TY - JOUR A1 - Capitain, Charlotte A1 - Ross-Jones, Jesse A1 - Möhring, Sophie A1 - Tippkötter, Nils T1 - Differential scanning calorimetry for quantification of polymer biodegradability in compost JF - International Biodeterioration & Biodegradation N2 - The objective of this study is the establishment of a differential scanning calorimetry (DSC) based method for online analysis of the biodegradation of polymers in complex environments. Structural changes during biodegradation, such as an increase in brittleness or crystallinity, can be detected by carefully observing characteristic changes in DSC profiles. Until now, DSC profiles have not been used to draw quantitative conclusions about biodegradation. A new method is presented for quantifying the biodegradation using DSC data, whereby the results were validated using two reference methods. The proposed method is applied to evaluate the biodegradation of three polymeric biomaterials: polyhydroxybutyrate (PHB), cellulose acetate (CA) and Organosolv lignin. The method is suitable for the precise quantification of the biodegradability of PHB. For CA and lignin, conclusions regarding their biodegradation can be drawn with lower resolutions. The proposed method is also able to quantify the biodegradation of blends or composite materials, which differentiates it from commonly used degradation detection methods. Y1 - 2020 U6 - http://dx.doi.org/10.1016/j.ibiod.2020.104914 SN - 0964-8305 VL - 149 SP - In Press, Article number 104914 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Muschallik, Lukas A1 - Molinnus, Denise A1 - Jablonski, Melanie A1 - Kipp, Carina Ronja A1 - Bongaerts, Johannes A1 - Pohl, Martina A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Selmer, Thorsten A1 - Siegert, Petra T1 - Synthesis of α-hydroxy ketones and vicinal (R, R)-diols by Bacillus clausii DSM 8716ᵀ butanediol dehydrogenase JF - RSC Advances N2 - α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated. Y1 - 2020 U6 - http://dx.doi.org/10.1039/D0RA02066D SN - 2046-2069 VL - 10 SP - 12206 EP - 12216 PB - Royal Society of Chemistry (RSC) CY - Cambridge ER - TY - JOUR A1 - Wardoyo, Arinto Y.P. A1 - Noor, Johan A.E. A1 - Elbers, Gereon A1 - Schmitz, Sandra A1 - Flaig, Sascha T. A1 - Budianto, Arif T1 - Characterizing volcanic ash elements from the 2015 eruptions of bromo and raung volcanoes, Indonesia JF - Polish Journal of Environmental Studies N2 - The volcanic eruptions of Mt. Bromo and Mt. Raung in East Java, Indonesia, in 2015 perturbed volcanic materials and affected surface-layer air quality at surrounding locations. During the episodes, the volcanic ash from the eruptions influenced visibility, traffic accidents, flight schedules, and human health. In this research, the volcanic ash particles were collected and characterized by relying on the detail of physical observation. We performed an assessment of the volcanic ash elements to characterize the volcanic ash using two different methods which are aqua regia extracts followed by MP-AES and XRF laboratory test of bulk samples. The analysis results showed that the volcanic ash was mixed of many materials, such as Al, Si, P, K, Ca, Ti, V, Cr, Mn, Fe, Ni, and others. Fe, Si, Ca, and Al were found as the major elements, while the others were the trace elements Ba, Cr, Cu, Mn, P, Mn, Ni, Zn, Sb, Sr, and V with the minor concentrations. XRF analyses showed that Fe dominated the elements of the volcanic ash. The XRF analysis showed that Fe was at 35.40% in Bromo and 43.00% in Raung of the detected elements in bulk material. The results of aqua regia extracts analyzed by MP-AES were 1.80% and 1.70% of Fe element for Bromo and Raung volcanoes, respectively. Y1 - 2020 U6 - http://dx.doi.org/10.15244/pjoes/99101 SN - 2083-5906 VL - 29 IS - 2 SP - 1899 EP - 1907 PB - HARD CY - Olsztyn ER - TY - JOUR A1 - Eckert, Alexander A1 - Abbasi, Mozhdeh A1 - Mang, Thomas A1 - Saalwächter, Kay A1 - Walther, Andreas T1 - Structure, Mechanical Properties, and Dynamics of Polyethylenoxide/Nanoclay Nacre-Mimetic Nanocomposites JF - Macromolecules N2 - Nacre-mimetic nanocomposites based on high fractions of synthetic high-aspect-ratio nanoclays in combination with polymers are continuously pushing boundaries for advanced material properties, such as high barrier against oxygen, extraordinary mechanical behavior, fire shielding, and glass-like transparency. Additionally, they provide interesting model systems to study polymers under nanoconfinement due to the well-defined layered nanocomposite arrangement. Although the general behavior in terms of forming such layered nanocomposite materials using evaporative self-assembly and controlling the nanoclay gallery spacing by the nanoclay/polymer ratio is understood, some combinations of polymer matrices and nanoclay reinforcement do not comply with the established models. Here, we demonstrate a thorough characterization