Letteratura scientifica selezionata sul tema "PET hydrolysate"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Consulta la lista di attuali articoli, libri, tesi, atti di convegni e altre fonti scientifiche attinenti al tema "PET hydrolysate".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Articoli di riviste sul tema "PET hydrolysate":
1
Kim, Jae Hwan, Eun Young Jung, Yang Hee Hong, Song Hwan Bae, Jin Man Kim, Dong Ouk Noh, Tsutomu Nozaki, Toshitada Inoue e Hyung Joo Suh. "Short Communication: Pet foods with yeast hydrolysate can reduce body weight and increase girth in beagle dogs". Canadian Journal of Animal Science 92, n. 2 (giugno 2012): 207–10. http://dx.doi.org/10.4141/cjas2011-123.
Abstract (sommario):
Kim, J. H., Jung, E. Y., Hong, Y. H., Bae, S. H., Kim, J. M., Noh, D. O., Nozaki, T., Inoue, T. and Suh, H. J. 2012. Short Communication: Pet foods with yeast hydrolysate can reduce body weight and increase girth in beagle dogs. Can. J. Anim. Sci. 92: 207–210. Beagle dogs fed pet foods that included yeast hydrolysate (YH) were used in the present study to assess the possible use of YH as a functional anti-obesity ingredient in pet food. The change in weight and girth in the YH groups was significantly (P<0.05) lower than that in the control. Plasma malondialdehyde was significantly (P<0.05) lower in the YH groups compared with that in the control. Plasma levels of the reduced form of glutathione were significantly (P<0.05) higher in the YH groups than those in the control. Therefore, YH could be recommended as an anti-obesity functional feed source for dogs.
2
Khir Anuar, Muhammad Afiq, Nur Husna Haron Narashid, Madihah Md Salleh e Adibah Yahya. "Conversion of chicken viscera into protein hydrolysate for palatant production". Malaysian Journal of Fundamental and Applied Sciences 13, n. 4 (26 dicembre 2017): 606–11. http://dx.doi.org/10.11113/mjfas.v0n0.615.
Abstract (sommario):
Flavor and aroma cannot be separated in food industries. The manipulation of the ingredients to increase the taste has started since early civilization. Common example of the earliest application of ingredients to increase the savory taste of the food is soy sauce production. The process of digging out the aroma and flavor includes frying, stewing, grilling as well as fermenting. Nowadays, much complex savory system in food can be achieved through several processes such as Maillard reaction and protein hydrolysate production. The food produced will not only be tasty but healthy. This concept was first focusing on human food production. However, the increasing number of pet owner for about 10% annually since 2008 as reported by US Pet Owner Society demands the same concept to be implemented in pet food industries. Since most pet owners considered their pets as part of their family, the pet food source from 4D (dead, dying, disable and diseased) animals are unacceptable. Therefore, the pet food industries are competing with human food industries to get the clean source of meat for food as well for flavor production. An alternative to overcome this is by utilizing the viscera of the slaughtered chicken for palatant or flavor production. Aside from meat, bones and feathers, viscera are also abundantly being considered as waste and were not fully utilized. They are rich in protein. The protein can be recovered using suitable process and later turned into a value-added product such as flavor. There is a study available for converting the protein waste into protein hydrolysate via chemical and physical technique. However, only few reports are available for the conversion process via indigenous microbes and enzymes. It is believed that the indigenous microbes and enzymes (protease, peptinase) can be utilized for protein hydrolysate production which will later can be utilized as palatant. The palatant produced should have Sulphur-based aroma compound such as 2-methyl-3-furanthiol and 2-furfuryl-thiol which serve as precursors for chicken aroma.
3
Theysgeur, Sandy, Benoit Cudennec, Barbara Deracinois, Claire Perrin, Isabelle Guiller, Anne Lepoudère, Christophe Flahaut e Rozenn Ravallec. "New Bioactive Peptides Identified from a Tilapia Byproduct Hydrolysate Exerting Effects on DPP-IV Activity and Intestinal Hormones Regulation after Canine Gastrointestinal Simulated Digestion". Molecules 26, n. 1 (30 dicembre 2020): 136. http://dx.doi.org/10.3390/molecules26010136.
Abstract (sommario):
Like their owners, dogs and cats are more and more affected by overweight and obesity-related problems and interest in functional pet foods is growing sharply. Through numerous studies, fish protein hydrolysates have proved their worth to prevent and manage obesity-related comorbidities like diabetes. In this work, a human in vitro static simulated gastrointestinal digestion model was adapted to the dog which allowed us to demonstrate the promising effects of a tilapia byproduct hydrolysate on the regulation of food intake and glucose metabolism. Promising effects on intestinal hormones secretion and dipeptidyl peptidase IV (DPP-IV) inhibitory activity were evidenced. We identify new bioactive peptides able to stimulate cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1) secretions, and to inhibit the DPP-IV activity after a transport study through a Caco-2 cell monolayer.
4
Liu, Pan, Yi Zheng, Yingbo Yuan, Tong Zhang, Qingbin Li, Quanfeng Liang, Tianyuan Su e Qingsheng Qi. "Valorization of Polyethylene Terephthalate to Muconic Acid by Engineering Pseudomonas Putida". International Journal of Molecular Sciences 23, n. 19 (20 settembre 2022): 10997. http://dx.doi.org/10.3390/ijms231910997.
Abstract (sommario):
Plastic waste is rapidly accumulating in the environment and becoming a huge global challenge. Many studies have highlighted the role of microbial metabolic engineering for the valorization of polyethylene terephthalate (PET) waste. In this study, we proposed a new conceptual scheme for upcycling of PET. We constructed a multifunctional Pseudomonas putida KT2440 to simultaneously secrete PET hydrolase LCC, a leaf-branch compost cutinase, and synthesize muconic acid (MA) using the PET hydrolysate. The final product MA and extracellular LCC can be separated from the supernatant of the culture by ultrafiltration, and the latter was used for the next round of PET hydrolysis. A total of 0.50 g MA was produced from 1 g PET in each cycle of the whole biological processes, reaching 68% of the theoretical conversion. This new conceptual scheme for the valorization of PET waste should have advantages over existing PET upcycling schemes and provides new ideas for the utilization of other macromolecular resources that are difficult to decompose, such as lignin.
5
Ratnayani, Ketut, Indriani Wisnu Susanto Panjaitan e Ni Made Puspawati. "SCREENING POTENTIAL ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF PROTEIN HYDROLYSATES DERIVED FROM GERMINATED LABLAB BEAN, PIGEON PEA AND KIDNEY BEAN". Journal of Health Sciences and Medicine 1, n. 1 (1 febbraio 2017): 24. http://dx.doi.org/10.24843/jhsm.2017.v01.i01.p07.
Abstract (sommario):
Abstract Protein hydrolysate contains a mixture of various lengths of short peptides chain and free amino acids that may
excert biological activities. This research aims to screen potential antioxidant and antibacterial activities of protein hydrolysate
produced from three kinds of germinated beans i.e. lablab bean (Lablab purpureus), pigeon pea (Cajanus cajan (L.) Millsp) and
kidney bean (Phaseolus vulgaris) through enzymatic hydrolysis process. The steps of research included germination process of
the beans prior to total protein isolation, enzymatic hydrolysis of total protein isolates using pancreatin enzyme, evaluation of
in vitro antioxidant activity of the hydrolysates protein using DPPH (1,1-diphenyl-2-picryl hydrazyl) method, and antibaterial
activity testing towards Eschericia coli and Staphyllococcus aureus bacteria. The results revealed that pancreatine enzyme was
able to hydrolyse germinated protein of lablab bean, pigeon pea and kidney bean at the experiment condition applied with
degree of hydrolysis 34.12%, 27.44%, and 30,93% respectively. It was also found that protein hydrolysates of lablab bean,
pigeon pea, and kidney bean demonstrated antioxidant activity which percentage radical DPPH scavenging activity of 84.02%,
68.97% and 67.89 %. On the other hand, all of those protein hydrolysates did not show any antibacterial activity towards
Eschericia coli and Staphyllococcus aureus bacteria.
