Refine
Year of publication
- 2023 (70) (remove)
Institute
- Fachbereich Gestaltung (40)
- Fachbereich Medizintechnik und Technomathematik (7)
- INB - Institut für Nano- und Biotechnologien (7)
- Fachbereich Chemie und Biotechnologie (6)
- Fachbereich Luft- und Raumfahrttechnik (4)
- ECSM European Center for Sustainable Mobility (3)
- Fachbereich Energietechnik (3)
- Fachbereich Maschinenbau und Mechatronik (3)
- Fachbereich Wirtschaftswissenschaften (3)
- Nowum-Energy (3)
Has Fulltext
- yes (70) (remove)
Document Type
- Bachelor Thesis (41)
- Article (24)
- Book (3)
- Administrative publication (1)
- Talk (1)
Keywords
- Fotografie (4)
- Typografie (4)
- Illustration (3)
- Kinder (3)
- Produktdesign (3)
- nachhaltig (3)
- Bacillaceae (2)
- Biotechnological application (2)
- Corporate Design (2)
- Datenvisualisierung (2)
- Editorial Design (2)
- Graphic Novel (2)
- Keramik (2)
- Künstliche Intelligenz (2)
- Licht (2)
- Medienkompetenz (2)
- Musik (2)
- Nachhaltigkeit (2)
- Subtilases (2)
- Subtilisin (2)
- interaktiv (2)
- (Poly)saccharides (1)
- 3D Scan (1)
- Abwechslung (1)
- Acyl-amino acids (1)
- Aeroelasticity (1)
- Aloe vera (1)
- Aminoacylase (1)
- Amtliche Mitteilungen (1)
- Analoge und Digitale Welt (1)
- Anammox (1)
- Architectural design (1)
- Architektur (1)
- Aufklärung (1)
- Automotive safety approach (1)
- Autonomy (1)
- Bachelor (1)
- Bacterial cellulose (1)
- Berlin (1)
- Bioabsorbable (1)
- Blade element method (1)
- Blog (1)
- Bookazine (1)
- Broad pH spectrum (1)
- CFD (1)
- Capacitive field-effect sensor (1)
- Carbon sources (1)
- Cellulose nanostructure (1)
- Chaperone co-expression (1)
- Charging station (1)
- Chondroitin sulfate (1)
- Cost-effectiveness (1)
- Crashworthiness (1)
- Culture media (1)
- Daniele Ganser (1)
- Depressionen (1)
- Dienstplanung (1)
- Dietary supplements (1)
- Digitales Lernen (1)
- Dokumentarfilm (1)
- Dokumentarfotografie (1)
- Dokumentation (1)
- Drag estimation (1)
- Dänisch (1)
- EMS (1)
- Editorial (1)
- Editorial-Design (1)
- Effizienz (1)
- Electronic vehicle (1)
- Eltern (1)
- Emotionen (1)
- Energiemanagement (1)
- Enma (1)
- Enterprise information systems (1)
- Experimente (1)
- Familie (1)
- Farbe (1)
- Farbwechsel (1)
- Fassadenverkleidung (1)
- Fault approximation (1)
- Fault detection (1)
- Finite element method (1)
- Fliesen (1)
- Flut (1)
- Flächennutzung (1)
- Formel 1 (1)
- Fotoinstallation (1)
- Frau (1)
- Freiheit (1)
- Full-vehicle crash test (1)
- Gaming Maus (1)
- Gaming Produkte (1)
- Gefahr (1)
- Generative Gestaltung (1)
- Generatives Design (1)
- Geometrisch (1)
- Geriatric (1)
- Gesundheitsförderung (1)
- Glucosamine (1)
- Gold nanoparticles (1)
- Grotesk (1)
- Halotolerant protease (1)
- Hebamme (1)
- High-field NMR (1)
- Hip fractures (1)
- Hochwasserkatastrophe (1)
- Holzverbindungen (1)
- Inclusion bodies (1)
- Information extraction (1)
- Informationsdesign (1)
- Inklusion (1)
- Installation (1)
- Interaktive Gestaltung (1)
- Interessen (1)
- Interview (1)
- Inverse scattering problem (1)
- Iran (1)
- Juli21 (1)
- KI Kunst (1)
- Kampagne (1)
- Kind (1)
- Klassische Musik (1)
- Klettern (1)
- Kommunikation (1)
- Konkurrenz (1)
