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How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters

This movie shows how an atmospheric pressure plasma torch can be ignited by microwave power with no additional igniters. After ignition of the plasma, a ...

Renewable resources will be an increasingly important issue for the chemical industry in the future. In the context of white biotechnology, they represent the intersection point of agriculture and the chemical industry. The scarcity and related increase in the price of fossil resources make renewable resources an interesting alternative. If one considers the production of bulk chemicals, it is evident that for this area besides the C sources, sugar and starch, new sources of raw materials must be opened up. One possible solution is to utilize lignocellulose both for materials and energy. This article discusses this interesting prospective for the future, particularly from the point of view of the German industry.

The utilization of renewable resources in German industrial production.

Co-cultivation was a potential strategy in lignocellulolytic biodegradation with producing high activity enzymes due to their synergistic action. The objective of this study was to investigate the rarely understood effects of co-culturing of two white-rot fungi on lignin-modifying enzymes (LMEs) production. Six species, Bjerkandera adusta, Phlebia radiata, Pleurotus ostreatus, Dichomitus squalens, Hypoxylon fragiforme and Pleurotus eryngii, were cultured in pairs to study the production of LMEs. The paired hyphal interaction observed showed that P. eryngii is not suitable for co-growth. The use of agar plates containing dye RBBR showed elevated decolourisation at the confrontation zone between mycelia. Laccase was significantly stimulated only in the co-culture of P. radiata with D. squalens under submerged cultivation; the highest value was measured after 4 days of incubation (120 U mg(-1)). The improved productions of MnP and LiP were simultaneously observed at the co-culture of P. ostreatus and P. radiata (MnP = 800 nkat L(-1) after 4 days of incubation; LiP = 60 nkat L(-1) after 7 days of incubation), though it was not a good producer of laccase. P. ostreatus appeared to possess specific potential to be used in co-cultured production of LMEs. The phenotype of LMEs production was not only dependent on the species used but also regulated by different nutritions available in the culture medium. The present data will provide evidence for illustrating the regulatory roles of C/N on LMEs production under the co-cultures' circumstances.

Co-cultured production of lignin-modifying enzymes with white-rot fungi.

Noninvasive monitoring of tissue-engineered (TE) constructs during their in vitro maturation or postimplantation in vivo is highly relevant for graft evaluation. However, traditional methods for studying cell and matrix components in engineered tissues such as histology, immunohistochemistry, or biochemistry require invasive tissue processing, resulting in the need to sacrifice of TE constructs. Raman spectroscopy offers the unique possibility to analyze living cells label-free in situ and in vivo solely based on their phenotype-specific biochemical fingerprint. In this study, we aimed to determine the applicability of Raman spectroscopy for the noninvasive identification and spectral separation of primary human skin fibroblasts, keratinocytes, and melanocytes, as well as immortalized keratinocytes (HaCaT cells). Multivariate analysis of cell-type-specific Raman spectra enabled the discrimination between living primary and immortalized keratinocytes. We further noninvasively distinguished between fibroblasts, keratinocytes, and melanocytes. Our findings are especially relevant for the engineering of in vitro skin models and for the production of artificial skin, where both the biopsy and the transplant consist of several cell types. To realize a reproducible quality of TE skin, the determination of the purity of the cell populations as well as the detection of potential molecular changes are important. We conclude therefore that Raman spectroscopy is a suitable tool for the noninvasive in situ quality control of cells used in skin tissue engineering applications.

Raman spectroscopy: a noninvasive analysis tool for the discrimination of human skin cells.