6
Bi, Changhao, Xueli Zhang, Lonnie O. Ingram e James F. Preston. "Genetic Engineering of Enterobacter asburiae Strain JDR-1 for Efficient Production of Ethanol from Hemicellulose Hydrolysates". Applied and Environmental Microbiology 75, n. 18 (17 luglio 2009): 5743–49. http://dx.doi.org/10.1128/aem.01180-09.
Abstract (sommario):
ABSTRACT Dilute acid pretreatment is an established method for hydrolyzing the methylglucuronoxylans of hemicellulose to release fermentable xylose. In addition to xylose, this process releases the aldouronate methylglucuronoxylose, which cannot be metabolized by current ethanologenic biocatalysts. Enterobacter asburiae JDR-1, isolated from colonized wood, was found to efficiently ferment both methylglucuronoxylose and xylose in acid hydrolysates of sweet gum xylan, producing predominantly ethanol and acetate. Transformation of E. asburiae JDR-1 with pLOI555 or pLOI297, each containing the PET operon containing pyruvate decarboxylase (pdc) and alcohol dehydrogenase B (adhB) genes derived from Zymomonas mobilis, replaced mixed-acid fermentation with homoethanol fermentation. Deletion of the pyruvate formate lyase (pflB) gene further increased the ethanol yield, resulting in a stable E. asburiae E1(pLOI555) strain that efficiently utilized both xylose and methylglucuronoxylose in dilute acid hydrolysates of sweet gum xylan. Ethanol was produced from xylan hydrolysate by E. asburiae E1(pLOI555) with a yield that was 99% of the theoretical maximum yield and at a rate of 0.11 g ethanol/g (dry weight) cells/h, which was 1.57 times the yield and 1.48 times the rate obtained with the ethanologenic strain Escherichia coli KO11. This engineered derivative of E. asburiae JDR-1 that is able to ferment the predominant hexoses and pentoses derived from both hemicellulose and cellulose fractions is a promising subject for development as an ethanologenic biocatalyst for production of fuels and chemicals from agricultural residues and energy crops.
7
Deb-Choudhury, Santanu, Emma N. Bermingham, Wayne Young, Matthew P. G. Barnett, Scott O. Knowles, Duane Harland, Stefan Clerens e Jolon M. Dyer. "The effects of a wool hydrolysate on short-chain fatty acid production and fecal microbial composition in the domestic cat (Felis catus)". Food & Function 9, n. 8 (2018): 4107–21. http://dx.doi.org/10.1039/c7fo02004j.
8
Castelvetro, Valter, Andrea Corti, Jacopo La Nasa, Francesca Modugno, Alessio Ceccarini, Stefania Giannarelli, Virginia Vinciguerra e Monica Bertoldo. "Polymer Identification and Specific Analysis (PISA) of Microplastic Total Mass in Sediments of the Protected Marine Area of the Meloria Shoals". Polymers 13, n. 5 (5 marzo 2021): 796. http://dx.doi.org/10.3390/polym13050796.
Abstract (sommario):
Microplastics (MPs) quantification in benthic marine sediments is typically performed by time-consuming and moderately accurate mechanical separation and microscopy detection. In this paper, we describe the results of our innovative Polymer Identification and Specific Analysis (PISA) of microplastic total mass, previously tested on either less complex sandy beach sediment or less demanding (because of the high MPs content) wastewater treatment plant sludges, applied to the analysis of benthic sediments from a sublittoral area north-west of Leghorn (Tuscany, Italy). Samples were collected from two shallow sites characterized by coarse debris in a mixed seabed of Posidonia oceanica, and by a very fine silty-organogenic sediment, respectively. After sieving at <2 mm the sediment was sequentially extracted with selective organic solvents and the two polymer classes polystyrene (PS) and polyolefins (PE and PP) were quantified by pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS). A contamination in the 8–65 ppm range by PS could be accurately detected. Acid hydrolysis on the extracted residue to achieve total depolymerization of all natural and synthetic polyamides, tagging of all aminated species in the hydrolysate with a fluorophore, and reversed-phase high performance liquid chromatography (HPLC) (RP-HPLC) analysis, allowed the quantification within the 137–1523 ppm range of the individual mass of contaminating nylon 6 and nylon 6,6, based on the detected amounts of the respective monomeric amines 6-aminohexanoic acid (AHA) and hexamethylenediamine (HMDA). Finally, alkaline hydrolysis of the residue from acid hydrolysis followed by RP-HPLC analysis of the purified hydrolysate showed contamination by polyethylene terephthalate (PET) in the 12.1–2.7 ppm range, based on the content of its comonomer, terephthalic acid.
9
Awosika, Temitola, e Rotimi E. Aluko. "Enzymatic Pea Protein Hydrolysates Are Active Trypsin and Chymotrypsin Inhibitors". Foods 8, n. 6 (10 giugno 2019): 200. http://dx.doi.org/10.3390/foods8060200.
Abstract (sommario):
In this work, we report the potency of enzymatic hydrolysates of pea proteins against trypsin and chymotrypsin. Pea protein concentrate was digested with each of alcalase, chymotrypsin, pepsin, and trypsin, followed by membrane separation of the protein hydrolysates into peptide fractions (<1, 1–3, 3–5, and 5–10 kDa). Peptide size profiling with size-exclusion gel chromatography indicated the narrowest size range (0.85–4.98 kDa) for alcalase. Trypsin activity was strongly (p < 0.05) inhibited by the ultrafiltration fractions (mean IC50 = 2.2 mg/mL) obtained from the trypsin hydrolysate when compared to the unfractionated hydrolysate (IC50 = 6.8 mg/mL). Similarly, ultrafiltration also enhanced trypsin inhibition by the alcalase-digested peptides with an IC50 of 21.4 mg/mL for the unfractionated hydrolysate in comparison to 3.1–4.7 mg/mL for the fractions. However, ultrafiltration did not enhance trypsin inhibitory activity of chymotrypsin-digested peptides, while the peptide separation reduced efficacy of pepsin-digested peptides. In contrast, chymotrypsin inhibition by all the enzymatic digests was significantly (p < 0.05) enhanced by ultrafiltration, especially peptide sizes >3 kDa. Kinetics of enzyme inhibition indicate peptides were bound to the enzyme active site in a competitive mode that led to reduced catalysis. We conclude that the pea peptides could function as useful tools to promote human health and as a preservative during food processing and storage.
10
Sun, Kekui, Zhaoqi Dai, Wenlong Hong, Jianying Zhao, Hang Zhao, Ji Luo e Guangjie Xie. "Effects of Maillard Reaction on Volatile Compounds and Antioxidant Capacity of Cat Food Attractant". Molecules 27, n. 21 (25 ottobre 2022): 7239. http://dx.doi.org/10.3390/molecules27217239.
