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Carrier Material (carrier + material)
Selected AbstractsBiofiltration of waste gases in a reactor with a split-feedJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2003JA Mendoza Abstract The efficiency of using different feed strategies was evaluated in the case of a gas-phase biofilter packed with an inert carrier material. During a preliminary control-period, the biofilter was first fed with a single downflow feed of toluene. Reactor performance and biomass distribution were evaluated. The feed was then split into two flows before entering the reactor. Different feed ratios were tested during a 6-month period, following the preliminary control stage. Splitting the feed into equal flow rates through the upper and middle part of the biofilter (in a 50 : 50 ratio) improved the performance compared with the single-feed period. Such a high performance could also be maintained when using a higher flow rate for the upper port than for the middle port, with a feed-ratio of approximately 70 : 30, when more biomass was formed in the upper half of the filter bed. However, performance decreased when inverting this ratio from 70 : 30 to 30 : 70, ie when the highest flow rate was fed through the middle port of the biofilter. Copyright © 2003 Society of Chemical Industry [source] Direct drug loading into preformed porous solid dosage units by the controlled particle deposition (CPD), a new concept for improved dissolution using SCF-technologyJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2008Ragna S. Wischumerski Abstract The controlled particle deposition (CPD), a supercritical fluid precipitation process, is used to load porous tablets with ibuprofen to improve drug dissolution. Porous tablets (porosity 44.3,±,5.5%), consisting of microcrystalline cellulose pellets and hydroxyethylcellulose, or sugar cubes (porosity 37.2,±,0.5%), are used as carrier material. Loading experiments are conducted at 313 K and 25 MPa, drug concentrations between 6.25 and 33.3 mg ibuprofen/mL supercritical carbon dioxide and contact times of 15.5 h or 5 min. The resulting products have drug contents of 3,5 g ibuprofen/mL void volume in the carrier. Comparison of a predicted value, calculated from pore volume and loading concentration to the actual drug concentrations yielded by the loading process demonstrates the efficiency and controllability of the process. The mean particle size d50 of deposited ibuprofen is around 25 µm, half the size of the starting material. Drug dissolution from loaded carriers is significantly increased by a rise in the dissolution coefficient from 0.07 min,1 for the starting material to 0.13 or 0.14 min,1 for the CPD products. The CPD method therefore is presented as a feasible and controllable process to load porous solid dosage forms with drug particles in order to improve dissolution. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4416,4424, 2008 [source] The secretome of Pleurotus sapidusPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2005Holger Zorn Dr. Abstract Due to their unique capability to attack lignified biopolymers, extracellular enzymes of white-rot fungi enjoy an increasing interest in various fields of white biotechnology. The edible fungus Pleurotus sapidus was selected as a model organism for the analysis of the secretome by means of 2-DE. For enzyme production, the fungus was grown in submerged cultures either on peanut shells or on glass wool as a carrier material. Identification of the secreted enzymes was performed by tryptic digestion, ESI-MS/MS ab initio sequencing, and homology searches against public databases. The spectrum of secreted enzymes comprised various types of hydrolases and lignolytic enzymes of the manganese peroxidase/versatile peroxidase family. While peptidases were secreted mainly by the cultures grown on peanut shells, versatile peroxidase type enzymes dominated in the cultures grown on glass wool. [source] Virulent spores of Bacillus anthracis and other Bacillus species deposited on solid surfaces have similar sensitivity to chemical decontaminantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007J-L. Sagripanti Abstract Aims:, To compare the relative sensitivity of Bacillus anthracis and spores of other Bacillus spp. deposited on different solid surfaces to inactivation by liquid chemical disinfecting agents. Methods and Results:, We prepared under similar conditions spores from five different virulent and three attenuated strains of B. anthracis, as well as spores of Bacillus subtilis, Bacillus atrophaeus (previously known as Bacillus globigii), Bacillus cereus, Bacillus thuringiensis and Bacillus megaterium. As spore-surface interactions may bias inactivation experiments, we evaluated the relative binding of different spores to carrier materials. The survival of spores deposited on glass, metallic or polymeric surfaces were quantitatively measured by ASTM standard method E-2414-05 which recovers spores from surfaces by increasing stringency. The number of spores inactivated by each decontaminant was similar and generally within 1 log among the 12 different Bacillus strains tested. This similarity among Bacillus strains and species was observed through a range of sporicidal efficacy on spores deposited on painted metal, polymeric rubber or glass. Conclusions:, The data obtained indicate that the sensitivity of common simulants (B. atrophaeus and B. subtilis), as well as spores of B. cereus, B. thuringiensis, and B. megaterium, to inactivation by products that contain either: peroxide, chlorine or oxidants is similar to that shown by spores from all eight B. anthracis strains studied. Significance and Impact of the Study:, The comparative results of the present study suggest that decontamination and sterilization data obtained with simulants can be safely extrapolated to virulent spores of B. anthracis. Thus, valid conclusions on sporicidal efficacy could be drawn from safer and less costly experiments employing non-pathogenic spore simulants. [source] Sediment dynamics and pollutant mobility in rivers: An interdisciplinary approachLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2004Ulrich Förstner Abstract Characteristic dynamic features of sediment-related processes in rivers include dramatic effects of stormwater events on particle transport, rapid and far-reaching effects of sulphide oxidation during resuspension, and biological accumulation and potential release of toxic chemicals. Pollutant mobility is the net result of the stabilizing and mobilizing effects in both hydraulic and chemical fields. In practice, emphasis has to be given to fine-grained sediments and suspended matter as these materials exhibit large surface areas and high sorption capacities. Organic materials are highly reactive. Degradation of organic matter will induce oxygen depletion and might enhance formation of flocs and biofilms. Study of variations of sediment and water chemistry should predominantly include changes of pH and redox conditions, competition of dissolved ions and processes such as complexation by organic substances. Major questions relate to the potential reduction of sorption sites on minerals and degradation of organic carrier materials. All these processes will influence solution/solid equilibrium conditions and have to be studied prior to modelling the overall effects of pollutants on the water body and aquatic ecosystems. With respect to handling and remediation of contaminated river sediments, either in-place or excavated, a chemical and biological characterization of the material, of the (disposal) site and of the long-term processes is crucial. Passive techniques (e.g. in situ stabilization, subaqueous capping) provide economic advantages as there are no operation costs following their installation. However, the success of these ecological and geochemical engineering approaches is mainly based on an in-depth knowledge of the underlying processes. [source] Continuous Beer Fermentation Using Immobilized Yeast Cell Bioreactor SystemsBIOTECHNOLOGY PROGRESS, Issue 3 2005Brányik Traditional beer fermentation and maturation processes use open fermentation and lager tanks. Although these vessels had previously been considered indispensable, during the past decades they were in many breweries replaced by large production units (cylindroconical tanks). These have proved to be successful, both providing operating advantages and ensuring the quality of the final beer. Another promising contemporary technology, namely, continuous beer fermentation using immobilized brewing yeast, by contrast, has found only a limited number of industrial applications. Continuous fermentation systems based on immobilized cell technology, albeit initially successful, were condemned to failure for several reasons. These include engineering problems (excess biomass and problems with CO2 removal, optimization of operating conditions, clogging and channeling of the reactor), unbalanced beer flavor (altered cell physiology, cell aging), and unrealized cost advantages (carrier price, complex and unstable operation). However, recent development in reactor design and understanding of immobilized cell physiology, together with application of novel carrier materials, could provide a new stimulus to both research and application of this promising technology. [source] | |||||||||||||