A bacterial strain named IGB-41(T) was isolated from a soil sample from an ant hill near Stuttgart, Germany. The strain was Gram-negative, rod-shaped, motile and facultatively anaerobic. Phylogenetic analysis based on 16S rRNA grouped the strain IGB-41(T) within the class Betaproteobacteria into the family Neisseriaceae together with Silvimonas amylolytica NBRC 103189(T), Silvimonas iriomotensis NBRC 103188(T) and Silvimonas terrae KM-45(T) as the closest relatives with sequence similarities of 96.7, 96.6 and 96.1 %, respectively. The G+C content of the genomic DNA was determined to be 61.5 mol% and quinone analysis revealed Q-8 as the only detectable quinone. Major cellular fatty acids were identified as C(16 : 0), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c) and C(18 : 1)ω7c . Strain IGB-41(T) was unique in harbouring phosphoaminolipids, aminolipids and glycoaminolipids when compared with Silvimonas amylolytica NBRC 103189(T) in polar lipid analysis. On the basis of the physiological, phenotypic and genotypic characteristics of strain IGB-41(T), we suggest that the novel strain should be assigned to a new genus Amantichitinum and novel species Amantichitinum ursilacus. The type species of the genus Amantichitinum is Amantichitinum ursilacus and the type strain is IGB-41(T) (=DSM 23761(T) =CIP 110167(T)).

Amantichitinum ursilacus gen. nov., sp. nov., a chitin-degrading bacterium isolated from soil.

Gelatin is a very promising matrix material for in vitro cell culture and tissue engineering, e.g. due to its native RGD content. For the generation of medical soft tissue implants chemical modification of gelatin improves the mechanical properties of gelatin hydrogels and the viscous behavior of gelatin solutions for liquid handling. We present a systematic study on the influence of high degrees of methacrylation on the properties of gelatin solutions and photo-chemically crosslinked hydrogels. Changes from shear thinning to shear thickening behavior of gelatin solutions were observed depending on mass fraction and degree of methacrylation. Degrees of swelling of crosslinked hydrogels ranged from 194 to 770Â % and storage moduli G' from 368 to 5Â kPa, comparable to various natural tissues including several types of cartilage. Crosslinked gels proofed to be cytocompatible according to extract testings based on DIN ISO 10933-5 and in contact with porcine chondrocytes.

Stiff gelatin hydrogels can be photo-chemically synthesized from low viscous gelatin solutions using molecularly functionalized gelatin with a high degree of methacrylation.

Gelatine ist ein sehr vielversprechender Matrixmaterial f&uuml;r in-vitro Zellkultur und Tissue Engineering, z.B. wegen seiner nativen RGD-Inhalt. F&uuml;r die Generation der medizinischen Weichgewebe verbessert Implantate chemische Modifikation von Gelatine die mechanischen Eigenschaften der Gelatine Hydrogele und das Viskose Verhalten von Gelatine-L&ouml;sungen f&uuml;r liquid Handling. Wir pr&auml;sentieren eine systematische Studie &uuml;ber den Einfluss der hohen Grad der Methacrylation auf die Eigenschaften der Gelatine-L&ouml;sungen und Foto-chemisch vernetzte Hydrogele. &Auml;nderungen aus Scherung Ausd&uuml;nnung Verdickung Verhalten von Gelatine-L&ouml;sungen verbogen wurden je nach Massenanteil und Grad der Methacrylation beobachtet. Grad der Schwellung der vernetzte Hydrogele reichten von 194 bis 770 % und Lagerung Moduli G&#39; von 368 bis 5 kPa, vergleichbar mit verschiedenen nat&uuml;rlichen Gewebe, einschlie&szlig;lich verschiedene Arten von Knorpel. Vernetzte Gele schallisoliert Cytocompatible nach Auszug Testings basierend auf DIN ISO 10933-5 und im Kontakt mit Schweinen Chondrozyten zu sein.

Steif Gelatine Hydrogele kann von niedrig viskosen Gelatine-L&ouml;sungen, die ein hohes Ma&szlig; an Methacrylation molekular funktionalisierten Gelatine mit Foto-chemisch synthetisiert werden.