Abstract (sommario):
In this study, self-made cat food attractant was prepared by Maillard reaction using hydrolysate of grass carp waste as raw material and glucose and cysteine hydrochloride as substrate. Its volatile compounds, antioxidant capacity, and pet palatability were investigated. The volatile compounds of attractants were analyzed using gas chromatography–mass spectrometry (GC-MS) which showed that alcohols and aldehydes were the most volatile in self-made attractants, accounting for 34.29% and 33.52%, respectively. Furthermore, Maillard reaction could significantly increase the antioxidant activity of self-made attractant, including scavenging activity on OH and DPPH free radicals as well as the chelating ability of Fe2+. The acceptance and palatability of two kinds of cat food were studied by adding 3% self-made or commercial attractants. The results of this study also found that both attractants could remarkably improve the intake rate of cat food. However, the self-made group was significantly less than the commercial group in first smell, first bite, and feeding rate, which might be because of the absence of umami ingredients and spices in self-made attractants.
Tesi sul tema "PET hydrolysate":
1
Kilaparthi, Sravan Kumar. "Carbon-based electrocatalysts for CO2 reduction, PET hydrolysate, and water splitting towards value-added products". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN051.
Abstract (sommario):
Cette étude aborde les principaux défis mondiaux tels que les émissions de CO2, la crise énergétique et la mauvaise gestion des déchets plastiques PET, qui non seulement polluent l'environnement mais contribuent également aux émissions de CO2 lors de l'incinération. L'approche innovante présentée dans cette thèse offre une double solution, abordant simultanément les déchets PET et les émissions de CO2.Deux systèmes remarquables ont été explorés dans cette thèse. Le premier utilisait du carbonate d'oxyde de bismuth (BOC) fonctionnalisé de l'oxyde de graphène réduit (rGO) pour l'électroréduction cathodique du CO2 (CO2RR), tandis que CuCoO sur rGO était utilisé pour l'oxydation anodique de l'hydrolysat de PET. De manière impressionnante, le catalyseur anodique CuCoO@rGO a affiché une électroactivité exceptionnelle, atteignant un rendement faradique (FE) exceptionnel de 85,7 % à 1,5 V par rapport à RHE. Simultanément, le catalyseur cathodique BOC@rGO a démontré un FE impressionnant de 97,4 % à -0,8 V par rapport au RHE, facilitant la production de formiate à partir de CO2RR. Lorsqu'elle est intégrée dans une configuration d'électrolyseur, cette approche a abouti à une production d'acide formique à une faible tension de cellule de 1,9 V et à un FE formiate remarquable de 151,8 % à 10 mA cm-2.Un autre système utilisait une électrode 3D en feutre de charbon actif (aCF) comme substrat et du bismuth a été déposé électrochimiquement sur le CF (Bi@aCF) qui agit comme la cathode CO2RR et un feutre de carbone déposé au phosphate de nickel-cobalt (NiCoPOx@CF) pour l'anode. Procédé d'oxydation de l'hydrolysat de PET. Cette configuration a atteint un FE élevé de 94 % pendant CO2RR à -0,8 V par rapport au RHE, produisant du formiate, et un FE de 95 % pour l'oxydation anodique de l'hydrolysat de PET pour former un formiate à un faible potentiel de 1,5 V par rapport au RHE. Remarquablement, l'électrolyseur à deux électrodes a atteint un FE extraordinaire de 157 % pour produire du formiate à une tension de cellule de 1,8 V. Cette percée représente une nouvelle voie pour valoriser les déchets de PET, réduire les émissions de CO2 et promouvoir la durabilité environnementale.De plus, nos expériences ont également porté sur l'électrolyse de l'eau, où une nouvelle stratégie impliquant du Ru intégré dans une matrice de nitrure de carbone a été proposée. Cette approche, utilisant une structure organique covalente 2D CIN-1 avec Ru + 2 coordonné, a abouti à des nanoparticules d'oxyde de Ru avec des sites Ru de faible valence disposés en nanofils entre des couches de nitrure de carbone graphitique après pyrolyse. Ce matériau présentait des surpotentiels significativement inférieurs pour la réaction de dégagement d'hydrogène (HER) et la réaction de dégagement d'oxygène (OER) par rapport aux catalyseurs de référence au Pt et au RuO2, démontrant une stabilité catalytique remarquable. Cette découverte est extrêmement prometteuse pour faire progresser le domaine du fractionnement de l'eau et contribuer au développement de solutions énergétiques durablesThis study tackles the major global challenges such as CO2 emissions, energy crisis and PET plastic waste mismanagement, which not only pollutes the environment but also contributes to CO2 emissions during incineration. The innovative approach presented in this thesis offers a dual solution, addressing both PET waste and CO2 emissions simultaneously.Two remarkable systems have been explored in this thesis. The first utilized Bismuth oxide carbonate (BOC) functionalized reduced graphene oxide (rGO) for cathodic CO2 electroreduction (CO2RR), while CuCoO on rGO was employed for anodic PET hydrolysate oxidation. Impressively, the anodic CuCoO@rGO catalyst displayed exceptional electro-activity, achieving an outstanding Faradaic efficiency (FE) of 85.7% at 1.5V vs. RHE. Simultaneously, the cathodic BOC@rGO catalyst demonstrated an impressive FE of 97.4% at -0.8 V vs. RHE, facilitating the production of formate from CO2RR. When integrated into an electrolyzer setup, this approach resulted in formic acid production at a low cell voltage of 1.9 V and a remarkable formate FE of 151.8% at 10 mA cm-2.Another system employed a 3D activated carbon felt (aCF) electrode as substrate and Bismuth has been deposited electrochemically on the CF (Bi@aCF) which acts as the cathode CO2RR and nickel cobalt phosphate-deposited carbon felt (NiCoPOx@CF) for the anodic PET hydrolysate oxidation process. This setup achieved a high FE of 94% during CO2RR at -0.8 V vs. RHE, producing formate, and a FE of 95% for anodic PET hydrolysate oxidation to formate at a low potential of 1.5 V vs. RHE. Remarkably, the two-electrode electrolyzer attained an extraordinary FE of 157% to produce formate at a cell voltage of 1.8 V. This breakthrough represents a novel pathway for upcycling PET waste, reducing CO2 emissions, and promoting environmental sustainability.Additionally, our experiments also delved into water electrolysis, where a novel strategy involving Ru embedded in a carbon nitride matrix was proposed. This approach, utilizing a covalent organic framework 2D CIN-1 structure with coordinated Ru+2, resulted in Ru oxide nanoparticles with low-valence Ru sites arranged in nanowires between layers of graphitic carbon nitride after pyrolysis. This material exhibited significantly lower overpotentials for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to benchmark Pt and RuO2 catalysts, demonstrating remarkable catalytic stability. This discovery holds tremendous promise for advancing the field of water splitting and contributing to the development of sustainable energy solutions
2
Billig, Susan. "Abbau von Polyethylenterephthalat mit PET-Hydrolasen aus Thermobifida fusca KW3". Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-85714.
Abstract (sommario):
Der Actinomycet T. fusca KW3, isoliert aus Kompost, bildete während der Kultivierung im Mineralsalz-Spurenelement-Vitamin-Minimalmedium nach Zusatz von PET-Fasern eine 52 kDa Carboxylesterase (TfCa), welche effizient zyklische PET Trimere (CTR) hydrolysiert. Die TfCa besitzt einen pI von 4,8, eine Substratspezifität gegenüber kurzkettigen p-Nitrophenyl-Estern und wird durch Phenylmethylsulfonylfluorid (PMSF) und Tosyl-L-Phenylalanin-Chloromethylketon (TPCK) in der Aktivität gehemmt. Die Carboxylesterase hydrolysiert kein Cutin oder Poly-ε-caprolacton (PCL). CTR hingegen wurden durch die TfCa mit einem Km von 0,5 mM und einer Vmax von 9,3 μmol/min/mg bei optimalen Bedingungen (60°C, pH 6) hydrolysiert. Das aktive Zentrum der Carboxylesterase besteht aus den Aminosäuren Ser185, Glu319 und His415, wobei das Serin in das katalytische Motiv G-E-S-A-G eingebettet ist.
