Pyrolysis of peptides and proteins. Analytical study and environmental applications

Adamiano, Alessio (2012) Pyrolysis of peptides and proteins. Analytical study and environmental applications, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Scienze ambientali: tutela e gestione delle risorse naturali, 24 Ciclo. DOI 10.6092/unibo/amsdottorato/4671.
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Abstract

Analytical pyrolysis was used to investigate the formation of diketopiperazines (DKPs) which are cyclic dipeptides formed from the thermal degradation of proteins. A quali/quantitative procedure was developed combining microscale flash pyrolysis at 500 °C with gas chromatography-mass spectrometry (GC-MS) of DKPs trapped onto an adsorbent phase. Polar DKPs were silylated prior to GC-MS. Particular attention was paid to the identification of proline (Pro) containing DKPs due to their greater facility of formation. The GC-MS characteristics of more than 80 original and silylated DKPs were collected from the pyrolysis of sixteen linear dipeptides and four model proteins (e.g. bovine serum albumin, BSA). The structure of a novel DKP, cyclo(pyroglutamic-Pro) was established by NMR and ESI-MS analysis, while the structures of other novel DKPs remained tentative. DKPs resulted rather specific markers of amino acid sequence in proteins, even though the thermal degradation of DKPs should be taken into account. Structural information of DKPs gathered from the pyrolysis of model compounds was employed to the identification of these compounds in the pyrolysate of proteinaceous samples, including intrinsecally unfolded protein (IUP). Analysis of the liquid fraction (bio-oil) obtained from the pyrolysis of microalgae Nannochloropsis gaditana, Scenedesmus spp with a bench scale reactor showed that DKPs constituted an important pool of nitrogen-containing compounds. Conversely, the level of DKPs was rather low in the bio-oil of Botryococcus braunii. The developed micropyrolysis procedure was applied in combination with thermogravimetry (TGA) and infrared spectroscopy (FT-IR) to investigate surface interaction between BSA and synthetic chrysotile. The results showed that the thermal behavior of BSA (e.g. DKPs formation) was affected by the different form of doped synthetic chrysotile. The typical DKPs evolved from collagen were quantified in the pyrolysates of archaeological bones from Vicenne Necropolis in order to evaluate their conservation status in combination with TGA, FTIR and XRD analysis.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Adamiano, Alessio
Supervisore
Dottorato di ricerca
Scuola di dottorato
Scienze della terra e dell'ambiente
Ciclo
24
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
Analytical chemistry; Pyrolysis/Gas Chromatography; Bench scale pyrolysis; GC-MS method; Protein thermal degradation; Cyclodipeptide; DKP; Piperazinedione; Proline containing dipeptide; Bovine serum albumin; Collagen; Lysozyme; Ovalbumin; Biomass; Microalgae; Bio-oil; Biofuel; Chrysotile; Nanoparticle; Nanofiber; Protein interaction with solid surface; Vicenne Necropolis; Archaeological bone; Intrinsically unfolded protein; Haliotis rufescens;
URN:NBN
DOI
10.6092/unibo/amsdottorato/4671
Data di discussione
14 Maggio 2012
URI

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