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- ItemBatch and continuous lactic acid fermentation based on a multi-substrate approach(Basel : MDPI AG, 2020) Olszewska-Widdrat, Agata; Alexandri, Maria; López-Gómez, José Pablo; Schneider, Roland; Venus, JoachimThe utilisation of waste materials and industrial residues became a priority within the bioeconomy concept and the production of biobased chemicals. The aim of this study was to evaluate the feasibility to continuously produce L-lactic acid from different renewable substrates, in a multi-substrate strategy mode. Based on batch experiments observations, Bacillus coagulans A534 strain was able to continuously metabolise acid whey, sugar beet molasses, sugar bread, alfalfa press green juice and tapioca starch. Additionally, reference experiments showed its behaviour in standard medium. Continuous fermentations indicated that the highest productivity was achieved when molasses was employed with a value of 10.34 g·L−1·h−1, while the lactic acid to sugar conversion yield was 0.86 g·g−1 . This study demonstrated that LA can be efficiently produced in continuous mode regardless the substrate, which is a huge advantage in comparison to other platform chemicals. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemTunable nano-replication to explore the omniphobic characteristics of springtail skin(London : Macmillan Publishers, 2013) Hensel, R.; Helbig, R.; Aland, S.; Voigt, A.; Neinhuis, C.; Werner, C.Springtails (Collembola) are wingless arthropods adapted to cutaneous respiration in temporarily rain-flooded and microbially contaminated habitats by a non-wetting and antiadhesive skin surface that is mechanically rather stable. Recapitulating the robust and effectively repellent surface characteristics of springtail skin in engineered materials may offer exciting opportunities for demanding applications, but it requires a detailed understanding of the underlying design principles. Towards this aim and based on our recent analysis of the structural features of springtail skin, we developed a tunable polymer replication process to dissect the contributions of different structural elements and surface chemistry to the omniphobic performance of the cuticle. The Cassie-Wenzel transition at elevated pressures was explored by in situ plastron collapse experiments and by numerical FEM simulations. The results obtained unravel the decisive role of nanoscopic cuticle structures for the protection of springtails against wetting, and explain how the evolved nanotopography enables the production of omniphobic surfaces even from intrinsically hydrophilic polymer materials.
- ItemEffect of fluoride mouthrinses and stannous ions on the erosion protective properties of the in situ pellicle(Berlin : Springer Nature, 2019) Kensche, A.; Buschbeck, E.; König, B.; Koch, M.; Kirsch, J.; Hannig, C.; Hannig, M.The particular feature of this study is the investigation of effects of pure fluoride- or stannous ions based mouthrinses on the erosion protective properties and the ultrastructure of the in situ pellicle (12 volunteers). Experimental solutions were prepared either from 500 ppm NaF, SMFP, AmF or SnF 2 or 1563 ppm SnCl 2 , respectively. After 1 min of in situ pellicle formation on bovine enamel slabs, rinses with one of the preparations were performed for 1 min and intraoral specimens’ exposure was continued for 28 min. Native enamel slabs and rinses with bidestilled water served as controls. After oral exposure, slabs were incubated in HCl (pH 2; 2.3; 3) for 120 s and kinetics of calcium- and phosphate release were measured photometrically; representative samples were analysed by TEM and EDX. All mouthrinses reduced mineral loss compared to the native 30-min pellicle. The effect was pH-dependent and significant at all pH values only for the tin-containing mouthrinses. No significant differences were observed between the SnF 2 - and the SnCl 2 -containing solutions. TEM/EDX confirmed ultrastructural pellicle modifications. SnF 2 appears to be the most effective type of fluoride to prevent erosive enamel demineralisation. The observed effects primarily have to be attributed to the stannous ions’ content. © 2019, The Author(s).