Während der Reaktion setzte die TfCa auch Hydrolyseprodukte aus PET-Fasern und -Filmen frei. Der Nachweis der Hydrolyse erfolgte durch Umkehrphasen-Hochleistungsflüssigkeitschromatographie der Abbauprodukte und bei den PET-Filmen zusätzlich mittels Rasterelektronenmikroskopie. Dabei zeigte die Carboxylesterase verglichen mit anderen PET-Hydrolasen eine geringere Effizienz, was durch die Lage des aktiven Zentrums in einer Bindungstasche und der daraus folgenden schlechten Zugänglichkeit für polymere Substrate begründet werden kann. Bei der Hydrolyse der viel kleineren CTR war die TfCa deutlich effektiver, was auf eine höhere Spezifität gegenüber kurzkettigen PET Substraten hinweist.
3
Dubelley, Florence. "Mécanismes de dégradation des enveloppes barrières pour application panneaux isolants sous vide". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI007/document.
Abstract (sommario):
Le panneau isolant sous vide, PIV est principalement constitué d’un matériau de cœur nano-poreux encapsulé sous vide par une enveloppe barrière multicouche polymère-métal. Dans l’objectif d’étendre le domaine d’emploi des PIV sur le marché de l’isolation thermique du bâtiment, il est nécessaire d’améliorer les performances d’étanchéités et la résistance en température et humidité des complexes barrières métallisés, ces derniers représentant le point faible des PIV. Ce travail a pour objectif d’identifier les différentes modifications subies par ces complexes au cours de leurs fonctionnement et de déterminer les mécanismes à l’origine de leur dégradation prématurée. Des vieillissements à 70 °C et 90 %RH (conditions maximales d’utilisations identifiées pour le bâtiment français) ont été réalisés à la fois sur les composants, sur les complexes et sur les PIV pour des temps compris entre 1 et 870 jours. A l’échelle microscopique, la dégradation chimique du polyéthylène téréphtalate (PET) et de l’adhésif polyuréthane (PU) ont été étudiées par spectroscopie IR. Des marqueurs de l’hydrolyse ont ainsi pu être identifiés et ont permis de mettre en évidence la dégradation de ces deux composants au sein du complexe. L’hydrolyse ayant des répercussions directes sur les propriétés mécaniques des polymères explique la fragilisation à long terme de l’enveloppe. L’action de l’eau entraine également un gonflement et une plastification du PET, mis en évidence par mesure gravimétrique. Ces derniers peuvent entrainer des modifications de microstructure ayant des répercussions directes sur les mécanismes de transports des molécules d’eau et ainsi participer à la fragilisation du complexe. A l’échelle macroscopique, des mesures fines de retrait des films polymères ont été réalisées. Ces dernières ont été corrélées aux différentes délaminations de l’enveloppe barrière. Des analyses aux interfaces ont permis de déterminer le mode de rupture, adhésif ou cohésifVacuum Insulation Panels (VIPs) were already developed some time ago for low-temperature applications such as refrigerators. More recently, they have been used for the building application. They consist of a fine powder or fiber core material (fumed silica, glass fiber, PU foam) enveloped by a polymer-metal. The latter is responsible for preventing gas and water molecules from breaking the vacuum. Nevertheless, the use of VIPs for this application was limited for applications in severe conditions as for example: temperature, humidity and mechanical load. At high temperature and/or humidity, the most critical component of a VIP is the envelope: both for the tightness point of view and for its degradation. Consequently in these conditions, the vacuum was degraded and durability of the panel performance was decreased sharply.This work focuses on the degradation mechanisms of the polymer-metal envelope. The effect of hygrothermal ageing (70 °C and 90 %RH) on envelope was investigated at different scales: Microscopic: High humidity is at the origin of the hydrolysis of some components such as Polyethylene terephthalate (PET) and polyurethane adhesive (PU). Hydrolysis is directly at the origin of the changes mechanical properties, leading to embrittlement of the complex. An additional microstructural modifications was evidence in PET at high humidity and also contributes to embrittlement of the complex. Macroscopic: shrinkage of polymer film seems to be the origin of debonding in polymer-metal multilayer
4
Breche, Quentin. "Copolymères triblocs biodégradables PLA-b-PEG-b-PLA pour ingénierie tissulaire : Caractérisation et modélisation de l'évolution de leurs propriétés mécaniques au cours de leur dégradation par hydrolyse". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI068/document.
Abstract (sommario):
L’ingénierie tissulaire est une méthode de reconstruction d’organes et de tissus vivants. Elle consiste à ensemencer et faire coloniser un implant spécifique appelé scaffold par des cellules. Ce scaffold est un matériau architecturé doté d’une géométrie adaptée à l’organe à reconstruire. Sa fonction est de servir de guide et de support de régénération au tissu. Afin d’éviter les conséquences à long terme de la présence d’un implant synthétique dans l’organisme (risque de rejet, inflammation ...) l’idéal est d’utiliser un matériau biorésorbable qui, se dégradant au fur et à mesure de la reconstruction, laisse place aux néo-tissus formés. Les polymères biorésorbables sont, grâce à la vaste gamme de propriétés qu’ils proposent, les meilleurs candidats pour ce genre d’applications. Un polymère biorésorbable particulièrement intéressant est le PLA-b-PEG-b-PLA. En effet, celui-ci est biocompatible et possède, par sa structure tribloc, une potentielle vaste gamme de propriétés physiques et mécaniques. La réussite de la reconstruction tissulaire nécessite une parfaite connaissance du comportement mécanique du matériau constituant le scaffold ainsi que son évolution au cours de la dégradation.L’objectif de cette thèse est la caractérisation expérimentale et la modélisation du comportement mécanique des polymères PLA-b-PEG-b-PLA au cours de leur dégradation. L’intérêt est de fournir des outils de dimensionnement de scaffolds biorésorbables pour l’ingénierie tissulaire. Dans un premier temps, des essais de traction-relaxation ont été conduits sur un PLA-b-PEG-b-PLA à différents temps de dégradation. Afin de réaliser ces essais dans des conditions proches de celles rencontrées in vivo, un dispositif expérimental permettant d’accomplir des essais mécaniques en milieu immergé à une température de 37°C a été mis au point. A partir de ces essais, un modèle viscoélastique linéaire capable de prendre en compte la variation des propriétés mécaniques au cours de la dégradation pour de faibles déformations a été réalisé. Dans un second temps, afin de modéliser le comportement mécanique dans une gamme plus large de déformations, un modèle viscoélastique non-linéaire a été développé. Il s’agit d’un modèle quasi-linéaire viscoélastique adaptatif capable de prédire les courbes de traction-relaxation à différents niveaux de déformation ainsi que la perte de propriétés mécaniques au cours de la dégradation. Lors de la troisième partie, des PLA-b-PEG-b-PLA de compositions et masses molaires différentes ont été caractérisés afin d’étudier l’influence de la structure originelle du polymère sur leurs propriétés mécaniques et leur évolution au cours de la dégradation. La capacité du modèle viscoélastique linéaire précédemment développé à prédire le comportement des différents polymères a alors été discutée. Dans une dernière partie, le modèle viscoélastique linéaire dégradable a été utilisé pour simuler numériquement le comportement mécanique d’un tricot potentiellement utilisable en ingénierie tissulaireTissue engineering is an interdisciplinary field that applies the principles of engineering and biological science toward the development of biological substitutes that restore, maintain or improve the development of a whole organ by tissue reconstruction. It consists in seeding an implant called scaffold with cells taken from the patient and cultivated in vitro. The cells will then colonize and recreate tissue that takes the shape of the scaffold. The scaffold is an architecture biomaterial specifically designed for a considered organ. The knowledge of mechanical properties of the scaffold is particularly important. Indeed, it often must be used as a mechanical substitute to the injured