The control of surface properties is a substantial step in the development and improvement of biomaterials for clinical applications as well as for their use in tissue engineering. Interaction of the substrate surface with the biochemical or biological environment is crucial for the outcome of the applied biomaterial and therefore should meet specific requirements regarding the chemical composition, wettability, elasticity, and charge. In this study, we examined the effect of chemical groups introduced by low pressure plasma treatments of polystyrene surfaces on the cell behavior of primary human mesenchymal stem cells (hMSCs) and dermal microvascular endothelial cells (hDMECs). X-ray photoelectron spectroscopy analysis and contact angle measurements were employed to evaluate ammonia-, carbon dioxide-, and acrylic acid-plasma modifications to substrate surfaces. HMSCs and hDMECs were analyzed simultaneously to identify the most suitable surface functionalization for each cell type. Significantly higher cell proliferation was detected on ammonia plasma-treated surfaces. Cell-material interaction could be shown on all created interfaces as well as the expression of typical cell markers. Hence, the applied plasma treatment presents a suitable tool to improve culture condition on polystyrene for two important cell types (hMSCs and hDMECs) in the field of tissue engineering.

Ammonia plasma treatment of polystyrene surfaces enhances proliferation of primary human mesenchymal stem cells and human endothelial cells.

In this work, an enzyme catalyzed detoxification process of lignocellulose hydrolyzates with immobilized laccase from Trametes versicolor was developed and optimized. Further, the immobilized laccase significantly reduced the amount of toxic phenolic compounds in the xylan rich fraction (XRF) by polymerization within 1h. The insoluble products precipitated onto the carrier surface and could be reversible resolubilized by an aqueous ethanol solution. Consequently, an in situ product removal could be realized. The reusability of the immobilized laccase could be additionally shown. The reaction kinetics could be described by a reversible Michaelis Menten equation giving the prerequisite for scaling up the process. In a second step, the organic acids, hydroxymethylfurfural and phenolic acids could be further removed by employing an anion exchanger. Both, the laccase and the laccase+anion exchanger treatment enhanced successfully the fermentability of an organosolv wheat straw fraction.

Development and optimization of single and combined detoxification processes to improve the fermentability of lignocellulose hydrolyzates.

Controlled basic hydrolysis of poly(methyl methacrylate-co-ethylene glycol dimethacrylate) P(MMA-co-EGDMA) microparticles with a diameter d50=6 μm led to high densities of carboxylic groups at the particles' surface of up to 1.288 μeq g(-1) (equivalent to 1.277 μmol m(-2)). The microparticles' core has not been altered by this surface activation procedure as seen by fluorescent staining. The kinetics of the hydrolysis reaction was investigated via electrophoretic light scattering and particle charge detection employing polycation titration under shear condition. The activated microparticle's surface was subsequently exploited in carbodiimide-mediated coupling reactions using a variety of molecular reactants, that is, 11-azido-3,6,9-trioxaundecan-1-amine, cysteamine, propargylamine, and fluoresceinamine, thus enabling the introduction of chemically reactive moieties such as azides, thiols, and alkynes. Fluorescent staining of the particles' surface successfully demonstrated the versatile applications of surface functionalized microparticles via copper-catalyzed huisgen cycloaddition. Carrying on this two-step procedure in a controlled manner provides an excellent way for relatively simple but highly effective surface functionalization.

Surface etching of methacrylic microparticles via basic hydrolysis and introduction of functional groups for click chemistry.

Microalgae are discussed as a potential renewable feedstock for biofuel production. The production of highly concentrated algae biomass with a high fatty acid content, accompanied by high productivity with the use of natural sunlight is therefore of great interest. In the current study an outdoor pilot plant with five 30 L Flat Panel Airlift reactors (FPA) installed southwards were operated in 2011 in Stuttgart, Germany. The patented FPA reactor works on the basis of an airlift loop reactor and offers efficient intermixing for homogeneous light distribution. A lipid production process with the microalgae Chlorella vulgaris (SAG 211-12), under nitrogen and phosphorous deprivation, was established and evaluated in regard to the fatty acid content, fatty acid productivity and light yield. In the first set of experiments limitations caused by restricted CO₂ availability were excluded by enriching the media with NaOH. The higher alkalinity allows a higher CO₂ content of supplied air and leads to doubling of fatty acid productivity. The second set of experiments focused on how the ratio of light intensity to biomass concentration in the reactor impacts fatty acid content, productivity and light yield. The specific light availability was specified as mol photons on the reactor surface per gram biomass in the reactor. This is the first publication based on experimental data showing the quantitative correlation between specific light availability, fatty acid content and biomass light yield for a lipid production process under nutrient deprivation and outdoor conditions. High specific light availability leads to high fatty acid contents. Lower specific light availability increases fatty acid productivity and biomass light yield. An average fatty acid productivity of 0.39 g L⁻¹  day⁻¹ for a 12 days batch process with a final fatty acid content of 44.6% [w/w] was achieved. Light yield of 0.4 g mol photons⁻¹ was obtained for the first 6 days of cultivation.