- Kontaktabbruch (1)
- Konzerthaus (1)
- Kreativität (1)
- Krebs (1)
- Künstliche Intelligenz (KI) (1)
- Label-free detection (1)
- Lampe (1)
- Landwirt (1)
- Landwirtschaft (1)
- Leben (1)
- Lernen (1)
- Lesesessel (1)
- Leuchte (1)
- Local path planning (1)
- Lokal (1)
- Luftreiniger (1)
- MCDA (1)
- Magazin (1)
- Mainstream (1)
- Medien (1)
- Medienscouts (1)
- Medizindesign (1)
- Medusomyces gisevi (1)
- Menschen (1)
- Mental Health (1)
- Minimalismus (1)
- Model-driven software engineering (1)
- Modular (1)
- Modularität (1)
- Monster (1)
- Multicell (1)
- Multimedia (1)
- Multiplexing (1)
- Multirotor UAS (1)
- Museum (1)
- Natur (1)
- Nitrogen removal (1)
- Obstacle avoidance (1)
- Online-Radikalisierung (1)
- Onlinehandel (1)
- Onlinepräsenz (1)
- OpenEMS (1)
- Organic acids (1)
- Parking (1)
- Partial nitritation (1)
- Philipp Hübl (1)
- Pix2Pix (1)
- Polster (1)
- Polylactide acid (1)
- Polysaccharides (1)
- Portrait (1)
- Prevention (1)
- Produkt Design (1)
- Propeller (1)
- Propeller elasticity (1)
- Prophylaxis (1)
- Prävention (1)
- Prüfungsordnung (1)
- Psychotherapie (1)
- Publikation (1)
- Rabbit Hole (1)
- Raumatmosphäre (1)
- Regalsystem (1)
- Reservation system (1)
- Resistive temperature detector (1)
- Ressourcenschonung (1)
- Revolution (1)
- Rivalität (1)
- Router (1)
- Rüster (1)
- Schichtarbeit (1)
- Schlafstörungen (1)
- Schlepper (1)
- Schlüter (1)
- Schraffur (1)
- Schönheit (1)
- Seamlessconnection (1)
- Selbstzensur (1)
- Siebdruck (1)
- Silk fibroin (1)
- Simulation (1)
- Skandinavien (1)
- Smarthome (1)
- Smartwatch (1)
- Social Media Kampagne (1)
- Software and systems modeling (1)
- Soziale Medien (1)
- Sozialer Wohnungsbau (1)
- Spectroscopy (1)
- Spiele (1)
- Sport (1)
- Start-up (1)
- Streptomyces griseus (1)
- Streptomyces lividans (1)
- Stuhl (1)
- Therapeutensuche (1)
- Therapieplatzsuche (1)
- Tiere (1)
- Traktor (1)
- Transkulturen (1)
- UAV (1)
- UX-Design (1)
- Utilization improvement (1)
- Verschwörungstheorien (1)
- Vibrio natriegens (1)
- Voltfang (1)
- Wandverkleidung (1)
- Waschmaschine (1)
- Wastewater (1)
- Wifi (1)
- Wind milling (1)
- Wind tunnel experiments (1)
- Wissensvermittlung (1)
- Zen (1)
- Zensur (1)
- additive manufacturing (1)
- amperometric biosensors (1)
- audiovisuell (1)
- auswechseln (1)
- bio-methane (1)
- biocompatible (1)
- biodegradabl (1)
- bubble column (1)
- children (1)
- conceptual design (1)
- distribution grid simulation (1)
- e-mobility (1)
- eVTOL development (1)
- eVTOL safety (1)
- encapsulation materials (1)
- entspannen (1)
- factory planning (1)
- fibroin (1)
- gendern (1)
- industrial design (1)
- manufacturing flexibility (1)
- methanation (1)
- mix flexibility (1)
- modular (1)
- plug flow reactor (1)
- power-to-gas (1)
- qNMR (1)
- recombinant expression (1)
- recyclebar (1)
- reparierbar (1)
- schlafen (1)
- smart-charging (1)
- volume flexibility (1)
- α-aminoacylase (1)
- ε-lysine acylase (1)
Zugriffsart
- weltweit (39)
- campus (16)
- fachbereichsweit (FB4) (12)
