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Technische Cellulose wurde als möglicher Rohstoff zur fermentativen Produktbildung untersucht. Hierfür wird Cellulose in der Lignocellulose-Bioraffinerie hergestellt und daraus Hydrolysat gewonnen. Die Prüfung der technischen Hydrolysate als Substrate erfolgte anhand eines breiten Spektrums an Bioprodukten, von Kraftstoffen wie Ethanolund Butanol, bis zu den Dicarbonsäuren Itacon- und Bernsteinsäure. Dabei werden Bakterien, Hefen und Pilze als Produktionsorganismen eingesetzt. Die einzelnen Herstellverfahren stellen unterschiedliche Anforderungen an die Substrathandhabung. Im Fall der Ethanol- und Butanol-Gewinnung kann eine simultane Saccharifizierung und Fermentierung (SSF) durchgeführt werden. Aufgrund der Produkttoxizität erfordert die Butanol-Herstellung dabei eine In-situ-Produktabtrennung durch Lösemittelimprägnierte Partikel. Die Herstellung der beiden Dicarbonsäuren unterscheidet sich in der Sensitivität der verwendeten Mikroorganismen gegenüber Inhibitoren, die in Spuren im Hydrolysat enthalten sind. Die Bernteinsäurebildung mit Actinobacillussuccinogenes kann mit unbehandeltem Hydrolysat erfolgen. Dagegen erfordert die Gewinnung von Itaconsäure mit A. terreus eine Detoxifizierung des Hydrolysats. Insgesamt konnte gezeigt werden, dass sämtliche Bioraffinerie-Hydrolysate als Substrate für unterschiedliche Fermentationen geeignet sind.
Bacillus pumilus reveals a remarkably high resistance to hydrogen peroxide provoked oxidative stress
(2014)
Bacillus pumilus is characterized by a higher oxidative stress resistance than other comparable industrially relevant Bacilli such as B. subtilis or B. licheniformis. In this study the response of B. pumilus to oxidative stress was investigated during a treatment with high concentrations of hydrogen peroxide at the proteome, transcriptome and metabolome level. Genes/proteins belonging to regulons, which are known to have important functions in the oxidative stress response of other organisms, were found to be upregulated, such as the Fur, Spx, SOS or CtsR regulon. Strikingly, parts of the fundamental PerR regulon responding to peroxide stress in B. subtilis are not encoded in the B. pumilus genome. Thus, B. pumilus misses the catalase KatA, the DNA-protection protein MrgA or the alkyl hydroperoxide reductase AhpCF. Data of this study suggests that the catalase KatX2 takes over the function of the missing KatA in the oxidative stress response of B. pumilus. The genome-wide expression analysis revealed an induction of bacillithiol (Cys-GlcN-malate, BSH) relevant genes. An analysis of the intracellular metabolites detected high intracellular levels of this protective metabolite, which indicates the importance of bacillithiol in the peroxide stress resistance of B. pumilus.
Developing a new production host from a blueprint: Bacillus pumilus as an industrial enzyme producer
(2014)
1. Drug metabolizing enzymes and transporters play important roles in the absorption, metabolism, tissue distribution and excretion of various compounds and their metabolites and thus can significantly affect their efficacy and safety. Furthermore, they can be involved in drug–drug interactions which can result in adverse responses, life-threatening toxicity or impaired efficacy. Significant species differences in the interaction of compounds with drug metabolizing enzymes and transporters have been described.
2. In order to overcome the limitation of animal models in accurately predicting human responses, a large variety of mouse models humanized for drug metabolizing enzymes and to a lesser extent drug transporters have been created.
3. This review summarizes the literature describing these mouse models and their key applications in studying the role of drug metabolizing enzymes and transporters in drug bioavailability, tissue distribution, clearance and drug–drug interactions as well as in human metabolite testing and risk assessment.
4. Though such humanized mouse models have certain limitations, there is great potential for their use in basic research and for testing and development of new medicines. These limitations and future potentials will be discussed.
Molecular Modeling Approach to the Prediction of Mechanical Properties of Silica-Reinforced Rubbers
(2014)
Recently, we have suggested a nanomechanical model for dissipative loss in filled elastomer networks in the context of the Payne effect. The mechanism is based on a total interfiller particle force exhibiting an intermittent loop, due to the combination of short-range repulsion and dispersion forces with a long-range elastic attraction. The sum of these forces leads, under external strain, to a spontaneous instability of “bonds” between the aggregates in a filler network and attendant energy dissipation. Here, we use molecular dynamics simulations to obtain chemically realistic forces between surface modified silica particles. The latter are combined with the above model to estimate the loss modulus and the low strain storage modulus in elastomers containing the aforementioned filler-compatibilizer systems. The model is compared to experimental dynamic moduli of silica filled rubbers. We find good agreement between the model predictions and the experiments as function of the compatibilizer's molecular structure and its bulk concentration.
