117,382 research outputs found
Designing Novel Sustainable Biorefinery Models
No full textIn un’epoca segnata dal riscaldamento globale e dall’instabilità climatica, diventa urgente il passaggio da metodologie produttive fossili a strategie basate su un’economia circolare. La tesi affronta questo tema evidenziando approcci biorefineristici per la valorizzazione di sottoprodotti ad alto valore nutrizionale e potenzialmente dannosi se smaltiti impropriamente: gli oli esausti da cucina (WCO) e il siero del latte (CW).
Nel secondo capitolo, tramite l’ottimizzazione delle condizioni fermentative, è stato indagato l’uso del lievito non convenzionale Yarrowia lipolytica (ceppo W29) per produrre lipasi extracellulari e accumulare oli cellulari singoli (SCO) impiegando WCO come fonte di carbonio. Gli esperimenti, effettuati variando le concentrazioni di WCO e glucosio e diverse condizioni di pH, hanno evidenziato che anche elevate concentrazioni di WCO (100–200 g/l) favoriscono una significativa attività lipasica (fino a circa 1 U/ml) e una crescente accumulazione di SCO, correlata alla disponibilità di acidi grassi liberi.
Il terzo capitolo esplora l’utilizzo del lattosio derivato dal CW in fermentazioni condotte con il lievito Kluyveromyces marxianus DSM 7239 per produrre etanolo, variando temperature (30° e 37°C) e concentrazioni (100–200 g/l). I dati sperimentali hanno permesso di sviluppare un modello di simulazione per un impianto industriale in Puglia (539 m3/giorno di CW) articolato in tre sezioni: pretrattamento con filtrazione a membrana (per ottenere un concentrato proteico e acqua riutilizzabile), fermentazione-distillazione per etanolo anidro, e trattamento delle acque reflue tramite digestione anaerobica con cogenerazione. L’analisi tecnico-economica ha identificato uno scenario ottimale (YE/L = 0.45 g/g, prezzo minimo di 1.43 €/kg) ed evidenziato la sensibilità del modello al prezzo del CW, sottolineando l’importanza di politiche statali di sostegno come possibili prezzi al cancello associati allo smaltimento del CW.
Il quarto capitolo conclude la tesi con considerazioni finali e una revisione sistematica della letteratura (metodologia PRISMA) sull’applicazione del Life Cycle Assessment (LCA) alla valorizzazione del CW, rivelando come quest’ultimo venga spesso trattato solo come sottoprodotto, nonostante il suo potenziale, mentre la produzione di latte risulta il principale “hotspot” ambientale.In an era marked by global warming and climate instability, shifting from fossil-based production to a circular economy is imperative. This thesis addresses two biorefinery approaches for valorizing nutrient-rich waste streams that can pose environmental risks if mismanaged: waste cooking oils (WCO) and cheese whey (CW).
Chapter 2 investigates the optimization of fermentation conditions using the unconventional yeast Yarrowia lipolytica (strain W29) to produce extracellular lipases and accumulate single-cell oils (SCO) from WCO as a carbon source. Experiments varying WCO and glucose concentrations along with different pH levels demonstrated that even high WCO concentrations (100–200 g/l) enhance lipase activity (up to nearly 1 U/ml) and boost SCO accumulation, due to increased free fatty acid availability.
Chapter 3 examines the fermentation of CW-derived lactose with Kluyveromyces marxianus DSM 7239 to produce ethanol under varying temperatures (30° and 37°C) and substrate concentrations (100–200 g/l). The experimental data were used to model an industrial plant in Apulia processing 539 m3/day of CW, divided into three sections: membrane filtration (yielding whey protein concentrate and reusable water), fermentation-distillation for anhydrous ethanol, and wastewater treatment via anaerobic digestion with cogeneration. Technoeconomic analysis identified an optimal scenario (YE/L = 0.45 g/g, minimum ethanol price 1.43 €/kg), while sensitivity analysis highlighted the model’s reliance on state mandated policies, such as a gate-fee price associated with CW handling.