In this work, the effects of carbon sources and culture media on the production and structural properties of bacterial cellulose (BC) synthesized by Medusomyces gisevii have been studied. The culture medium was composed of different initial concentrations of glucose or sucrose dissolved in 0.4% extract of plain green tea. Parameters of the culture media (titratable acidity, substrate conversion degree etc.) were monitored daily for 20 days of cultivation. The BC pellicles produced on different carbon sources were characterized in terms of biomass yield, crystallinity and morphology by field emission scanning electron microscopy (FE-SEM), atomic force microscopy and X-ray diffraction. Our results showed that Medusomyces gisevii had higher BC yields in media with sugar concentrations close to 10 g L−1 after a 18–20 days incubation period. Glucose in general lead to a higher BC yield (173 g L−1) compared to sucrose (163.5 g L−1). The BC crystallinity degree and surface roughness were higher in the samples synthetized from sucrose. Obtained FE-SEM micrographs show that the BC pellicles synthesized in the sucrose media contained densely packed tangles of cellulose fibrils whereas the BC produced in the glucose media displayed rather linear geometry of the BC fibrils without noticeable aggregates.
Subtilisins from microbial sources, especially from the Bacillaceae family, are of particular interest for biotechnological applications and serve the currently growing enzyme market as efficient and novel biocatalysts. Biotechnological applications include use in detergents, cosmetics, leather processing, wastewater treatment and pharmaceuticals. To identify a possible candidate for the enzyme market, here we cloned the gene of the subtilisin SPFA from Fictibacillus arsenicus DSM 15822ᵀ (obtained through a data mining-based search) and expressed it in Bacillus subtilis DB104. After production and purification, the protease showed a molecular mass of 27.57 kDa and a pI of 5.8. SPFA displayed hydrolytic activity at a temperature optimum of 80 °C and a very broad pH optimum between 8.5 and 11.5, with high activity up to pH 12.5. SPFA displayed no NaCl dependence but a high NaCl tolerance, with decreasing activity up to concentrations of 5 m NaCl. The stability enhanced with increasing NaCl concentration. Based on its substrate preference for 10 synthetic peptide 4-nitroanilide substrates with three or four amino acids and its phylogenetic classification, SPFA can be assigned to the subgroup of true subtilisins. Moreover, SPFA exhibited high tolerance to 5% (w/v) SDS and 5% H₂O₂ (v/v). The biochemical properties of SPFA, especially its tolerance of remarkably high pH, SDS and H₂O₂, suggest it has potential for biotechnological applications.
„ALIGN“ ist ein smartes Möbelsystem, das den individuellen Lebensstil und die Werte der heutigen Gesellschaft widerspiegelt. Es bietet ausreichend Stauraum und ermöglicht es, Objekte gezielt in Szene zu setzen oder in den Hintergrund zu rücken. Das vielseitige System passt sich an unterschiedliche Raum- und Nutzungsszenarien an. Es ermöglicht die individuelle Gestaltung des Wohnraums nach persönlichen Vorlieben und hilft, den Herausforderungen des modernen Lebens gerecht zu werden. „ALIGN“ – eine passende Lösung für jedes Problem.