and analysis of such an unusual polymer/nanoclay pair that falls outside of the general behavior. Poly(ethylene oxide) (PEO) and sodium fluorohectorite form nacre-mimetic, lamellar nanocomposites that are completely transparent and show high mechanical stiffness and high gas barrier, but there is only limited expansion of the nanoclay gallery spacing when adding increasing amounts of polymer. This behavior is maintained for molecular weights of PEO varied over four orders of magnitude and can be traced back to depletion forces. By careful investigation via X-ray diffraction and proton low-resolution solid-state NMR, we are able to quantify the amount of mobile and immobilized polymer species in between the nanoclay galleries and around proposed tactoid stacks embedded in a PEO matrix. We further elucidate the unusual confined polymer dynamics, indicating a relevant role of specific surface interactions. Y1 - 2020 U6 - http://dx.doi.org/10.1021/acs.macromol.9b01931 SN - 1520-5835 VL - 53 IS - 5 SP - 1716 EP - 1725 PB - ACS Publications CY - Washington, DC ER - TY - JOUR A1 - Welden, Rene A1 - Jablonski, Melanie A1 - Wege, Christina A1 - Keusgen, Michael A1 - Wagner, Patrick Hermann A1 - Wagner, Torsten A1 - Schöning, Michael Josef T1 - Light-Addressable Actuator-Sensor Platform for Monitoring and Manipulation of pH Gradients in Microfluidics: A Case Study with the Enzyme Penicillinase JF - Biosensors N2 - The feasibility of light-addressed detection and manipulation of pH gradients inside an electrochemical microfluidic cell was studied. Local pH changes, induced by a light-addressable electrode (LAE), were detected using a light-addressable potentiometric sensor (LAPS) with different measurement modes representing an actuator-sensor system. Biosensor functionality was examined depending on locally induced pH gradients with the help of the model enzyme penicillinase, which had been immobilized in the microfluidic channel. The surface morphology of the LAE and enzyme-functionalized LAPS was studied by scanning electron microscopy. Furthermore, the penicillin sensitivity of the LAPS inside the microfluidic channel was determined with regard to the analyte’s pH influence on the enzymatic reaction rate. In a final experiment, the LAE-controlled pH inhibition of the enzyme activity was monitored by the LAPS. KW - microfluidics KW - enzyme kinetics KW - actuator-sensor system KW - light-addressable electrode KW - light-addressable potentiometric sensor Y1 - 2021 U6 - http://dx.doi.org/10.3390/bios11060171 SN - 2079-6374 N1 - This article belongs to the Special Issue "Selected Papers from the 1st International Electronic Conference on Biosensors (IECB 2020)" VL - 11 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Capitain, Charlotte A1 - Wagner, Sebastian A1 - Hummel, Joana A1 - Tippkötter, Nils T1 - Investigation of C–N Formation Between Catechols and Chitosan for the Formation of a Strong, Novel Adhesive Mimicking Mussel Adhesion JF - Waste and Biomass Valorization Y1 - 2021 U6 - http://dx.doi.org/10.1007/s12649-020-01110-5 SN - 1877-265X N1 - Corresponding author: Nils Tippkötter VL - 12 SP - 1761 EP - 1779 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Monakhova, Yulia A1 - Diehl, Bernd W.K. T1 - Novel approach of qNMR workflow by standardization using 2H integral: Application to any intrinsic calibration standard JF - Talanta N2 - Quantitative nuclear magnetic resonance (qNMR) is routinely performed by the internal or external standardization. The manuscript describes a simple alternative to these common workflows by using NMR signal of another active nuclei of calibration compound. For example, for any arbitrary compound quantification by NMR can be based on the use of an indirect concentration referencing that relies on a solvent having both 1H and 2H signals. To perform high-quality quantification, the deuteration level of the utilized deuterated solvent has to be estimated. In this contribution the new method was applied to the determination of deuteration levels in different deuterated solvents (MeOD, ACN, CDCl3, acetone, benzene, DMSO-d6). Isopropanol-d6, which contains a defined number of deuterons and protons, was used for standardization. Validation characteristics (precision, accuracy, robustness) were calculated and the results showed that the method can be used in routine practice. Uncertainty budget was also evaluated. In general, this novel approach, using standardization by 2H integral, benefits from reduced sample preparation steps and uncertainties, and can be applied in different application areas (purity determination, forensics, pharmaceutical analysis, etc.). KW - qNMR KW - Deuterium NMR KW - Deuterated solvents KW - Standardization Y1 - 2021 SN - 0039-9140 U6 - http://dx.doi.org/10.1016/j.talanta.2020.121504 VL - 222 IS - Article number: 121504 PB - Elsevier ER - TY - JOUR A1 - Burmistrova, Natalia