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Gras hat ein hohes Potenzial als nachwachsender Rohstoff. Bei ungeeigneter Lagerung verderben Gräser allerdings innerhalb weniger Tage. Dieser Nachteil kann durch die Silierung des Grasschnittes behoben werden. Eines der wichtigsten in der Silage enthaltenen Produkte ist die Milchsäure. Um diese für weitere Aufarbeitungsschritte zugänglich zu machen, wird aus der Silage ein Presssaft hergestellt. Die Milchsäure wird aus einem Silagepresssaft mittels Extraktion durch ionische Flüssigkeiten isoliert. Dabei wird zum einen eine reine Milchsäure hergestellt, die z. B. für die Herstellung von Polymilchsäure genutzt werden kann. Zum anderen wird ein weniger aufgereinigter Extrakt gewonnen, der für die fermentative Produktion von L-Lysin und 1,2-Propandiol genutzt werden soll. Im Rahmen des Projekts erfolgt die gentechnische Optimierung von Corynebacterium glutamicum für die Umsetzung von Milchsäurezu L-Lysin. Die im nach der Pressung verbleibenden Presskuchen enthaltenen Grasfasern bestehen zu einem großen Teil aus Polysacchariden. Diese werden hydrolysiert und die dabei freigesetzten Zucker zu Grundchemikalien wie Ethanol oder Itakonsäure fermentiert. Im Rahmen einer vollständigen Nutzung der Silage wird das Raffinat aus der Milchsäureextraktion als Mediumsupplement in der Fermentation eingesetzt, was die Zugabe weiterer Medienbestandteile überflüssig macht. Die Rückstände der Hydrolysen und Fermentationen sollen darüberhinaus für die Herstellung von Biogas genutzt werden.
Helle Fensterprofilmaterialien : Alterungsverhalten auf Basis von peroxidisch vernetztem EPDM
(2010)
Gräser sind in der Lage, einen großen Teil der für eine biobasierte Wirtschaft benötigten Biomasse zur Verfügung zustellen. Um eine ganzjährige Nutzung des Grases zu gewährleisten, muss eine stabile Lagerung des Grases erreicht werden, was z. B. durch Silieren möglich ist. Die konservierende Wirkung der Silierung beruht auf der Bildung organischer Säuren. Um diese zu gewinnen, wird die Silage gepresst, die organischen Säuren über Flüssig/Flüssig-Extraktion aus dem Presssaft abgetrenntund mittels chromatographischer Methoden weiter aufgereinigt. Im präsentierten Konzept werden die im Presskuchen enthaltenen Lignocellulosen hydrolysiert und die erhaltenen Monosaccharide zu Ethanol fermentiert. Die Phenolsäuren, die in Gräsern die Rolle des Lignins übernehmen, können simultan mit der Hydrolyse der Polysaccharide enzymatisch abgetrennt und als Nebenprodukt gewonnen werden. Die nach der Abtrennung des Ethanols verbleibenden Fermentationsreststoffe werden für die Herstellung von Biogas verwendet.
Clostridium propionicum is the only organism known to ferment β-alanine, a constituent of coenzyme A (CoA) and the phosphopantetheinyl prosthetic group of holo-acyl carrier protein. The first step in the fermentation is a CoA-transfer to β-alanine. Subsequently, the resulting β-alanyl-CoA is deaminated by the enzyme β-alanyl-CoA:ammonia lyase (Acl) to reversibly form ammonia and acrylyl-CoA. We have determined the crystal structure of Acl in its apo-form at a resolution of 0.97 Å as well as in complex with CoA at a resolution of 1.59 Å. The structures reveal that the enyzme belongs to a superfamily of proteins exhibiting a so called “hot dog fold” which is characterized by a five-stranded antiparallel β-sheet with a long α-helix packed against it. The functional unit of all “hot dog fold” proteins is a homodimer containing two equivalent substrate binding sites which are established by the dimer interface. In the case of Acl, three functional dimers combine to a homohexamer strongly resembling the homohexamer formed by YciA-like acyl-CoA thioesterases. Here, we propose an enzymatic mechanism based on the crystal structure of the Acl·CoA complex and molecular docking. Proteins 2014; 82:2041–2053. © 2014 Wiley Periodicals, Inc.
