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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.
An immunochromatographic lateral flow dipstick assay for the fast detection of microcystin-LR was developed. Colloid gold particles with diameters of 40 nm were used as red-colored antibody labels for the visual detection of the antigen. The new dipstick sensor is capable of detecting down to 5 µg·l−1 (ppb; total inversion of the color signal) or 1 ppb (observation of color grading) of microcystin-LR. The course of the labeling reaction was observed via spectrometric wave shifts caused by the change of particle size during the binding of antibodies. Different stabilizing reagents showed that especially bovine serum albumin (BSA) and casein increase the assays sensitivity and the conjugate stability. Performance of the dipsticks was quantified by pattern processing of capture zone CCD images. Storage stability of dipsticks and conjugate suspensions over 115 days under different conditions were monitored. The ready-to-use dipsticks were successfully tested with microcystin-LR-spiked samples of outdoor drinking- and salt water and applied to the tissue of microcystin-fed mussels.
Paracoccus denitrificans for the effluent recycling during continuous denitrification of liquid food
(2010)
Nitrate is an undesirable component of several foods. A typical case of contamination with high nitrate contents is whey concentrate, containing nitrate in concentrations up to 25 l. The microbiological removal of nitrate by Paracoccus denitrificans under formation of harmless nitrogen in combination with a cell retention reactor is described here. Focus lies on the resource-conserving design of a microbal denitrification process. Two methods are compared. The application of polyvinyl alcohol-immobilized cells, which can be applied several times in whey feed, is compared with the implementation of a two step denitrification system. First, the whey concentrate's nitrate is removed by ion exchange and subsequently the eluent regenerated by microorganisms under their retention by crossflow filtration. Nitrite and nitrate concentrations were determined by reflectometric color measurement with a commercially available Reflectoquant® device. Correction factors for these media had to be determined. During the pilot development, bioreactors from 4 to 250 mg·L-1 and crossflow units with membrane areas from 0.02 to 0.80 m2 were examined. Based on the results of the pilot plants, a scaling for the exemplary process of denitrifying 1,000 tons per day is 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.
Due to the interfering effects of acetic acid in many fermentation processes, a gas-diffusion technique was developed for the online determination of acetic acid. The measurements were accomplished with a flow diffusion analysis (FDA) unit from the TRACE Analytics GmbH, Braunschweig, Germany. The diffusion analysis is based on the UV-absorbance of acetic acid at 205 nm. The measurement was achieved by the separation of an acceptor and a carrier stream (acidified fermentation broth) using a gas permeable polytetrafluoroethylene (PTFE) membrane, whereby broth constituents that would otherwise disturb the UV-measurement of acetic acid, are held back efficiently. Merely, the fermentation by-products, e.g. formic acid, is capable of diffusing through the membrane. While formic acid can disturb the measurement, carbon dioxide does not absorb at 205 nm. The method operates with time-dependent sample enrichment. During the analysis, a small volume of the acceptor stream is stopped for a defined time interval in the acceptor chamber. During this period, the gaseous acetic acid diffuses through the membrane and is enriched in the acceptor chamber. Subsequently after the enrichment, the acceptor stream flows through a UV-detector. The intensity of the signal is proportional to the acetic acid concentration. Online measurements in bioreactors via a sterile filtration probe have been accomplished. A linear calibration in the range of 0.5–5.0 g/L acetic acid with a relative standard deviation of <5 % was obtained. A sampling rate of 8 samples per hour was possible. The system was applied for the determination of acetic acid in E. coli fermentation broth. The instrument is easy to clean, very user-friendly and does not require any toxic or expensive reagents.
Biotechnological downstream processing is usually an elaborate procedure, requiring a multitude of unit operations to isolate the target component. Besides the disadvantageous space-time yield, the risks of cross-contaminations and product loss grow fast with the complexity of the isolation procedure. A significant reduction of unit operations can be achieved by application of magnetic particles, especially if these are functionalized with affinity ligands. As magnetic susceptible materials are highly uncommon in biotechnological processes, target binding and selective separation of such particles from fermentation or reactions broths can be done in a single step. Since the magnetizable particles can be produced from iron salts and low priced polymers, a single-use implementation of these systems is highly conceivable. In this article, the principles of magnetizable particles, their synthesis and functionalization are explained. Furthermore, applications in the area of reaction engineering, microfluidics and downstream processing are discussed focusing on established single-use technologies and development potential.
Even the shortest flight through unknown, cluttered environments requires reliable local path planning algorithms to avoid unforeseen obstacles. The algorithm must evaluate alternative flight paths and identify the best path if an obstacle blocks its way. Commonly, weighted sums are used here. This work shows that weighted Chebyshev distances and factorial achievement scalarising functions are suitable alternatives to weighted sums if combined with the 3DVFH* local path planning algorithm. Both methods considerably reduce the failure probability of simulated flights in various environments. The standard 3DVFH* uses a weighted sum and has a failure probability of 50% in the test environments. A factorial achievement scalarising function, which minimises the worst combination of two out of four objective functions, reaches a failure probability of 26%; A weighted Chebyshev distance, which optimises the worst objective, has a failure probability of 30%. These results show promise for further enhancements and to support broader applicability.