organ. Moreover, its mechanical properties must be compatible with those of the host tissue to allow a good tissue regeneration. The main advantage of using biodegradable materials is their degradation along the regeneration process. It means that the material no longer remains in the body at long term avoiding toxicity and inflammation risks. Among biodegradable materials, polymers are particularly interesting due to their large range of properties. A very good candidate for tissue engineering applications is the PLA-b-PEG-b-PLA biodegradable triblock copolymer. This polymer is biocompatible and possesses a good properties modulation. To allow a good tissue reconstruction, the knowledge of the mechanical properties of the scaffold as well as their evolution during degradation is essential.The aim of this work is to characterize experimentally and model the mechanical behavior of the PLA-b-PEG-b-PLA and its evolution during degradation. The interest is to provide tools to size and simulate biodegradable scaffolds for tissue engineering applications. At first, tensile-relaxation tests has been realized on the polymer during different degradation times. In order to realize the mechanical tests in conditions closed to in vivo ones, a specific experimental device has been designed that allows From this tests, a linear viscoelastic model able to take into account the variations of mechanical properties during degradation for small strain has been developed. Then, in order to model the mechanical behavior in a larger range of strain, a non-linear viscoelastic model was realized. In a third part, different polymers PLA-b-PEG-b-PLA with different initial composition has been mechanically characterized in order to study the influence of the original structure on mechanical properties and their evolution during degradation. To finish, the degradable linear viscoelastic model will be used to simulate numerically the mechanical behavior of a knitted textile for potential applications in tissue engineering
5
Irankunda, Rachel. "Nickel Chelating Peptides & Chromatography : From Peptides Separation Simulation up to their Antioxidant Activities - related Applications". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0213.
Abstract (sommario):
Les peptides chélateurs de métaux (PCMs), issus d'hydrolysats de protéines, présentent diverses applications dans les domaines de la nutrition, de la pharmacie, des cosmétiques, etc. Cependant, l'approche empirique généralement utilisée pour découvrir des peptides bioactifs à partir d'hydrolysats est longue et coûteuse en raison de nombreuses étapes de fractionnement, de séparation et d'évaluation des activités biologiques. Cette thèse a donc pour but de développer une nouvelle approche pour la prédiction de la séparation des PCMs en utilisant la modélisation et la simulation chromatographiques basées sur l'analogie entre la chromatographie d'affinité sur ions métalliques immobilisés (IMAC) et la résonance plasmonique de surface (SPR). Pour la première fois, l'analogie SPR-IMAC a été étudiée expérimentalement sur 22 peptides et 70% d'entre eux ont validé cette analogie, puisque les peptides bien retenus en IMAC étaient également dotés d'une bonne affinité pour Ni2+ en SPR. Dans un deuxième temps, des peptides ayant une forte affinité pour Ni2+ (c'est-à-dire une faible constante de dissociation KD en SPR et un temps de rétention élevé en IMAC) ont été utilisés pour étudier la simulation des profils de concentration de peptides à la sortie de la colonne en IMAC. La connaissance des isothermes d'adsorption étant nécessaire pour effectuer la simulation, il a fallu développer une méthodologie pour prédire les paramètres de l'isotherme de Langmuir en IMAC à partir des données SPR. La simulation a été évaluée en comparant les temps de rétention expérimentaux et simulés qui devraient être proches pour une prédiction fiable. Par conséquent, plusieurs approches ont été étudiées pour déterminer les paramètres de sorption de Langmuir. L‘approche la plus intéressante a introduit un facteur correctif sur la capacité d'adsorption maximale qmax seulement. En effet, l'affinité des peptides pour le Ni2+ immobilisé étant supposée constante quelle que soit technologie utilisée (SPR vs. IMAC), la constante d'affinité KA n'a pas été modifiée. Parallèlement, les applications industrielles des PCMs et des hydrolysats peptidiques ont été étudiées. Tout d'abord, des hydrolysats de protéines de pois ont été produits par protéolyse enzymatique soit avec l'Alcalase® suivi de la Flavourzyme® (Alc+Flav≤1kDa), soit par la Protamex® suivi de la Flavourzyme® (Prot+Flav≤1kDa). La technologie SwitchSENSE® a mis en évidence la présence de peptides chélateurs de Ni2+ et les tests antioxydants ont montré que l'hydrolysat Prot+Flav≤1kDa avait une activité antiradicalaire et un pouvoir réducteur plus élevés, liés à son degré d'hydrolyse plus élevé et à la quantité de peptides de petite taille. Les hydrolysats de protéines de pois et les PCMs ont ensuite été étudiés pour leur capacité à inhiber l'oxydation des lipides dans les émulsions. Ils ont ralenti l'oxydation des lipides par chélation des métaux pro-oxydants (tels que Fe2+) en réduisant les produits d'oxydation primaires et secondaires, responsables de la détérioration des produits contenant des lipides. Ainsi, les hydrolysats de pois et les PCMs pourraient être utilisés comme antioxydants dans les produits alimentaires et cosmétiques, comme alternatives aux produits chimiques tels que l'EDTA, le BHT et le TBHQMetal-Chelating Peptides (MCPs), from protein hydrolysates, present various applications in nutrition, pharmacy, cosmetic etc. Yet, the empirical approach generally used to discover bioactive peptides from hydrolysates is time consuming and expensive due to many steps of fractionation, separation and biological activities evaluation. Thus, this PhD aimed to develop a novel approach for MCPs separation prediction using chromatography modelling and simulation based on the analogy between Immobilized Metal ion Affinity Chromatography (IMAC) and Surface Plasmon Resonance (SPR). For the first time, the SPR-IMAC analogy was experimentally investigated on 22 peptides and 70% of them validated this analogy, since peptides well retained in IMAC were also endowed with a good affinity for Ni2+ in SPR. In the second time, peptides with high affinity for Ni2+ (i.e low dissociation constant KD in SPR and a high retention time in IMAC) were used to study the modelling and simulation of peptide concentration profiles at the column outlet in IMAC. Since knowledge of adsorption isotherms was required to perform simulation, it was necessary to develop a methodology for predicting Langmuir isotherm parameters in IMAC from SPR data. The validity of simulation was evaluated by comparing experimental and simulated retention times that should be close for reliable prediction. Therefore, several approaches were evaluated to determine Langmuir sorption parameters, the most interesting one introduces a correction factor on the maximum adsorption capacity qmax alone, assuming that the affinity of peptides for immobilized Ni2+ did not change depending on the technology used (SPR vs. IMAC), thus affinity constant KA was not modified. Meanwhile, industrial application of MCPs and hydrolysates were studied. First, pea protein hydrolysates were produced by either Alcalase® followed by Flavourzyme® (Alc+Flav≤1kDa) or Protamex® followed by Flavourzyme® (Prot+Flav≤1kDa). SwitchSENSE® technology evidences the presence of Ni2+ chelating peptides and antioxidants tests showed that Prot+Flav≤1kDa has higher radical scavenging and reducing power, related to its higher degree of hydrolysis and small-size peptides quantity. Secondly, pea hydrolysates and MCPs were investigated for their ability to inhibit the lipid oxidation in emulsions. They slowed down lipid oxidation through chelation of prooxidant (metals such as Fe2+) reducing primary and secondary oxidation products responsible of deterioration of lipid containing products. Thus, pea hydrolysates and MCPs could be used as antioxidants in food and cosmetic products, as alternative to chemicals such as EDTA, BHT and TBHQ
6
Peres, Durand Sylvie. "Etude physico-chimique de l'élaboration de gels de titane par le procédé PEM en milieu micellaire inverse decane/TX35/H2O-H2O2". Montpellier 2, 1993. http://www.theses.fr/1993MON20207.