Optimization of outdoor cultivation in flat panel airlift reactors for lipid production by Chlorella vulgaris.

The rice pathogen Fusarium fujikuroi is known for producing a wide range of secondary metabolites such as pigments, mycotoxins, and a group of phytohormones, the gibberellic acids (GAs). Bioactive forms of these diterpenes are responsible for hyperelongation of rice stems, yellowish chlorotic leaves, and reduced grain formation during the bakanae disease leading to severely decreased crop yields. GAs are also successfully applied in agriculture and horticulture as plant growth regulators to enhance crop yields, fruit size, and to induce earlier flowering. In this study, six F. fujikuroi wild-type and mutant strains differing in GA yields and the spectrum of produced GAs were cultivated in high-quality lab fermenters for optimal temperature and pH control and compared regarding their growth, GA production, and GA gene expression levels. Comparative analysis of the six strains revealed that strain 6314/ΔDES/ΔPPT1, holding mutations in two GA biosynthetic genes and an additional deletion of the 4'-phosphopantetheinyl transferase gene PPT1, exhibits the highest total GA amount. Expression studies of two GA biosynthesis genes, CPS/KS and DES, showed a constantly high expression level for both genes under production conditions (nitrogen limitation) in all strains. By cultivating these genetically engineered mutant strains, we were able to produce not only mixtures of different bioactive GAs (GA3, GA4, and GA7) but also pure GA4 or GA7. In addition, we show that the GA yields are not only determined by different production rates, but also by different decomposition rates of the end products GA3, GA4, and GA7 explaining the varying GA levels of genetically almost identical mutant strains.

Characterization of novel mutants with an altered gibberellin spectrum in comparison to different wild-type strains of Fusarium fujikuroi.

In this study, we present a powerful stirred tank reactor system that can efficiently hydrolyse lignocellulosic material at high solid content to produce hydrolysates with glucose concentration > 100 g/kg. As lignocellulosic substrates alkaline-pretreated wheat straw and organosolv-pretreated beech wood were used. The developed vertical reactor was equipped with a segmented helical stirrer, which was specially designed for high biomass hydrolysis. The stirrer was characterised according to mixing behaviour and power input. To minimise the cellulase dosage, a response surface plan was used. With the empirical relationship between glucose yield, cellulase loading and solid content, the minimal cellulase dosage was calculated to reach at least 70% yield at high glucose and high substrate concentrations within 48 h. The optimisation resulted in a minimal enzyme dosage of 30 FPU/g dry matter (DM) for the hydrolysis of wheat straw and 20 FPU/g DM for the hydrolysis of beech wood. By transferring the hydrolysis reaction from shaking flasks to the stirred tank reactor, the glucose yields could be increased. Using the developed stirred tank reactor system, alkaline-pretreated wheat straw could be converted to 110 g/kg glucose (76%) at a solid content of 20% (w/w) after 48 h. Organosolv-pretreated beech wood could be efficiently hydrolysed even at 30% (w/w) DM, giving 150 g/kg glucose (72%).

High solids enzymatic hydrolysis of pretreated lignocellulosic materials with a powerful stirrer concept.

A new concept is proposed for combined fermentation (two-stage high-load fermenter) and gasification (two-stage fluidised bed gasifier with CO2 separation) of sewage sludge and wood, and the subsequent utilisation of the biogenic gases in a hybrid power plant, consisting of a solid oxide fuel cell and a gas turbine. The development and optimisation of the important processes of the new concept (fermentation, gasification, utilisation) are reported in detail. For the gas production, process parameters were experimentally and numerically investigated to achieve high conversion rates of biomass. For the product gas utilisation, important combustion properties (laminar flame speed, ignition delay time) were analysed numerically to evaluate machinery operation (reliability, emissions). Furthermore, the coupling of the processes was numerically analysed and optimised by means of integration of heat and mass flows. The high, simulated electrical efficiency of 42% including the conversion of raw biomass is promising for future power generation by biomass.

