y sociedad, las principales tendencias pedagógicas actuales, los rasgos que adoptan hoy los distintos tipos de educación en sus diferentes niveles de formalización y la especificidad propia de la disciplina pedagógica. Pero también destaca las posibilidades de la educación como una de las instancias de mejoramiento del ser humano y de la sociedad. Sobre esa base, la de considerar a la pedagogía como una disciplina implicada en la acción, o sea que interpreta el hecho educativo a la vez que se compromete con el quehacer práctico, hemos reorganizado la materia en función de la experiencia adquirida por la cátedra en estos dos últimos años, colocando a la intervención pedagógica como eje de la propuesta. Esta categoría se constituyó para el equipo de cátedra en una fuente reveladora de nuevos análisis por aportar una nueva mirada a la dinámica siempre renovada de la dialéctica teoría práctica y por encontrar en ella una de las de mayor especificidad en las tareas a realizar por el pedagogo. También ha posibilitado que los alumnos reflexionen sobre su rol como pedagogos y vivencien las complejas relaciones entre conocimientos teóricos y prácticas educativas.

La formación pedagógica : Políticas, tendencias y prácticas en la UNLP

Tabla de contenidos: Tendencias pedagógicas en la carrera de ciencias de la educación. La incorporación y el desarrollo de las pedagogías tecnocráticas [1960-1990] / Julia Silber. La antesala de la dictadura. Quiebres con el pasado y continuidades con el régimen militar en el Departamento de Ciencias de la Educación / Julia Silber, Paula Citarella, Maximiliano Fava. Las políticas de normalización autoritaria : Una aproximación a los concursos realizados en la carrera de ciencias de la educación [1980-1983] / Mónica Paso. Grupos académicos y reformas curriculares. El caso del plan de estudios de ciencias de la educación durante el período de la normalización [1983-1986] / Luciana Garatte. Las prácticas de la enseñanza en el curriculum prescripto de la carrera de ciencias de la educación. Análisis de las tendencias pedagógicas [1959-1984] / María Gabriela Hernando. Las prácticas de la enseñanza en la carrera de ciencias de la educación. Los relatos de quienes fueron alumnos [1964-1982] / Marina Barcia. La formación pedagógica en carreras de profesorados en la década de 1960. Entre la filosofía y la ciencia / María Esther Elías, Patricia Belardinelli. Aspectos fundacionales en la formación docente de los profesores de inglés [1969-1985] / Silvana J. Barboni.

La enseñanza de la pedagogía en la formación de profesores y licenciados en Ciencias de la Educación. La intervención educativa como eje de la propuesta

En este trabajo analizamos la propuesta de enseñanza de la materia Pedagogía II para la formación de profesionales en Ciencias de la Educación de la Universidad Nacional de La Plata. El Plan de Estudios vigente ubica a esta asignatura en el tercer año de la Carrera dentro del trayecto curricular denominado de Formación Básica. En su propuesta de enseñanza se propone una teorización acerca de la educación que se centra en los últimos treinta años de desarrollo de la disciplina al mismo tiempo que reconoce la historicidad como categoría de análisis de discursos y prácticas. Portadora de una intencionalidad cultural y social, conviven en ella interrogantes, problemas y debates que aunque impregnados de incertidumbre, no dejan de ofrecer principios y criterios pedagógicos para pensar en alternativas superadoras. En ese entendimiento, el curso afianza la mirada pedagógica analizando las articulaciones complejas y contradictorias entre educación y sociedad, las principales tendencias pedagógicas actuales, los rasgos que adoptan hoy los distintos tipos de educación en sus diferentes niveles de formalización y la especificidad propia de la disciplina pedagógica. Pero también destaca las posibilidades de la educación como una de las instancias de mejoramiento del ser humano y de la sociedad. Sobre esa base, la de considerar a la pedagogía como una disciplina implicada en la acción, o sea que interpreta el hecho educativo a la vez que se compromete con el quehacer práctico, hemos reorganizado la materia en función de la experiencia adquirida por la cátedra en estos dos últimos años, colocando a la intervención pedagógica como eje de la propuesta. Esta categoría se constituyó para el equipo de cátedra en una fuente reveladora de nuevos análisis por aportar una nueva mirada a la dinámica siempre renovada de la dialéctica teoría práctica y por encontrar en ella una de las de mayor especificidad en las tareas a realizar por el pedagogo. También ha posibilitado que los alumnos reflexionen sobre su rol como pedagogos y vivencien las complejas relaciones entre conocimientos teóricos y prácticas educativas.

Bolboforma abundance in ODP Hole 162-982A and DSDP Hole 12-116 sediments

Although they are fossils of uncertain origin, bolboforms are the best calcareous microfossil group for Neogene biostratigraphy in the North Atlantic. Fifty-two Bolboforma species were observed at the Hatton-Rockall Basin in Ocean Drilling Program Holes 982A (26 samples) and 982B (301 samples) and in Deep Sea Drilling Project Hole 116 (71 samples). The sequence investigated spans the interval from lower Miocene to upper Pliocene. Fourteen zones/subzones were identified and correlated with the calcareous nannoplankton zones, the planktonic foraminifer biostratigraphy, and the time (Ma). The last occurrence of the genus Bolboforma can be dated to 2.84 Ma. Different Bolboforma specimens of middle Miocene age, observed in upper Miocene and upper middle Miocene sediments at Site 982, document redeposition of sediment from the Rockall Bank into the Hatton-Rockall Basin during the latest middle Miocene and late Miocene.