Abstract (sommario):
Nous avons caracterise les gels de titane formes par le procede sol-gel, en milieu micellaire inverse decane/tx35/h(2)o-h(2)o(2). L'isopropoxyde de titane, solubilise dans le decane, polymerise par un mecanisme d'hydrolyse et de condensation avec une vitesse qui est controlee par la frequence des echanges inter-micellaires, et par la quantite d'eau oxygenee contenue dans les micelles inverses. L'etude physico-chimique de la solution micellaire inverse par viscosite et par diffusion de la lumiere montre qu'elle est constituee de petits agregats de forme allongee, qui ne solubilisent que 8 molecules d'eau oxygenee par molecule de tensioactif (tx35). Nous avons determine les cinetiques de gelification de l'oxyde de titane en fonction de 3 parametres experimentaux, le taux d'hydratation de la micelle, n, le taux d'hydrolyse de l'alcoxyde, h, et la molalite de l'alcoxyde, m. La formation des gels, en presence d'eau oxygenee, est plus rapide que lorsqu'on utilise l'eau, dans les memes conditions de h, n et m. L'etude physico-chimique des gels par differentes techniques comme l'analyse thermique, la diffraction des rayons x et des electrons, les isothermes d'adsorption, la microscopie electronique, la thermoporometrie et la diffusion centrale des rayons x, montrent que les gels fabriques en presence d'eau oxygenee ont une meilleure resistance mecanique que ceux formes en presence d'eau; ce sont des solides mesoporeux dont les pores, en forme de bouteille, ont un diametre de 4 nm. Les agregats primaires (dont la taille est d'environ 100 nm) sont constitues de barreaux interconnectes de 2 nm de longueur. Ils ont une structure fractale, et sont formes par un processus d'agregation amas-amas controle par la reaction chimique
7
Prairie, Natalie Paula. "The cardio-renal effect of pea protein hydrolysate in a chronic kidney disease rat model". 2012. http://hdl.handle.net/1993/5015.
Abstract (sommario):
Pea protein hydrolysate (PPH) has antihypertensive effects and prostanoids have been implicated in renal diseases. To investigate the role of PPH and prostanoids on renal and cardiovascular effects in cardio-renal disease, normal and diseased Han:SPRD-cy rats were given diets containing either 0, 0.5% or 1% PPH for 8 weeks. At termination, diseased rat kidneys displayed increased renal cyst growth, fibrosis, plasma creatinine and lower monocyte chemoattractant protein-1. Diseased rats also exhibited left ventricular (LV) hypertrophy, elevated systolic and diastolic blood pressures and LV end diastolic and systolic pressures. Four of five prostanoids were elevated in diseased rat kidneys. PPH attenuated systolic blood pressure, but not other components of the cardio-renal syndrome. PPH also increased select prostanoids in normal and diseased rats. Thus, dietary PPH attenuates hypertension in the Han:SPRD-cy rat, but does not ameliorate other components of disease, possibly due to increased prostanoid effects or an insufficient treatment length.
8
Chao, Dongfang. "Effects of thermal and high pressure treatments on structural and functional properties of pea seed (Pisum sativum L.) proteins and enzymatic protein hydrolysates". 2012. http://hdl.handle.net/1993/8103.
Abstract (sommario):
The effects of heat or high pressure treatment on the physicochemical and functional properties of pea proteins were evaluated by measuring polypeptide composition, hydrophobicity, solubility, gelation, emulsification, foaming, water-holding capacity and oil-holding capacity. Heat processing (≥ 70 °C) and high pressure treatment (≥ 200 MPa) led to significant increase (from 1.41 to 2.42) in hydrophobicity of native pea proteins. Native gel electrophoresis showed that the content of 11S protein decreased (increased aggregation) as intensity of pressure treatment was increased. In contrast the 7S protein was resistant to pressure-induced protein aggregation. The solubility and emulsifying capacity of pea proteins processed under higher pressure or heat at neutral pH had slight decreases probably due to the formation of aggregates. High pressure treatment of pea proteins led to reductions in the amount of protease required to produce renin-inhibitory peptides.
9
Pownall, Trisha. "Effects of molecular charge and hydrophobicity on the antioxidative properties of pea (Pisum sativum L.) protein hydrolysate fractions". 2009. http://hdl.handle.net/1993/21596.
10
Billig, Susan. "Abbau von Polyethylenterephthalat mit PET-Hydrolasen aus Thermobifida fusca KW3". Doctoral thesis, 2011. https://monarch.qucosa.de/id/qucosa%3A19688.
Abstract (sommario):
Der Actinomycet T. fusca KW3, isoliert aus Kompost, bildete während der Kultivierung im Mineralsalz-Spurenelement-Vitamin-Minimalmedium nach Zusatz von PET-Fasern eine 52 kDa Carboxylesterase (TfCa), welche effizient zyklische PET Trimere (CTR) hydrolysiert. Die TfCa besitzt einen pI von 4,8, eine Substratspezifität gegenüber kurzkettigen p-Nitrophenyl-Estern und wird durch Phenylmethylsulfonylfluorid (PMSF) und Tosyl-L-Phenylalanin-Chloromethylketon (TPCK) in der Aktivität gehemmt. Die Carboxylesterase hydrolysiert kein Cutin oder Poly-ε-caprolacton (PCL). CTR hingegen wurden durch die TfCa mit einem Km von 0,5 mM und einer Vmax von 9,3 μmol/min/mg bei optimalen Bedingungen (60°C, pH 6) hydrolysiert. Das aktive Zentrum der Carboxylesterase besteht aus den Aminosäuren Ser185, Glu319 und His415, wobei das Serin in das katalytische Motiv G-E-S-A-G eingebettet ist.