Durch den Einsatz magnetisierbarer Partikel lassen sich Stoffwechselprodukte direkt und selektiv aus feststoffreichen Fermentationssuspensionen abtrennen. Im Gegensatz zu klassischen Adsorbermaterialien können magnetisierbare Partikel mit sehr geringen Durchmessern verwendet werden. Zur deren Abtrennung ist jedoch ein hoher Magnetfeldgradient notwendig. Dieser wird in der Regel durch in der Trennkammer bzw. dem Magnetfeld eingebrachte magnetisierbare Drähte realisiert. Bei der Auslegung der Drahtgitter ist ein Kompromiss zwischen Abtrennrate und Durchlässigkeit nötig. Die Ausrichtung der Drähte in Relation zum Magnetfeld, deren Abstand sowie die geometrische Anordnung können hierbei variiert werden. Zum Verständnis der Einflüsse auf das sich ausbildende Magnetfeld und die Fluiddynamik wurden Simulationen mit der Finite-Elemente-Methode durchgeführt und experimentell überprüft. Hierfür wurden die Drähte unter Variation von Anzahl, Richtung und Anordnung in den Hochgradient-Magnetseparator eingebracht. Erste Verifizierungen der Simulationen zeigen, dass die in Magnetfeldrichtung ausgerichteten Drähte (x-Achse) über die geringste Partikelrückhaltefähigkeit verfügen. Die Drähte der y- und z-Achse halten den größten Anteil der Magnetpartikel zurück, wobei die Drähte in y-Richtung den höchsten Feldgradienten ausbilden. Des Weiteren konnte gezeigt werden, dass eine rhomboedrische Drahtanordnung der kubischen vorzuziehen ist.
Der Erhalt möglichst hoher Zuckerkonzentrationen für nachfolgende Fermentationen und eine Steigerung der Produktivität sind Ziele der Hydrolyse bei hohen Feststoffkonzentrationen im Rahmen des Projekts „Lignocellulose Bioraffinerie“. Verwendet wird durch ein Organosolv-Verfahren aufgeschlossenes Buchenholz. Die Hydrolyse des Faserstoffes erfolgt mithilfe von CTec2-Enzymen (Fa. Novozymes). Zurzeit können unter Einsatz eines neuen Feststoffreaktors Cellulosefasern in einer Konzentration bis 400 g L⁻¹ enzymatisch hydrolysiert werden. Dabei werden Ausbeuten (g Glucose/g Cellulose im Faserstoff) bis 0,86 g g⁻¹ und Glucosekonzentrationenvon 120 g L⁻¹ erreicht. Ein Nachteil ist jedoch die hierbei auftretende Abnahme der Hydrolyseausbeuten. Zahlreiche Limitierungen bezüglich der Hydrolysierbarkeit von Lignocellulose werden zurzeit diskutiert und publiziert. Ziel der Untersuchungen ist die Identifizierung hydrolysehemmender Substanzen sowie die Erhöhung der Ausbeute an Zuckermonomeren durch den Einsatz lignolytischer Enzyme. Hierbei wird eine HPLC-MS-Methode zur Charakterisierung hemmender Substanzen eingesetzt, um potenzielle Inhibitoren zu erfassen.