- ItemSeparation, characterization, and handling of microalgae by dielectrophoresis(Basel : MDPI, 2020) Abt, Vinzenz; Gringel, Fabian; Han, Arum; Neubauer, Peter; Birkholz, MarioMicroalgae biotechnology has a high potential for sustainable bioproduction of diverse highvalue biomolecules. Some of the main bottlenecks in cell-based bioproduction, and more specifically in microalgae-based bioproduction, are due to insufficient methods for rapid and efficient cell characterization, which contributes to having only a few industrially established microalgal species in commercial use. Dielectrophoresis-based microfluidic devices have been long established as promising tools for label-free handling, characterization, and separation of broad ranges of cells. The technique is based on differences in dielectric properties and sizes, which results in different degrees of cell movement under an applied inhomogeneous electrical field. The method has also earned interest for separating microalgae based on their intrinsic properties, since their dielectric properties may significantly change during bioproduction, in particular for lipid-producing species. Here, we provide a comprehensive review of dielectrophoresis-based microfluidic devices that are used for handling, characterization, and separation of microalgae. Additionally, we provide a perspective on related areas of research in cell-based bioproduction that can benefit from dielectrophoresis-based microdevices. This work provides key information that will be useful for microalgae researchers to decide whether dielectrophoresis and which method is most suitable for their particular application. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemDegradation Kinetics of Lignocellulolytic Enzymes in a Biogas Reactor Using Quantitative Mass Spectrometry(Basel : MDPI, 2023) Küchler, Jan; Willenbücher, Katharina; Reiß, Elisabeth; Nuß, Lea; Conrady, Marius; Ramm, Patrice; Schimpf, Ulrike; Reichl, Udo; Szewzyk, Ulrich; Benndorf, DirkThe supplementation of lignocellulose-degrading enzymes can be used to enhance the performance of biogas production in industrial biogas plants. Since the structural stability of these enzyme preparations is essential for efficient application, reliable methods for the assessment of enzyme stability are crucial. Here, a mass-spectrometric-based assay was established to monitor the structural stability of enzymes, i.e., the structural integrity of these proteins, in anaerobic digestion (AD). The analysis of extracts of Lentinula edodes revealed the rapid degradation of lignocellulose-degrading enzymes, with an approximate half-life of 1.5 h. The observed low structural stability of lignocellulose-degrading enzymes in AD corresponded with previous results obtained for biogas content. The established workflow can be easily adapted for the monitoring of other enzyme formulations and provides a platform for evaluating the effects of enzyme additions in AD, together with a characterization of the biochemical methane potential used in order to determine the biodegradability of organic substrates.
- ItemGround reaction forces and external hip joint moments predict in vivo hip contact forces during gait(Amsterdam [u.a.] : Elsevier Science, 2022) Alves, Sónia A.; Polzehl, Jörg; Brisson, Nicholas M.; Bender, Alwina; Agres, Alison N.; Damm, Philipp; Duda, Georg N.Younger patients increasingly receive total hip arthroplasty (THA) as therapy for end-stage osteoarthritis. To maintain the long-term success of THA in such patients, avoiding extremely high hip loads, i.e., in vivo hip contact force (HCF), is considered essential. However, in vivo HCFs are difficult to determine and their direct measurement is limited to instrumented joint implants. It remains unclear whether external measurements of ground reaction forces (GRFs), a non-invasive, markerless and clinic-friendly measure can estimate in vivo HCFs. Using data from eight patients with instrumented hip implants, this study determined whether GRF time series data, alone or combined with other scalar variables such as hip joint moments (HJMs) and lean muscle volume (LMV), could predict the resultant HCF (rHCF) impulse using a functional linear modeling approach. Overall, single GRF time series data did not predict in vivo rHCF impulses. However, when GRF time series data were combined with LMV of the gluteus medius or sagittal HJM using a functional linear modeling approach, the in vivo rHCF impulse could be predicted from external measures only. Accordingly, this approach can predict in vivo rHCF impulses, and thus provide patients with useful insight regarding their gait behavior to avoid hip joint overloading.
- ItemInfluence of redox stress on crosstalk between fibroblasts and keratinocytes(Basel : MDPI, 2021) Bhartiya, Pradeep; Masur, Kai; Shome, Debarati; Kaushik, Neha; Nguyen, Linh N.; Kaushik, Nagendra Kumar; Choi, Eun HaAlthough the skin is constantly subjected to endogenous and exogenous stress, it maintains a homeostatic state through wound repair and regeneration pathways. Treatment for skin diseases and injury requires a significant understanding of the various mechanisms and interactions that occur within skin cells. Keratinocytes and fibroblasts interact with each other and act as key players in the repair process. Although fibroblasts and keratinocytes are widely studied in wound healing and skin remodeling under different conditions, the influence of redox stress on keratinocyte-fibroblast crosstalk has not been thoroughly investigated. In this study, we used cold atmospheric plasma (CAP) to generate and deliver oxidative stress to keratinocytes and fibroblasts and to assess its impact on their interactions. To this end, we used a well-established in vitro 3D co-culture model imitating a realistic scenario. Our study shows that low CAP exposure is biocompatible and does not affect the viability or energetics of fibroblasts and keratinocytes. Exposure to low doses of CAP enhanced the proliferation rate of cells and stimulated the expression of key genes (KGF, MMP2, GMCSF, IL-6, and IL-8) in fibroblasts, indicating the activation and initiation of the skin repair process. Additionally, enhanced migration was observed under co-culture conditions under the given redox stress conditions, and expression of the upstream regulator and the effectors of the Hippo pathway (YAP and CYR61, respectively), which are associated with enhanced migration, were elevated. Overall, this study reinforces the application of CAP and redox stress in skin repair physiology.