Chapter 4 concludes with final remarks and a systematic literature review using the PRISMA methodology on LCA applications for CW valorization, showing that CW is often regarded merely as a by-product despite its potential, with milk production emerging as the main environmental hotspot
Mimicking Natural Metabolisms: Cell‐Free Flow Preparation of Dopamine
No full textThe biosynthesis of dopamine (DA) from L-tyrosine as starting material is an excellent yet challenging strategy. Here we developed a versatile, multi-enzymatic platform for the biocatalytic preparation of DA in a continuous mode with excellent conversion (90 %) and reaction time (45 min). The system exploits the immobilization of a decarboxylase from Bacillus pumilis (Fdc) and a tyrosinase from Agaricus bisporus (Tyr), which were combined to mimic the in-vivo synthesis of DA (both primary and secondary metabolisms) giving rise to an efficient strategy with a considerable reduction of process associated costs and environmental impact. To enhance the system automation, an in-line purification via catch-and-release procedure was added
Il podcasting georeferenziato: ambienti multimediali per la comunicazione e la formazione
No full textValorization of Apple Pomace: bacterial cellulose-immobilized β-Glycosidase allows efficient production of phloretin
No full textFood industries produce around 4 million metric tons every year of apple pomace, a mixture of residues and byproducts from apple processing. A high abundance of valuable phenolic compounds is still present in apple residues, though representing a cheap natural source of bioactive molecules for many industrial applications.
Among these compounds, phloretin (PHL) is drawing particular attention for its biological properties. However, due to its small amount present in the biomass with respect to its glycoside, phloridzin (PHZ), the latter is used as starting material of choice. Our group used apple waste to grow Komagataeibacter xylinus DSM2325, an acetic acid bacteria, able to produce high quantity of bacterial cellulose (BC).
By simple chemical modifications, we turned it into a promising support for enzymatic immobilization of extremophilic β-glycosidase AheGH174. Using imm-AHeGH1 in a biphasic systems (HEPES buffer:TMO 50:50, 20 mg/mL imm-AHeGH1, 2 mg/gmatrix enzyme loading, 5 g/L phloridzin) complete de-glycosylation is observed after 7 h of reaction.
While the enzyme immobilization onto BC cellulose pellicles allowed for high catalyst stabilization and reuse (>7 cycles), the employment of the unconventional green solvent TMO dramatically facilitated the isolation of the desired product (i.e., 95% of yield), leaving the sugar moieties in the water phase for their potential reutilization
Apple Pomace valorization: bacterial cellulose-immobilized β-Glycosidase allows efficient production of phloretin
No full textFood industries produce around 4 million metric tons every year of apple pomace, a mixture of residues and byproducts from apple processing. A high abundance of valuable phenolic compounds is still present in apple residues, though representing a cheap natural source of bioactive molecules for many industrial applications. Among these compounds, phloretin (PHL) is drawing particular attention for its biological properties. However, due to its small amount present in the biomass with respect to its glycoside, phloridzin (PHZ), the latter is used as starting material of choice. Our group used apple waste to grow Komagataeibacter xylinus DSM2325, an acetic acid bacterium, able to produce high quantity of bacterial cellulose (BC).
By simple chemical modifications, we turned it into a promising support for enzymatic immobilization of extremophilic β-glycosidase AHeGH1. Using imm-AHeGH1 in a biphasic systems (HEPES buffer:TMO 50:50, 20 mg/mL imm-AHeGH1, 2 mg/gmatrix enzyme loading, 5 g/L PHZ) complete de-glycosylation is observed after 7 h of reaction. While the enzyme immobilization onto BC cellulose pellicles allowed for high catalyst stabilization and reuse (>7 cycles), the employment of the unconventional green solvent TMO dramatically facilitated the isolation of the desired product (i.e., 95% of yield), leaving the sugar moieties in the water phase for their potential reutilization
Association between natremia and respiratory function and symptoms in dust-exposed workers
No full textThe association between natremia and respiratory function and symptoms in a large group of dust-exposed male workers is reporte
Plasma levels of coenzyme Q10, vitamin E and lipids in uremic patients on conservative therapy and hemodialysis treatment: Some possible biochemical and clinical implications
No full textCoenzyme Q(10) (CoQ(10)), vitamin E, total cholesterol, HDL-cholesterol (HDLC) and triglycerides were measured in the plasma of 62 patients with kidney failure, 46 under hemodialysis treatment and 16 under conservative therapy, and 95 controls. The sum of LDL-cholesterol (LDL-C) and VLDL-cholesterol (VLDL-C) was also calculated for each patient. The ratio CoQ(10)/LDL-C+VLDL-C in both conservative therapy and hemodialysis populations was significantly lower (P<0.001) compared with normal controls and remained unchanged after the dialysis treatment. On the contrary the ratio vitamin E/LDL-C+VLDL-C was normal but decreased significantly (P<0.02) after each dialysis. Since coenzyme Q is the main inhibitor of the prooxidant action of vitamin E, it was hypothesized that its decrease in both the populations examined could make the lipoproteins of these patients more vulnerable to a peroxidative attack
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Clinical and functional correlates of the serum level of coenzyme Q and vitamin E in dust-exposed workers
No full textWe found that the serum levels of coenzyme Q and vitamin E were positively correlated with clinical and functional respiratory correlates in dust-exposed workers
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
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