There is a growing demand for more flexibility in manufacturing to counter the volatility and unpredictability of the markets and provide more individualization for customers. However, the design and implementation of flexibility within manufacturing systems are costly and only economically viable if applicable to actual demand fluctuations. To this end, companies are considering additive manufacturing (AM) to make production more flexible. This paper develops a conceptual model for the impact quantification of AM on volume and mix flexibility within production systems in the early stages of the factory-planning process. Together with the model, an application guideline is presented to help planners with the flexibility quantification and the factory design process. Following the development of the model and guideline, a case study is presented to indicate the potential impact additive technologies can have on manufacturing flexibility Within the case study, various scenarios with different production system configurations and production programs are analyzed, and the impact of the additive technologies on volume and mix flexibility is calculated. This work will allow factory planners to determine the potential impacts of AM on manufacturing flexibility in an early planning stage and design their production systems accordingly.
Inhaltsverzeichnis - Bachelorarbeiten
1. Zukunft der Rente – Kann eine Erwerbstätigenversicherung das
demografische Problem nachhaltig lösen?
- Marcel Sept | Seite 4-73
2. Die versammlungsgebundenen Aktionärsrechte in der neuen
virtuellen Hauptversammlung – eine Bewertung aus Unternehmer- und Aktionärssicht
- Christina Zillinger | Seite 74-130
3. Praxisleitfaden für den Arbeitgeber zum gesetzlichen
Sonderkündigungsschutz – Was muss der Arbeitgeber tun, um durch
Gesetz besonders geschützten Arbeitnehmern kündigen zu können?
- Johanna Wiechert | Seite 131-195
4. Die Steuervergünstigung bei Umstrukturierungen im Konzern nach
§ 6a GrEStG im Lichte der aktuellen Rechtsprechung
- Marius Thelen | Seite 196-265
The increasing share of renewable electricity in the grid drives the need for sufficient storage capacity. Especially for seasonal storage, power-to-gas can be a promising approach. Biologically produced methane from hydrogen produced from surplus electricity can be used to substitute natural gas in the existing infrastructure. Current reactor types are not or are poorly optimized for flexible methanation. Therefore, this work proposes a new reactor type with a plug flow reactor (PFR) design. Simulations in COMSOL Multiphysics ® showed promising properties for operation in laminar flow. An experiment was conducted to support the simulation results and to determine the gas fraction of the novel reactor, which was measured to be 29%. Based on these simulations and experimental results, the reactor was constructed as a 14 m long, 50 mm diameter tube with a meandering orientation. Data processing was established, and a step experiment was performed. In addition, a kLa of 1 h−1 was determined. The results revealed that the experimental outcomes of the type of flow and gas fractions are in line with the theoretical simulation. The new design shows promising properties for flexible methanation and will be tested.
§ 1 | Geltungsbereich der Prüfungsordnung
§ 2 | Ziel des Studiums, Zweck der Prüfung, Abschlussgrad
§ 3 | Beginn, Dauer, Umfang und Gliederung des Studiums
§ 4 | Zugang zum Studium, Praktikum
§ 5 | Prüfungsausschuss
§ 6 | Studien- und Prüfungselemente
§ 7 | Zulassung zu den Prüfungen
§ 8 | Durchführung von Prüfungen
§ 9 | Verbesserungsversuch
§ 10 | Anrechnung von Studienzeiten, Studien- und Prüfungsleistungen
§ 11 | Praxissemester
§ 12 | Mobilitätssemester (Auslandssemester)
§ 13 | Bachelorprojekt§ 14 | Gesamtnote, Zeugnis, Bachelorurkunde
§ 15 | Inkrafttreten, Veröffentlichung
Anlage 1 | Studienplan Kernstudium
Anlage 2 | Allgemeine Kompetenzen
Background
Hip fractures are a common and costly health problem, resulting in significant morbidity and mortality, as well as high costs for healthcare systems, especially for the elderly. Implementing surgical preventive strategies has the potential to improve the quality of life and reduce the burden on healthcare resources, particularly in the long term. However, there are currently limited guidelines for standardizing hip fracture prophylaxis practices.
Methods
This study used a cost-effectiveness analysis with a finite-state Markov model and cohort simulation to evaluate the primary and secondary surgical prevention of hip fractures in the elderly. Patients aged 60 to 90 years were simulated in two different models (A and B) to assess prevention at different levels. Model A assumed prophylaxis was performed during the fracture operation on the contralateral side, while Model B included individuals with high fracture risk factors. Costs were obtained from the Centers for Medicare & Medicaid Services, and transition probabilities and health state utilities were derived from available literature. The baseline assumption was a 10% reduction in fracture risk after prophylaxis. A sensitivity analysis was also conducted to assess the reliability and variability of the results.