A. A1 - Soboleva, Polina M. A1 - Monakhova, Yulia T1 - Is infrared spectroscopy combined with multivariate analysis a promising tool for heparin authentication? JF - Journal of Pharmaceutical and Biomedical Analysis N2 - The investigation of the possibility to determine various characteristics of powder heparin (n = 115) was carried out with infrared spectroscopy. The evaluation of heparin samples included several parameters such as purity grade, distributing company, animal source as well as heparin species (i.e. Na-heparin, Ca-heparin, and heparinoids). Multivariate analysis using principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), and partial least squares – discriminant analysis (PLS-DA) were applied for the modelling of spectral data. Different pre-processing methods were applied to IR spectral data; multiplicative scatter correction (MSC) was chosen as the most relevant. Obtained results were confirmed by nuclear magnetic resonance (NMR) spectroscopy. Good predictive ability of this approach demonstrates the potential of IR spectroscopy and chemometrics for screening of heparin quality. This approach, however, is designed as a screening tool and is not considered as a replacement for either of the methods required by USP and FDA. KW - IR spectroscopy KW - Heparin KW - Authenticity KW - Principal component analysis KW - Soft independent modeling of class analogy Y1 - 2021 SN - 0731-7085 U6 - http://dx.doi.org/10.1016/j.jpba.2020.113811 VL - 194 IS - Article number: 113811 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Monakhova, Yulia A1 - Diehl, Bernd W. K. T1 - Simplification of NMR Workflows by Standardization Using 2H Integral of Deuterated Solvent as Applied to Aloe vera Preparations JF - Applied Magnetic Resonance N2 - In this study, a recently proposed NMR standardization approach by 2H integral of deuterated solvent for quantitative multicomponent analysis of complex mixtures is presented. As a proof of principle, the existing NMR routine for the analysis of Aloe vera products was modified. Instead of using absolute integrals of targeted compounds and internal standard (nicotinamide) from 1H-NMR spectra, quantification was performed based on the ratio of a particular 1H-NMR compound integral and 2H-NMR signal of deuterated solvent D2O. Validation characteristics (linearity, repeatability, accuracy) were evaluated and the results showed that the method has the same precision as internal standardization in case of multicomponent screening. Moreover, a dehydration process by freeze drying is not necessary for the new routine. Now, our NMR profiling of A. vera products needs only limited sample preparation and data processing. The new standardization methodology provides an appealing alternative for multicomponent NMR screening. In general, this novel approach, using standardization by 2H integral, benefits from reduced sample preparation steps and uncertainties, and is recommended in different application areas (purity determination, forensics, pharmaceutical analysis, etc.). Y1 - 2021 U6 - http://dx.doi.org/10.1007/s00723-021-01393-4 SN - 1613-7507 VL - 52 IS - 11 SP - 1591 EP - 1600 PB - Springer CY - Cham ER - TY - JOUR A1 - Burger, René A1 - Rumpf, Jessica A1 - Do, Xuan Tung A1 - Monakhova, Yulia A1 - Diehl, Bernd W. K. A1 - Rehahn, Matthias A1 - Schulze, Margit T1 - Is NMR combined with multivariate regression applicable for the molecular weight determination of randomly cross-linked polymers such as lignin? JF - ACS Omega N2 - The molecular weight properties of lignins are one of the key elements that need to be analyzed for a successful industrial application of these promising biopolymers. In this study, the use of 1H NMR as well as diffusion-ordered spectroscopy (DOSY NMR), combined with multivariate regression methods, was investigated for the determination of the molecular weight (Mw and Mn) and the polydispersity of organosolv lignins (n = 53, Miscanthus x giganteus, Paulownia tomentosa, and Silphium perfoliatum). The suitability of the models was demonstrated by cross validation (CV) as well as by an independent validation set of samples from different biomass origins (beech wood and wheat straw). CV errors of ca. 7–9 and 14–16% were achieved for all parameters with the models from the 1H NMR spectra and the DOSY NMR data, respectively. The prediction errors for the validation samples were in a similar range for the partial least squares model from the 1H NMR data and for a multiple linear regression using the DOSY NMR data. The results indicate the usefulness of NMR measurements combined with multivariate regression methods as a potential alternative to more time-consuming methods such as gel permeation chromatography. Y1 - 2021 U6 - http://dx.doi.org/10.1021/acsomega.1c03574 SN - 2470-1343 VL - 6 IS - 44 SP - 29516 EP - 29524 PB - ACS Publications CY - Washington, DC ER -