Mouse nongenotoxic hepatocarcinogens phenobarbital (PB) and chlordane induce hepatomegaly characterized by hypertrophy and hyperplasia. Increased cell proliferation is implicated in the mechanism of tumor induction. The relevance of these tumors to human health is unclear. The xenoreceptors, constitutive androstane receptors (CARs), and pregnane X receptor (PXR) play key roles in these processes. Novel “humanized” and knockout models for both receptors were developed to investigate potential species differences in hepatomegaly. The effects of PB (80 mg/kg/4 days) and chlordane (10 mg/kg/4 days) were investigated in double humanized PXR and CAR (huPXR/huCAR), double knockout PXR and CAR (PXRKO/CARKO), and wild-type (WT) C57BL/6J mice. In WT mice, both compounds caused increased liver weight, hepatocellular hypertrophy, and cell proliferation. Both compounds caused alterations to a number of cell cycle genes consistent with induction of cell proliferation in WT mice. However, these gene expression changes did not occur in PXRKO/CARKO or huPXR/huCAR mice. Liver hypertrophy without hyperplasia was demonstrated in the huPXR/huCAR animals in response to both compounds. Induction of the CAR and PXR target genes, Cyp2b10 and Cyp3a11, was observed in both WT and huPXR/huCAR mouse lines following treatment with PB or chlordane. In the PXRKO/CARKO mice, neither liver growth nor induction of Cyp2b10 and Cyp3a11 was seen following PB or chlordane treatment, indicating that these effects are CAR/PXR dependent. These data suggest that the human receptors are able to support the chemically induced hypertrophic responses but not the hyperplastic (cell proliferation) responses. At this time, we cannot be certain that hCAR and hPXR when expressed in the mouse can function exactly as the genes do when they are expressed in human cells. However, all parameters investigated to date suggest that much of their functionality is maintained.
Humanized UGT2 and CYP3A transchromosomic rats for improved prediction of human drug metabolism
(2019)
Abstractauthoren Graphene oxide (GO) nanoparticles were incorporated in temperature-sensitive Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The nanoparticles increase the light absorption and convert light energy into heat efficiently. Thus, the hydrogels with GO can be stimulated spatially resolved by illumination as it was demonstrated by IR thermography. The temporal progression of the temperature maximum was detected for different concentrations of GO within the polymer network. Furthermore, the compatibility of PNIPAAm hydrogels with GO and cell cultures was investigated. For this purpose, culture medium was incubated with hydrogels containing GO and the viability and morphology of chinese hamster ovary (CHO) cells was examined after several days of culturing in presence of this medium.
The molecular events during nongenotoxic carcinogenesis and their temporal order are poorly understood but thought to include long-lasting perturbations of gene expression. Here, we have investigated the temporal sequence of molecular and pathological perturbations at early stages of phenobarbital (PB) mediated liver tumor promotion in vivo. Molecular profiling (mRNA, microRNA [miRNA], DNA methylation, and proteins) of mouse liver during 13 weeks of PB treatment revealed progressive increases in hepatic expression of long noncoding RNAs and miRNAs originating from the Dlk1-Dio3 imprinted gene cluster, a locus that has recently been associated with stem cell pluripotency in mice and various neoplasms in humans. PB induction of the Dlk1-Dio3 cluster noncoding RNA (ncRNA) Meg3 was localized to glutamine synthetase-positive hypertrophic perivenous hepatocytes, sug- gesting a role for β-catenin signaling in the dysregulation of Dlk1-Dio3 ncRNAs. The carcinogenic relevance of Dlk1-Dio3 locus ncRNA induction was further supported by in vivo genetic dependence on constitutive androstane receptor and β-catenin pathways. Our data identify Dlk1-Dio3 ncRNAs as novel candidate early biomarkers for mouse liver tumor promotion and provide new opportunities for assessing the carcinogenic potential of novel compounds.