Results
With a 10% fracture risk reduction, model A costs between $8,850 and $46,940 per quality-adjusted life-year ($/QALY). Additionally, it proved most cost-effective in the age range between 61 and 81 years. The sensitivity analysis established that a reduction of ≥ 2.8% is needed for prophylaxis to be definitely cost-effective. The cost-effectiveness at the secondary prevention level was most sensitive to the cost of the contralateral side’s prophylaxis, the patient’s age, and fracture treatment cost. For high-risk patients with no fracture history, the cost-effectiveness of a preventive strategy depends on their risk profile. In the baseline analysis, the incremental cost-effectiveness ratio at the primary prevention level varied between $11,000/QALY and $74,000/QALY, which is below the defined willingness to pay threshold.
Conclusion
Due to the high cost of hip fracture treatment and its increased morbidity, surgical prophylaxis strategies have demonstrated that they can significantly relieve the healthcare system. Various key assumptions facilitated the modeling, allowing for adequate room for uncertainty. Further research is needed to evaluate health-state-associated risks.
The eVTOL industry is a rapidly growing mass market expected to start in 2024. eVTOL compete, caused by their predicted missions, with ground-based transportation modes, including mainly passenger cars. Therefore, the automotive and classical aircraft design process is reviewed and compared to highlight advantages for eVTOL development. A special focus is on ergonomic comfort and safety. The need for further investigation of eVTOL’s crashworthiness is outlined by, first, specifying the relevance of passive safety via accident statistics and customer perception analysis; second, comparing the current state of regulation and certification; and third, discussing the advantages of integral safety and applying the automotive safety approach for eVTOL development. Integral safety links active and passive safety, while the automotive safety approach means implementing standardized mandatory full-vehicle crash tests for future eVTOL. Subsequently, possible crash impact conditions are analyzed, and three full-vehicle crash load cases are presented.
Obstacle avoidance is critical for unmanned aerial vehicles (UAVs) operating autonomously. Obstacle avoidance algorithms either rely on global environment data or local sensor data. Local path planners react to unforeseen objects and plan purely on local sensor information. Similarly, animals need to find feasible paths based on local information about their surroundings. Therefore, their behavior is a valuable source of inspiration for path planning. Bumblebees tend to fly vertically over far-away obstacles and horizontally around close ones, implying two zones for different flight strategies depending on the distance to obstacles. This work enhances the local path planner 3DVFH* with this bio-inspired strategy. The algorithm alters the goal-driven function of the 3DVFH* to climb-preferring if obstacles are far away. Prior experiments with bumblebees led to two definitions of flight zone limits depending on the distance to obstacles, leading to two algorithm variants. Both variants reduce the probability of not reaching the goal of a 3DVFH* implementation in Matlab/Simulink. The best variant, 3DVFH*b-b, reduces this probability from 70.7 to 18.6% in city-like worlds using a strong vertical evasion strategy. Energy consumption is higher, and flight paths are longer compared to the algorithm version with pronounced horizontal evasion tendency. A parameter study analyzes the effect of different weighting factors in the cost function. The best parameter combination shows a failure probability of 6.9% in city-like worlds and reduces energy consumption by 28%. Our findings demonstrate the potential of bio-inspired approaches for improving the performance of local path planning algorithms for UAV.