Während der Reaktion setzte die TfCa auch Hydrolyseprodukte aus PET-Fasern und -Filmen frei. Der Nachweis der Hydrolyse erfolgte durch Umkehrphasen-Hochleistungsflüssigkeitschromatographie der Abbauprodukte und bei den PET-Filmen zusätzlich mittels Rasterelektronenmikroskopie. Dabei zeigte die Carboxylesterase verglichen mit anderen PET-Hydrolasen eine geringere Effizienz, was durch die Lage des aktiven Zentrums in einer Bindungstasche und der daraus folgenden schlechten Zugänglichkeit für polymere Substrate begründet werden kann. Bei der Hydrolyse der viel kleineren CTR war die TfCa deutlich effektiver, was auf eine höhere Spezifität gegenüber kurzkettigen PET Substraten hinweist.:Inhaltsverzeichnis
1 Einführung 1
1.1 Actinomyceten 1
1.1.1 Klassifizierung 1
1.1.2 Thermobifida (Thermomonospora) fusca 2
1.2 Biopolyester Cutin und Suberin 4
1.2.1 Bestandteile des Cutins 4
1.2.2 Bestandteile des Suberins 5
1.2.3 Struktur der Biopolymere 7
1.3 Hydrolasen 12
1.3.1 Struktur und katalytischer Mechanismus 12
1.3.2 Carboxylesterasen 16
1.3.3 Lipasen 19
1.3.4 Cutinasen 22
1.4 Polyethylenterephthalat 23
1.4.1 Konventionelle PET-Faserbehandlung 24
1.4.2 Charakterisierung von PET 26
1.4.3 Biofunktionalisierung von PET 30
1.4.4 PET-Hydrolasen 38
1.5 Zielsetzung 49
2 Material und Methoden 50
2.1 Materialien 50
2.1.1 Verwendete Mikroorganismen 50
2.1.2 Verwendete Enzyme 50
2.1.3 Größenstandards 51
2.1.3.1 Low Molecular Weight Marker (GE Healthcare) 51
2.1.3.2 Roti®-Mark Standard (Fa. Carl Roth GmbH) 51
2.1.3.3 SpectraTM Multicolor Broad range Protein Ladder (Fermentas) 51
2.1.3.4 PageRulerTM plus prestained protein ladder (Fermentas) 51
2.1.3.5 Kalibrierungskit für pI Bestimmung (pH 3-10, GE Healthcare) 52
2.1.3.6 Kalibrierungskit für die Größenausschlusschromatographie (LMW, GE Healthcare) 52
2.1.4 Chemikalien 53
2.1.5 Geräte und Materialien 55
VI
2.1.6 Software 58
2.1.7 Nährmedien 58
2.1.8 Suberin- und Cutin-Präparationen 60
2.1.9 PET-Substrate für die Abbauuntersuchungen 60
2.1.10 Puffer und Lösungen 60
2.2 Mikrobiologische Methoden 65
2.2.1 Stammhaltung und Kultivierung 65
2.2.2 Mikroskopische Untersuchungen 65
2.2.3 Trockengewichtsbestimmung 65
2.3 Proteinchemische Methoden 66
2.3.1 Proteinaufreinigung der Wildtyp TfCa 66
2.3.2 Proteinaufreinigung der rekombinanten TfCa, TfCut1 und TfCut2 67
2.4 Analytische Methoden 67
2.4.1 Esterase-Aktivitätsbestimmung 67
2.4.1.1 Bestimmung mittels Spektrophotometer 68
2.4.1.2 Bestimmung mittels Plattenleser 68
2.4.2 Cutinase-Aktivitätsbestimmung 68
2.4.3 PCL-Abbauuntersuchung 69
2.4.3.1 Bestimmung mittels Hofbildung 69
2.4.3.2 Bestimmung mittels Plattenleser 69
2.4.4 Quantitative Protein-Bestimmung nach Bradford (1976) 69
2.4.5 SDS Polyacrylamidgelelektrophorese (SDS-PAGE) 70
2.4.5.1 Esteraseaktivitäts-Färbung 70
2.4.5.2 Coomassie-Färbung 71
2.4.5.3 Silberfärbung der Proteine 71
2.4.6 Bestimmung des pI 71
2.4.7 Bestimmung der Molaren Masse 72
2.4.8 Bestimmung der Temperatur und pH-Wert Stabilität 72
2.4.9 Bestimmung der Stabilität gegenüber Inhibitoren 72
2.4.10 Bestimmung der kinetischen Konstanten für die Hydrolyse von p-NP Ester 72
2.4.11 Bestimmung der kinetische Konstanten für die Hydrolyse von CTR 73
2.4.12 Bestimmung optimaler Temperatur und pH-Wert für die Hydrolyse von CTR 73
2.4.13 N-terminale Sequenzierung 73
2.4.14 MALDI-TOF Sequenzierung 74
2.4.15 Abbaustudien 74
VII
2.4.16 Analytik der PET Abbauprodukte 75
2.4.17 Konzentrationabhängige CTR-Abbaustudien 75
2.5 Homologie-Modelling der TfCa und weitere PET-Hydrolasen 76
3 Ergebnisse und Diskussion 77
3.1 Screening nach PET-Hydrolasen aus T. fusca 77
3.1.1 Wachstum von T. fusca KW3 im Czapek-Medium 77
3.1.2 Wachstum von T. fusca KW3 im MSV-Medium 78
3.1.2.1 Esterasebildung mit verschiedenen synthetischen und natürlichen Polyestern 78
3.1.2.2 Esterasebildung mit einer Suberinpräparation 81
3.1.2.3 Esterasebildung mit PET-Fasern 83
3.1.3 Esterasebildung bei T. fusca KW3 DSM 6013, T. fusca DSM 43792 und DSM 43793 mit PET-Fasern und Diethylterephthalat 85
3.2 Charakterisierung der PET-Hydrolasen aus T. fusca KW3 95
3.2.1 Aufreinigung 95
3.2.1.1 Aufreinigung der TfCa 95
3.2.1.2 Aufreinigung der rekombinanten PET-Hydrolasen 105
3.2.2 pI der TfCa 113
3.2.3 Molare Masse der TfCa 113
3.2.4 Temperatur- und pH-Stabilität der TfCa 114
3.2.5 Wirkung von Inhibitoren auf die TfCa 117
3.2.6 Kinetik der Hydrolyse von verschiedenen Esterasesubstraten durch die TfCa 118
3.2.7 Optimale Temperatur und optimaler pH-Wert der CTR-Hydrolyse durch die TfCa 119
3.2.8 Cutinaseaktivität der TfCa 120
3.2.9 PCL-Abbau durch die TfCa 121
3.2.10 N-terminale Sequenz der TfCa 122
3.2.11 MALDI-TOF Sequenzierung der TfCa 123
3.2.12 Homologie-Modeling der TfCa und Vergleich der Struktur mit anderen Hydrolasen 126
3.2.13 Vergleich der TfCa mit bekannten PET-Hydrolasen 128
3.3 Hydrolyse von PET Substraten durch prokaryotische und eukaryotische Hydrolasen 138
3.3.1 Partielle Hydrolyse von APET-Filmen durch die PET-Hydrolasen 140
3.3.2 Partielle Hydrolyse von PET-Fasern durch die PET-Hydrolasen 148
3.3.3 Hydrolyse von PET-Trimeren durch die PET-Hydrolasen 151
4 Zusammenfassung 165
VIII
5 Literaturverzeichnis 166
6 Publikationen 181
7 Poster und Vorträge 182
8 Lebenslauf 183
Atti di convegni sul tema "PET hydrolysate":
1
Asen, Nancy, e Rotimi Aluko. "Functional Properties of Enzymatic Pea Protein Hydrolysates That Inhibit in vitro Activities of Acetylcholinesterase and Butyrylcholinesterase". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ktht4252.