- ItemFlow Cytometric Assessment of the Morphological and Physiological Changes of Listeria monocytogenes and Escherichia coli in Response to Natural Antimicrobial Exposure(Lausanne : Frontiers Media, 2018-11-14) Braschi, Giacomo; Patrignani, Francesca; Siroli, Lorenzo; Lanciotti, Rosalba; Schlueter, Oliver; Froehling, AntjeEssential oils (EOs) or their components represent one of the most promising natural, safe, and feasible alternatives to prevent the growth of food-borne pathogens like Listeria monocytogenes and Escherichia coli in food matrices. Although antimicrobial properties of EOs and their components are well-documented, limited and fragmented information is available on the changes induced by these compounds, even at sub-lethal concentrations, in the physiological properties of microbial cells. The aim of this study was to explore the morpho-physiological changes of L. monocytogenes Scott A and E. coli MG 1655 induced after 1 h exposure to different sub-lethal and lethal concentrations of citral, carvacrol, (E)-2-hexenal, and thyme EO. For this purpose, different cell viability parameters such as membrane integrity, esterase activity, and cytoplasmic cell membrane potential were measured by flow cytometry. Flow cytometric data revealed specific response patterns in relation to the strain, the natural antimicrobial and its concentrations. Both the target microbial strains showed an increased cell membrane permeabilization without a loss of esterase activity and cell membrane potential with increasing citral, carvacrol and thyme EO concentrations. By contrast, (E)-2-hexenal did not significantly affect the measured physiological properties of L. monocytogenes Scott A and E. coli MG 1655. The used approach allowed identifying the most effective natural antimicrobials in relation to the microbial target. Copyright © 2018 Braschi, Patrignani, Siroli, Lanciotti, Schlueter and Froehling.
- ItemConsensusPrime—A Bioinformatic Pipeline for Ideal Consensus Primer Design(Basel : MDPI, 2022) Collatz, Maximilian; Braun, Sascha D.; Monecke, Stefan; Ehricht, RalfBackground: High-quality oligonucleotides for molecular amplification and detection procedures of diverse target sequences depend on sequence homology. Processing input sequences and identifying homogeneous regions in alignments can be carried out by hand only if they are small and contain sequences of high similarity. Finding the best regions for large and inhomogeneous alignments needs to be automated. Results: The ConsensusPrime pipeline was developed to sort out redundant and technical interfering data in multiple sequence alignments and detect the most homologous regions from multiple sequences. It automates the prediction of optimal consensus primers for molecular analytical and sequence-based procedures/assays. Conclusion: ConsensusPrime is a fast and easy-to-use pipeline for predicting optimal consensus primers that is executable on local systems without depending on external resources and web services. An implementation in a Docker image ensures platform-independent executability and installability despite the combination of multiple programs. The source code and installation instructions are publicly available on GitHub.
- ItemMolecular monitoring of the poplar wood chip microbiome as a function of storage strategy(Barking : Elsevier, 2021) Zöhrer, Julia; Probst, Maraike; Dumfort, Sabrina; Lenz, Hannes; Pecenka, Ralf; Insam, Heribert; Ascher-Jenull, JudithOne of the most challenging aspects of using wood chips as renewable energy source is the loss of biomass related to storage. Therefore, we installed three outdoor industrial-scale piles (250 m³) of poplar wood chips and monitored the bacterial and fungal communities by next-generation sequencing over a storage period of 120 d. Two of the three piles were supplemented with calcium dihydroxide (Ca(OH)2) (1.5%, 3% w/w) in order to test its potential as alkaline stabilization agent to preserve woody biomass during storage. Shifts in the microbial community composition occurred almost entirely in the beginning of the storage experiment, which we attribute to the temperature rise of up to 60 °C within the first week of storage. Later, however, we found little changes. Independent of Ca(OH)2 concentration, a consortium of lignocellulolytic and thermotolerant microorganisms dominated the stored wood chip microbiota emphasizing their role as key players during wood decomposition. Although the addition of Ca(OH)2 altered the physicochemical properties of wood chips, it did not prevent loss of biomass. Especially the pH was increased in Ca(OH)2 treated piles. However, only minor differences in the microbial communities’ composition were detected following Ca(OH)2 addition, highlighting the microbes tolerance towards and adaptation to changing environmental conditions.