Power generation based on biomass by combined fermentation and gasification--a new concept derived from experiments and modelling.

The basidiomycetous fungus Pseudozyma aphidis is able to convert vegetable oils to abundant amounts of the biosurfactant mannosylerythritol lipid (MEL) with a unique product pattern of MEL-A, MEL-B, MEL-C, and MEL-D. To investigate the metabolism of MEL production, we analyzed the transcriptome of P. aphidis DSM 70725 under MEL-inducing and non-inducing conditions using deep sequencing. Following manual curation of the previously described in silico gene models based on RNA-Seq data, we were able to generate an experimentally verified gene annotation containing 6347 genes. Using this database, our expression analysis revealed that only four of the five cluster genes required for MEL synthesis were clearly induced by the presence of soybean oil. The acetyltransferase encoding gene PaGMAT1 was expressed on a much lower level, which may explain the secretion of MEL with different degrees of acetylation in P. aphidis. In parallel to MEL synthesis, microscopic observations showed morphological changes accompanied by expression of genes responsible for cell development, indicative of a coregulation between MEL synthesis and cell morphology. In addition a set of transcription factors was identified which may be responsible for regulation of MEL synthesis and cell development. The upregulation of genes required for nitrogen metabolism and other assimilation processes indicate additional metabolic pathways required under the MEL-inducing conditions used. We also searched for a conserved gene cluster for cellobiose lipids (CL) but only found seven genes with limited homology distributed over the genome. However, we detected characteristic TLC spots in fermentations using P. aphidis DSM 70725, indicative of CL secretion.

Article	Year
The utilization of renewable resources in German industrial production. Biotechnology journal\| PubMed ID: 16897820	2006
Co-cultured production of lignin-modifying enzymes with white-rot fungi. Applied biochemistry and biotechnology\| PubMed ID: 21647688	2011
Raman spectroscopy: a noninvasive analysis tool for the discrimination of human skin cells. Tissue engineering. Part C, Methods\| PubMed ID: 21774693	2011
Amantichitinum ursilacus gen. nov., sp. nov., a chitin-degrading bacterium isolated from soil. International journal of systematic and evolutionary microbiology\| PubMed ID: 22345133	2013
Stiff gelatin hydrogels can be photo-chemically synthesized from low viscous gelatin solutions using molecularly functionalized gelatin with a high degree of methacrylation. Journal of materials science. Materials in medicine\| PubMed ID: 22890515	2012
Ammonia plasma treatment of polystyrene surfaces enhances proliferation of primary human mesenchymal stem cells and human endothelial cells. Biotechnology journal\| PubMed ID: 23070995	2013
Development and optimization of single and combined detoxification processes to improve the fermentability of lignocellulose hydrolyzates. Bioresource technology\| PubMed ID: 23454802	2013
Surface etching of methacrylic microparticles via basic hydrolysis and introduction of functional groups for click chemistry. Journal of colloid and interface science\| PubMed ID: 23481515	2013
Optimization of outdoor cultivation in flat panel airlift reactors for lipid production by Chlorella vulgaris. Biotechnology and bioengineering\| PubMed ID: 23616347	2013
Characterization of novel mutants with an altered gibberellin spectrum in comparison to different wild-type strains of Fusarium fujikuroi. Applied microbiology and biotechnology\| PubMed ID: 23636694	2013
High solids enzymatic hydrolysis of pretreated lignocellulosic materials with a powerful stirrer concept. Applied biochemistry and biotechnology\| PubMed ID: 24242162	2014
Power generation based on biomass by combined fermentation and gasification--a new concept derived from experiments and modelling. Bioresource technology\| PubMed ID: 25086436	2014
The transcriptomic profile of Pseudozyma aphidis during production of mannosylerythritol lipids. Applied microbiology and biotechnology\| PubMed ID: 25586580	2015

Thomas Hirth

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