The aerodynamic performance of propellers strongly depends on their geometry and, consequently, on aeroelastic deformations. Knowledge of the extent of the impact is crucial for overall aircraft performance. An integrated simulation environment for steady aeroelastic propeller simulations is presented. The simulation environment is applied to determine the impact of elastic deformations on the aerodynamic propeller performance. The aerodynamic module includes a blade element momentum approach to calculate aerodynamic loads. The structural module is based on finite beam elements, according to Timoshenko theory, including moderate deflections. Several fixed-pitch propellers with thin-walled cross sections made of both isotropic and non-isotropic materials are investigated. The essential parameters are varied: diameter, disc loading, sweep, material, rotational, and flight velocity. The relative change of thrust between rigid and elastic blades quantifies the impact of propeller elasticity. Swept propellers of large diameters or low disc loadings can decrease the thrust significantly. High flight velocities and low material stiffness amplify this tendency. Performance calculations without consideration of propeller elasticity can lead to decreased efficiency. To avoid cost- and time-intense redesigns, propeller elasticity should be considered for swept planforms and low disc loadings.
1. Die Wirksamkeitsvoraussetzungen der Verdachtskündigung gegenüber einem Arbeitnehmer - Jana Scheilen | Seite 4-66
2. Besteuerungsinkongruenzen im Internationalen Steuerrecht - die Umsetzung der ATAD II in Form des § 4k EStG in Bezug auf hybride Gesellschaften und Betriebsstätten
- Max Peiffer | Seite 67-126
3. Der Zuzug einer Gesellschaft aus einem Drittstaat nach Deutschland - Herausforderungen durch die modifizierte Sitztheorie und Lösungsmöglichkeiten
- Anna-Luisa Görlich | Seite 127-189
4. Escalation of Commitment und seine Einflussfaktoren in der unternehmerischen Entscheidungsfindung: Ein Szenario-Experiment
- Theresa Hacke | Seite 190-245
Wohlfühlen in den eigenen vier Wänden : ein Produkt, welches die Wohn- und Lebensqualität steigert.
(2023)
Viele Menschen fühlen sich in ihren eigenen vier Wänden nicht wohl. Sie sind gestresst und können nicht entspannen. Ziel dieser Arbeit ist es, ein Produkt zu erschaffen, welches in seinen Funktionen und seinem Design dafür sorgt, dass die Nutzer:innen sich zu Hause wohler fühlen. Es soll alle Funktionen vereinen, die dafür sorgen, dass der Alltagsstress besser bewältigt werden kann und man in seinem Zuhause entspannen kann und den Moment mehr genießt. Entstanden ist Iwa, ein Produkt, welches zum einen als Luftreiniger arbeitet und die Raumluft filtert und im Zusammenspiel mit Licht und Musik die Raumatmosphäre verbessert und so Stress mindert. Das Design soll genau wie die Funktionen beruhigend, entspannend und erdend wirken. Es ist angelehnt am Zen-Design. So bietet Iwa einen großen Mehrwert. Die Funktionen sorgen im Zusammenspiel mit dem Design für eine verbesserte Wohn- und Lebensqualität.
New European Union (EU) regulations for UAS operations require an operational risk analysis, which includes an estimation of the potential danger of the UAS crashing. A key parameter for the potential ground risk is the kinetic impact energy of the UAS. The kinetic energy depends on the impact velocity of the UAS and, therefore, on the aerodynamic drag and the weight during free fall. Hence, estimating the impact energy of a UAS requires an accurate drag estimation of the UAS in that state. The paper at hand presents the aerodynamic drag estimation of small-scale multirotor UAS. Multirotor UAS of various sizes and configurations were analysed with a fully unsteady Reynolds-averaged Navier–Stokes approach. These simulations included different velocities and various fuselage pitch angles of the UAS. The results were compared against force measurements performed in a subsonic wind tunnel and provided good consistency. Furthermore, the influence of the UAS`s fuselage pitch angle as well as the influence of fixed and free spinning propellers on the aerodynamic drag was analysed. Free spinning propellers may increase the drag by up to 110%, depending on the fuselage pitch angle. Increasing the fuselage pitch angle of the UAS lowers the drag by 40% up to 85%, depending on the UAS. The data presented in this paper allow for increased accuracy of ground risk assessments.