The Gram-positive endospore-forming bacterium Bacillus licheniformis can be found widely in nature and it is exploited in industrial processes for the manufacturing of antibiotics, specialty chemicals, and enzymes. Both in its varied natural habitats and in industrial settings, B. licheniformis cells will be exposed to increases in the external osmolarity, conditions that trigger water efflux, impair turgor, cause the cessation of growth, and negatively affect the productivity of cell factories in biotechnological processes. We have taken here both systems-wide and targeted physiological approaches to unravel the core of the osmostress responses of B. licheniformis. Cells were suddenly subjected to an osmotic upshift of considerable magnitude (with 1 M NaCl), and their transcriptional profile was then recorded in a time-resolved fashion on a genome-wide scale. A bioinformatics cluster analysis was used to group the osmotically up-regulated genes into categories that are functionally associated with the synthesis and import of osmostress-relieving compounds (compatible solutes), the SigB-controlled general stress response, and genes whose functional annotation suggests that salt stress triggers secondary oxidative stress responses in B. licheniformis. The data set focusing on the transcriptional profile of B. licheniformis was enriched by proteomics aimed at identifying those proteins that were accumulated by the cells through increased biosynthesis in response to osmotic stress. Furthermore, these global approaches were augmented by a set of experiments that addressed the synthesis of the compatible solutes proline and glycine betaine and assessed the growth-enhancing effects of various osmoprotectants. Combined, our data provide a blueprint of the cellular adjustment processes of B. licheniformis to both sudden and sustained osmotic stress.
Members of the species Bacillus pumilus get more and more in focus of the biotechnological industry as potential new production strains. Based on exoproteome analysis, B. pumilus strain Jo2, possessing a high secretion capability, was chosen for an omics-based investigation. The proteome and metabolome of B. pumilus cells growing either in minimal or complex medium was analyzed. In total, 1542 proteins were identified in growing B. pumilus cells, among them 1182 cytosolic proteins, 297 membrane and lipoproteins and 63 secreted proteins. This accounts for about 43% of the 3616 proteins encoded in the B. pumilus Jo2 genome sequence. By using GC–MS, IP-LC/MS and H NMR methods numerous metabolites were analyzed and assigned to reconstructed metabolic pathways. In the genome sequence a functional secretion system including the components of the Sec- and Tat-secretion machinery was found. Analysis of the exoproteome revealed secretion of about 70 proteins with predicted secretion signals. In addition, selected production-relevant genome features such as restriction modification systems and NRPS clusters of B. pumilus Jo2 are discussed.
The development of a cost-effective hydrolysis for crude cellulose is an essential part of biorefinery developments. To establish such high solid hydrolysis, a new solid state reactor with static mixing is used. However, concentrations >10% (w/w) cause a rate and yield reduction of enzymatic hydrolysis. By optimizing the synergetic activity of cellulolytic enzymes at solid concentrations of 9%, 17% and 23% (w/w) of crude Organosolv cellulose, glucose concentrations of 57, 113 and 152 g L⁻¹ are reached. However, the glucose yield decreases from 0.81 to 0.72gg⁻¹ at 17% (w/w). Optimal conditions for hydrolysis scale-up under minimal enzyme addition are identified. As result, at 23% (w/w) crude cellulose the glucose yield increases from 0.29 to 0.49gg⁻¹. As proof of its applicability, biobutanol, succinic and itaconic acid are produced with the crude hydrolysate. The potential of the substrate is proven e.g. by a high butanol yield of 0.33gg⁻¹.
A major part of edible oil is subjected to bleaching procedures, primarily with minerals applied as adsorbers. Their recycling is currently done either by regaining the oil via organic solvent extraction or by using the spent bleaching earth (SBE) as additive for animal feed, etc. As a new method, the reutilization of the by-product SBE for the microbiologic formation of acetone, butanol, and ethanol (ABE) is presented as proof-of-concept. The SBE was taken from a palm oil cleaning process. The recycling concept is based on the application of lipolytic clostridia strains. Due to considerably long fermentation times, co-fermentation with Candida rugosa and enzymatic hydrolyses of the bound oil with a subsequent clostridia fermentation are shown as alternative routes. Anaerobic fermentations under comparison of different clostridia strains were performed with glycerol media, enzymatically hydrolyzed palm oil and SBE. Solutes, side product compositions and productivities were quantified via HPLC. A successful production of ABE solutes from SBE has been done with a yield of 0.15 g butanol per gram of bound glycerol. Thus, the biotechnological recycling of the waste stream is possible in principle. Inhibition of the substrate suspension has been observed. A chromatographic ion-exchange of substrates increased the biomass concentration.
Die vorliegende Erfindung betrifft eine Vorrichtung und ein Verfahren zur Bestimmung des Kontaktwinkels eines flüssigen oder mit Flüssigkeit gefüllten Körpers. Dieser besteht aus einem Träger (1) und einer damit verbundenen, in einem Winkelbereich von mehr als 0° bis maximal 90° neigbaren Ebene (8) mit einer darin ausgebildeten Abrollbahn (9) für den flüssigen oder mit Flüssigkeit gefüllten Körper. An der Ebene (8) sind mehrere Sensoren (11, 12) zur Erfassung der Rolldauer des Körpers entlang der Rollstrecke angeordnet. Erfindungsgemäß ist vorgesehen, dass die Einstellung des Neigungswinkels der Ebene (8) über ein Winkelmessgerät (10) erfolgt, wodurch ein Abrollwinkel erfassbar ist, bei dem der Körper in Bewegung gerät. Aus der Rolldauer, der Rollstrecke und dem Abrollwinkel wird der Kontaktwinkel des Körpers ermittelt.