Dexamethasone (DEX) is a potent and widely used anti-inflammatory and immunosuppressant glucocorticoid. It can bind and activate the pregnane X receptor (PXR), which plays a critical role as xenobiotic sensor in mammals to induce the expression of many enzymes, including cytochromes P450 in the CYP3A family. This induction results in its own metabolism. We have used a series of transgenic mouse lines, including a novel, improved humanized PXR line, to compare the induction profile of PXR-regulated drug-metabolizing enzymes after DEX administration, as well as looking at hepatic responses to rifampicin (RIF). The new humanized PXR model has uncovered further intriguing differences between the human and mouse receptors in that RIF only induced Cyp2b10 in the new humanized model. DEX was found to be a much more potent inducer of Cyp3a proteins in wild-type mice than in mice humanized for PXR. To assess whether PXR is involved in the detoxification of DEX in the liver, we analyzed the consequences of high doses of the glucocorticoid on hepatotoxicity on different PXR genetic backgrounds. We also studied these effects in an additional mouse model in which functional mouse Cyp3a genes have been deleted. These strains exhibited different sensitivities to DEX, indicating a protective role of the PXR and CYP3A proteins against the hepatotoxicity of this compound.
In the present work an optical sensor in combination with a spectrally resolved detection device for in-line particle-size-monitoring for quality control in beer production is presented. The principle relies on the size and wavelength dependent backscatter of growing particles in fluids. Measured interference structures of backscattered light are compared with calculated theoretical values, based on Mie-Theory, and fitted with a linear least square method to obtain particle size distributions. For this purpose, a broadband light source in combination with a process-CCD-spectrometer (charge ? coupled device spectrometer) and process adapted fiber optics are used. The goal is the development of an easy and flexible measurement device for in-line-monitoring of particle size. The presented device can be directly installed in product fill tubes or vessels, follows CIP- (cleaning in place) and removes the need of sample taking. A proof of concept and preliminary results, measuring protein precipitation, are presented.
A future bio-economy should not only be based on renewable raw materials but also in the raise of carbon yields of existing production routes. Microbial electrochemical technologies are gaining increased attention for this purpose. In this study, the electro-fermentative production of biobutanol with C. acetobutylicum without the use of exogenous mediators is investigated regarding the medium composition and the reactor design. It is shown that the use of an optimized synthetic culture medium allows higher product concentrations, increased biofilm formation, and higher conductivities compared to a synthetic medium supplemented with yeast extract. Moreover, the optimization of the reactor system results in a doubling of the maximum product concentrations for fermentation products. When a working electrode is polarized at −600 mV vs. Ag/AgCl, a shift from butyrate to acetone and butanol production is induced. This leads to an increased final solvent yield of Yᴀᴃᴇ = 0.202 gg⁻¹ (control 0.103 gg⁻¹), which is also reflected in a higher carbon efficiency of 37.6% compared to 23.3% (control) as well as a fourfold decrease in simplified E-factor to 0.43. The results are promising for further development of biobutanol production in bioelectrochemical systems in order to fulfil the principles of Green Chemistry.
Throughout the last decade, and particularly in 2022, water scarcity has become a critical concern in Morocco and other Mediterranean countries. The lack of rainfall during spring was worsened by a succession of heat waves during the summer. To address this drought, innovative solutions, including the use of new technologies such as hydrogels, will be essential to transform agriculture. This paper presents the findings of a study that evaluated the impact of hydrogel application on onion (Allium cepa) cultivation in Meknes, Morocco. The treatments investigated in this study comprised two different types of hydrogel-based soil additives (Arbovit® polyacrylate and Huminsorb® polyacrylate), applied at two rates (30 and 20 kg/ha), and irrigated at two levels of water supply (100% and 50% of daily crop evapotranspiration; ETc). Two control treatments were included, without hydrogel application and with both water amounts. The experiment was conducted in an open field using a completely randomized design. The results indicated a significant impact of both hydrogel-type dose and water dose on onion plant growth, as evidenced by various vegetation parameters. Among the hydrogels tested, Huminsorb® Polyacrylate produced the most favorable outcomes, with treatment T9 (100%, HP, 30 kg/ha) yielding 70.55 t/ha; this represented an increase of 11 t/ha as compared to the 100% ETc treatment without hydrogel application. Moreover, the combination of hydrogel application with 50% ETc water stress showed promising results, with treatment T4 (HP, 30 kg, 50%) producing almost the same yield as the 100% ETc treatment without hydrogel while saving 208 mm of water.