In this work, the bioabsorbable materials, namely fibroin, polylactide acid (PLA), magnesium and magnesium oxide are investigated for their application as transient, resistive temperature detectors (RTD). For this purpose, a thin-film magnesium-based meander-like electrode is deposited onto a flexible, bioabsorbable substrate (fibroin or PLA) and encapsulated (passivated) by additional magnesium oxide layers on top and below the magnesium-based electrode. The morphology of different layered RTDs is analyzed by scanning electron microscopy. The sensor performance and lifetime of the RTD is characterized both under ambient atmospheric conditions between 30°C and 43°C, and wet tissue-like conditions with a constant temperature regime of 37°C. The latter triggers the degradation process of the magnesium-based layers. The 3-layers RTDs on a PLA substrate could achieve a lifetime of 8.5 h. These sensors also show the best sensor performance under ambient atmospheric conditions with a mean sensitivity of 0.48 Ω/°C ± 0.01 Ω/°C.
Herein, fibroin, polylactide (PLA), and carbon are investigated for their suitability as biocompatible and biodegradable materials for amperometric biosensors. For this purpose, screen-printed carbon electrodes on the biodegradable substrates fibroin and PLA are modified with a glucose oxidase membrane and then encapsulated with the biocompatible material Ecoflex. The influence of different curing parameters of the carbon electrodes on the resulting biosensor characteristics is studied. The morphology of the electrodes is investigated by scanning electron microscopy, and the biosensor performance is examined by amperometric measurements of glucose (0.5–10 mM) in phosphate buffer solution, pH 7.4, at an applied potential of 1.2 V versus a Ag/AgCl reference electrode. Instead of Ecoflex, fibroin, PLA, and wound adhesive are tested as alternative encapsulation compounds: a series of swelling tests with different fibroin compositions, PLA, and Ecoflex has been performed before characterizing the most promising candidates by chronoamperometry. Therefore, the carbon electrodes are completely covered with the particular encapsulation material. Chronoamperometric measurements with H2O2 concentrations between 0.5 and 10 mM enable studying the leakage current behavior.
Several species of (poly)saccharides and organic acids can be found often simultaneously in various biological matrices, e.g., fruits, plant materials, and biological fluids. The analysis of such matrices sometimes represents a challenging task. Using Aloe vera (A. vera) plant materials as an example, the performance of several spectro-scopic methods (80 MHz benchtop NMR, NIR, ATR-FTIR and UV–vis) for the simultaneous analysis of quality parameters of this plant material was compared. The determined parameters include (poly)saccharides such as aloverose, fructose and glucose as well as organic acids (malic, lactic, citric, isocitric, acetic, fumaric, benzoic and sorbic acids). 500 MHz NMR and high-performance liquid chromatography (HPLC) were used as the reference methods.
UV–vis data can be used only for identification of added preservatives (benzoic and sorbic acids) and drying agent (maltodextrin) and semiquantitative analysis of malic acid. NIR and MIR spectroscopies combined with multivariate regression can deliver more informative overview of A. vera extracts being able to additionally quantify glucose, aloverose, citric, isocitric, malic, lactic acids and fructose. Low-field NMR measurements can be used for the quantification of aloverose, glucose, malic, lactic, acetic, and benzoic acids. The benchtop NMR method was successfully validated in terms of robustness, stability, precision, reproducibility and limit of detection (LOD) and quantification (LOQ), respectively. All spectroscopic techniques are useful for the screening of (poly)saccharides and organic acids in plant extracts and should be applied according to its availability as well as information and confidence required for the specific analytical goal. Benchtop NMR spectroscopy seems to be the most feasible solution for quality control of A. vera products.
With the prevalence of glucosamine- and chondroitin-containing dietary supplements for people with osteoarthritis in the marketplace, it is important to have an accurate and reproducible analytical method for the quantitation of these compounds in finished products. NMR spectroscopic method based both on low- (80 MHz) and high- (500–600 MHz) field NMR instrumentation was established, compared and validated for the determination of chondroitin sulfate and glucosamine in dietary supplements. The proposed method was applied for analysis of 20 different dietary supplements. In the majority of cases, quantification results obtained on the low-field NMR spectrometer are similar to those obtained with high-field 500–600 MHz NMR devices. Validation results in terms of accuracy, precision, reproducibility, limit of detection and recovery demonstrated that the developed method is fit for purpose for the marketed products. The NMR method was extended to the analysis of methylsulfonylmethane, adulterant maltodextrin, acetate and inorganic ions. Low-field NMR can be a quicker and cheaper alternative to more expensive high-field NMR measurements for quality control of the investigated dietary supplements. High-field NMR instrumentation can be more favorable for samples with complex composition due to better resolution, simultaneously giving the possibility of analysis of inorganic species such as potassium and chloride.