Abstract (sommario):
Overview: Alzheimer’s disease (AD) is a neurodegenerative disorder prevalent among the aged population with morbidity and mortality rate of ~ 12%. Research has linked the cause of this disorder to the loss of acetylcholine through excessive activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Therefore, a promising therapeutic approach for AD treatment is the inhibition of AChE/BChE activities. Common features of an AD brain include low levels of acetylcholine, the presence of amyloid-β peptides deposits and severe oxidative stress triggered by lipid peroxidation and formation of free radicals. Natural peptides that possess antioxidant and bioactivities could have prospects for use in AD management. Objectives: Optimize enzymatic hydrolysis of yellow field pea proteins into protein hydrolysates that possess antioxidant, anti-AChE and anti-BChE activities. Methods: Pea protein (70%) was hydrolyzed using six as alcalase (AH), chymotrypsin (CHH), flavourzyme (FZH), pancreatin (PCH), pepsin (PEH) and trypsin (TPH). The supernatants were sequentially passed through ultrafiltration (UF) membranes with molecular weight cut-off of 1, 3, 5 and 10 kDa to collect the permeates as < 1, 1-3, 3-5, and 5-10 kDa, respectively. The hydrolysates and UF fractions were screened for inhibition of linoleic acid peroxidation (LAP) in addition to radical scavenging (hydroxyl and superoxide) and anti-AChE/BChE properties.Results: Hydrolysates showed varying degrees of radicals scavenging and LAP, as well as anti-AChE and anti-BChE activities but the potency improved by >10% for most UF fractions. AH, FZH, PEH and the UF fractions (1-3 kDa) exhibited better and statistically significant (p<0.05) radical scavenging and AChE/BChE activities than other hydrolysates by 20-30% and 20-40% respectively at same concentrations (10-50 µg).Significance of study: The results suggest that pea protein-derived peptides could be potential candidates for use in the inhibition of AChE and BChE activities, which could provide therapeutic tools suitable for the prevention and treatment of AD.
2
LONGATI, A. A., R. C. GIORDANO, F. F. FURLAN e A. J. G. CRUZ. "BIOGAS FROM ANAEROBIC DIGESTION OF HEMICELLULOSE HYDROLYSATE: AN ECONOMIC PERSPECTIV". In XXII Congresso Brasileiro de Engenharia Química. São Paulo: Editora Blucher, 2018. http://dx.doi.org/10.5151/cobeq2018-pt.0344.
3
Varela, D., R. O’Hara e A. C. Neves. "BY-PRODUCTS OF THE WHELK PROCESSING INDUSTRY AS VALUABLE SOURCE OF ANTIOXIDANT PEPTIDES". In World Conference on Waste Management. The International Institute of Knowledge Management, 2021. http://dx.doi.org/10.17501/26510251.2021.1103.
Abstract (sommario):
The fish and shellfish industry processes 851,984 tonnes of fish per year worldwide. However, only 43% of that is consumed, and valuable proteins are processed as waste. Protein hydrolysates are widely used in food technology for their nutritional and functional properties. The goal of this project is to extract protein from whelk by-products derived from the shellfish processing industry and create protein hydrolysates that have marketable value. The by-products were divided into two types: raw (R) and cooked byproduct (C). The proteins were extracted using the pH shift method and quantified using the Bradford assay. It was possible to extract a maximum of 455 mg/g at a neutral pH, for which R had the highest protein yield. Proteins were also qualified using reverse phase high-performance liquid chromatography (RP-HPLC) that showed that R has more hydrophilic proteins while the C extracted protein showed more peaks in the hydrophobic phase. The Fourier-transform infrared spectroscopy (FTIR) indicated the presence of glutamine, tyrosine, and serine in the extracted proteins. Extracted proteins were then hydrolyzed using Alcalase and α-Chymotrypsin. It was possible to obtain higher degrees of hydrolysis (DH) using Alcalase. The hydrolysates were tested for antioxidant activity using the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical antioxidant assay. Alcalase hydrolysates showed to have overall lower IC50 for stabilization of the DPPH radical than α-Chymotrypsin, the lowest one being 13.92±1.57 µg/mL for the Alcalase hydrolyzed neutral proteins. The IC50 results obtained are significantly lower than the ones described in other studies using the same enzymes or other marine species. This can indicate that more heterogenous mixtures of by-product can originate extracted proteins that when hydrolyzed lead to higher radical scavenging activity, thus making shellfish industry by-product a sustainable and valuable source of antioxidant peptides. Keywords: Shellfish; Bioactive peptides; Protein extraction; Protein hydrolysates, Waste management, Nutraceuticals
4
Reinoso, Zain Sanchez, Jacinthe Thibodeau, Laila Ben Said, Ismail Fliss, Laurent Bazinet e Sergey Mikhaylin. "Bioactive Peptide Production from Slaughterhouse Blood Proteins: Impact of Pulsed Electric Fields and Ph on Enzyme Inactivation, Antimicrobial and Antioxidant Activities of Peptic Hydrolysates from Bovine and Porcine Hemoglobins". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/fsht2150.
Abstract (sommario):
Slaughterhouse blood is a valuable by-product since multiple bioactive compounds can be derived out of it. Its solid fraction consists mainly of hemoglobin, which is a good source of antimicrobial and antioxidant peptides that can be released by peptic hydrolysis. Nevertheless, this method has limitations such as low yield, expensive cost of enzyme process, and non-eco-friendly production (high energy consumption and chemical reagents requested). Amount the alternative green technologies for protein valorization, pulsed electric field (PEF) stands out since it allows modifying the physicochemical properties of proteins, promoting the enzymatic hydrolysis, enzyme inactivation, and bioactivity enhancement. Thus, this study aimed to evaluate the effect of PEF on the pepsin inactivation and biological activities (antimicrobial and antioxidant) in hemoglobin hydrolysates. Bovine and porcine hemoglobins were hydrolyzed with pepsin for 3 h (37°C, pH 3.0) and treated with PEF (73 pulses, 23.8kV/cm, 90Hz) to inactivate the enzyme. The hydrolysis degree was evaluated, which did not show significant changes after PEF-inactivation of pepsin, whereas the peptide population analysis by RP-UPLC-MS/MS showed some changes in PEF-treated hydrolysates over time, which suggested a residual pepsin activity. Additionally, the impact of pH (3, 7, and 10) on bioactivity was studied. PEF-treatments did not show a significant impact on antimicrobial (antibacterial, antifungal, and anti-yeast activities) and antioxidant activities (DPPH and ORAC). However, higher pH fostered stronger anti-yeast activity (R. mucilaginosa) and DPPH‐scavenging capacity, whereas pH 7 fostered the antifungal activity (M. racemosus). Even though some changes were observed in the peptide population, no negative effects of PEF were found for biological activities. Thus, the utilization of hemoglobin from the meat industry combined with PEF-treatment fits the circular economy concept since derived peptides can be recycled to protect meat and other products against microbial growth and oxidation.
5
Lu, Bing, Nihong Liu, Zhengxuan Li, Hubo Xu, Yanlei Li e Xiuying Tang. "Research on the influence factors of alkali hydrolysable nitrogen in coco-peat is determined by alkali N-proliferation method". In 2018 Detroit, Michigan July 29 - August 1, 2018. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2018. http://dx.doi.org/10.13031/aim.201801021.
Rapporti di organizzazioni sul tema "PET hydrolysate":
1
Cena, R. J., C. B. Thorsness, T. T. Coburn e B. E. Watkins. Second test of base hydrolysate decomposition in a 0.04 gallon per minute scale reactor. Office of Scientific and Technical Information (OSTI), ottobre 1994. http://dx.doi.org/10.2172/105852.
2
Cena, R. J., C. B. Thorsness, T. Coburn e B. E. Watkins. LLNL demonstration of base hydrolysate decomposition in a 0.035 gallon per minute scale reactor. Office of Scientific and Technical Information (OSTI), giugno 1994. http://dx.doi.org/10.2172/10170617.