Digital Image Correlation (DIC) is a powerful tool used to evaluate displacements and deformations in a non-intrusive manner. By comparing two images, one of the undeformed reference state of a specimen and another of the deformed target state, the relative displacement between those two states is determined. DIC is well known and often used for post-processing analysis of in-plane displacements and deformation of specimen. Increasing the analysis speed to enable real-time DIC analysis will be beneficial and extend the field of use of this technique.
Here we tested several combinations of the most common DIC methods in combination with different parallelization approaches in MATLAB and evaluated their performance to determine whether real-time analysis is possible with these methods. To reflect improvements in computing technology different hardware settings were also analysed. We found that implementation problems can reduce the efficiency of a theoretically superior algorithm such that it becomes practically slower than a suboptimal algorithm. The Newton-Raphson algorithm in combination with a modified Particle Swarm algorithm in parallel image computation was found to be most effective. This is contrary to theory, suggesting that the inverse-compositional Gauss-Newton algorithm is superior. As expected, the Brute Force Search algorithm is the least effective method. We also found that the correct choice of parallelization tasks is crucial to achieve improvements in computing speed. A poorly chosen parallelisation approach with high parallel overhead leads to inferior performance. Finally, irrespective of the computing mode the correct choice of combinations of integerpixel and sub-pixel search algorithms is decisive for an efficient analysis. Using currently available hardware realtime analysis at high framerates remains an aspiration.
Organization and management of German-Russian joint ventures. Bock, Jürgen; Thielemann, Frank
(1994)
Commercial materials with polyvinylpolypyrrolidone and polymeric amberlites (XAD7HP, XAD16) are commonly used for the adsorptive downstream processing of polyphenols from renewable resources. In this study, beta-zeolite-based adsorbent systems were examined, and their properties were compared to organic resins. Batch adsorption experiments were conducted with synthetic solutions of major polyphenols. Adsorption isotherms and desorption characteristics of individual adsorbent were determined based on these results. Maximum adsorption capacities were calculated using the Langmuir model. For example, the zeolites had capacities up to 203.2 mg/g for ferulic acid. To extend these results to a complex system, additional experiments were performed on rapeseed meal and wheat seed extracts as representative renewable resources. HPLC analysis showed that with 7.5% w/v, which is regarded as the optimum amount of zeolites, zeolites A and B could bind 100% of the major polyphenols as well as release polyphenols at high yields. Additionally, regeneration experiments were performed with isopropyl alcohol at 99°C to evaluate how zeolites regenerate under mild conditions. The results showed only a negligible loss of adsorption capacity and no loss of desorption capacity. In summary, it was concluded that beta-zeolites were promising adsorbents for developing new processes to isolate polyphenols from renewable resources.
BACKGROUND
Currently, several techniques exist for the downstream processing of protein, phytic acid and sinapic acid from rapeseed and rapeseed meal, but no technique has been developed to separate all of the components in one process. In this work, two new downstream processing strategies focusing on recovering sinapic acid, phytic acid and protein from rapeseed meal were established.
RESULTS
The sinapic acid content was enhanced by a factor of 4.5 with one method and 5.1 with the other. The isolation of sinapic acid was accomplished using a zeolite-based adsorbent with high adsorptive and optimal desorption characteristics. Phytic acid was isolated using the anion-exchange resin Purolite A200®. In addition, the processes resulted in two separated protein fractions. The ratios of globulin and albumin ratio to the total protein were 59.2% and 40.1%, respectively. The steps were then combined in two different ways: (a) a ‘sequential process’ using the zeolite and A200 in batch processes; and (b) a ‘parallel process’ using only A200 in a chromatographic system to separate all of the compounds.
CONCLUSIONS
It can be concluded that isolation of all three components was possible in both processes. These could enhance the added value of current processes using rapeseed meal as a protein source. © 2015 Society of Chemical Industry
Cell spraying has become a feasible application method for cell therapy and tissue engineering approaches. Different devices have been used with varying success. Often, twin-fluid atomizers are used, which require a high gas velocity for optimal aerosolization characteristics. To decrease the amount and velocity of required air, a custom-made atomizer was designed based on the effervescent principle. Different designs were evaluated regarding spray characteristics and their influence on human adipose-derived mesenchymal stromal cells. The arithmetic mean diameters of the droplets were 15.4–33.5 µm with decreasing diameters for increasing gas-to-liquid ratios. The survival rate was >90% of the control for the lowest gas-to-liquid ratio. For higher ratios, cell survival decreased to approximately 50%. Further experiments were performed with the design, which had shown the highest survival rates. After seven days, no significant differences in metabolic activity were observed. The apoptosis rates were not influenced by aerosolization, while high gas-to-liquid ratios caused increased necrosis levels. Tri-lineage differentiation potential into adipocytes, chondrocytes, and osteoblasts was not negatively influenced by aerosolization. Thus, the effervescent aerosolization principle was proven suitable for cell applications requiring reduced amounts of supplied air. This is the first time an effervescent atomizer was used for cell processing.
Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers
(2014)
Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or “postural instability” even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B₀ (n = 20), 7 T in & out B₀ (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in & out B₀. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B₀) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B₀ or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in & out B₀ exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or “over-compensation” of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.