The aim of the present study was the characterisation of three true subtilisins and one phylogenetically intermediate subtilisin from halotolerant and halophilic microorganisms. Considering the currently growing enzyme market for efficient and novel biocatalysts, data mining is a promising source for novel, as yet uncharacterised enzymes, especially from halophilic or halotolerant Bacillaceae, which offer great potential to meet industrial needs. Both halophilic bacteria Pontibacillus marinus DSM 16465ᵀ and Alkalibacillus haloalkaliphilus DSM 5271ᵀ and both halotolerant bacteria Metabacillus indicus DSM 16189 and Litchfieldia alkalitelluris DSM 16976ᵀ served as a source for the four new subtilisins SPPM, SPAH, SPMI and SPLA. The protease genes were cloned and expressed in Bacillus subtilis DB104. Purification to apparent homogeneity was achieved by ethanol precipitation, desalting and ion-exchange chromatography. Enzyme activity could be observed between pH 5.0–12.0 with an optimum for SPPM, SPMI and SPLA around pH 9.0 and for SPAH at pH 10.0. The optimal temperature for SPMI and SPLA was 70 °C and for SPPM and SPAH 55 °C and 50 °C, respectively. All proteases showed high stability towards 5% (w/v) SDS and were active even at NaCl concentrations of 5 M. The four proteases demonstrate potential for future biotechnological applications.
Background
Aminoacylases are highly promising enzymes for the green synthesis of acyl-amino acids, potentially replacing the environmentally harmful Schotten-Baumann reaction. Long-chain acyl-amino acids can serve as strong surfactants and emulsifiers, with application in cosmetic industries. Heterologous expression of these enzymes, however, is often hampered, limiting their use in industrial processes.
Results
We identified a novel mycobacterial aminoacylase gene from Mycolicibacterium smegmatis MKD 8, cloned and expressed it in Escherichia coli and Vibrio natriegens using the T7 overexpression system. The recombinant enzyme was prone to aggregate as inclusion bodies, and while V. natriegens Vmax™ could produce soluble aminoacylase upon induction with isopropyl β-d-1-thiogalactopyranoside (IPTG), E. coli BL21 (DE3) needed autoinduction with lactose to produce soluble recombinant protein. We successfully conducted a chaperone co-expression study in both organisms to further enhance aminoacylase production and found that overexpression of chaperones GroEL/S enhanced aminoacylase activity in the cell-free extract 1.8-fold in V. natriegens and E. coli. Eventually, E. coli ArcticExpress™ (DE3), which co-expresses cold-adapted chaperonins Cpn60/10 from Oleispira antarctica, cultivated at 12 °C, rendered the most suitable expression system for this aminoacylase and exhibited twice the aminoacylase activity in the cell-free extract compared to E. coli BL21 (DE3) with GroEL/S co-expression at 20 °C. The purified aminoacylase was characterized based on hydrolytic activities, being most stable and active at pH 7.0, with a maximum activity at 70 °C, and stability at 40 °C and pH 7.0 for 5 days. The aminoacylase strongly prefers short-chain acyl-amino acids with smaller, hydrophobic amino acid residues. Several long-chain amino acids were fairly accepted in hydrolysis as well, especially N-lauroyl-L-methionine. To initially evaluate the relevance of this aminoacylase for the synthesis of N-acyl-amino acids, we demonstrated that lauroyl-methionine can be synthesized from lauric acid and methionine in an aqueous system.
Conclusion
Our results suggest that the recombinant enzyme is well suited for synthesis reactions and will thus be further investigated.