The Experts below are selected from a list of 1920 Experts worldwide ranked by ideXlab platform
A. Sanromán - One of the best experts on this subject based on the ideXlab platform.
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Investigation of several Bioreactor Configurations for laccase production by Trametes versicolor operating in solid-state conditions
Biochemical Engineering Journal, 2003Co-Authors: S. Rodríguez Couto, Diego Moldes, A Liébanas, A. SanrománAbstract:Abstract In the present paper, the production of laccase by Trametes versicolor (CBS 100.29) in laboratory-scale Bioreactors, operating in semi-solid-state conditions, was studied. Three Bioreactor Configurations were investigated in order to determine the most suitable one for laccase production: immersion, expanded-bed and tray. In addition, the nature of support employed (inert or non-inert) on laccase production was also evaluated. According to the results attained in the previous work by our research group, nylon sponge and barley bran was employed as an inert and as a lignocellulosic support, respectively. Higher laccase activities were produced operating with barley bran than with nylon sponge as a support in all the Configurations tested. As regards Bioreactor design, the tray Configuration led to the highest laccase activities especially operating with barley bran as a support, where activities of about 10-fold higher than that found in the corresponding cultivation with nylon sponge were attained. Therefore, it could be asserted that the tray Bioreactor is a very appropriate Bioreactor Configuration to produce laccase by T. versicolor in solid-state conditions operating with lignocellulosic supports.
Joaquim M. S. Cabral - One of the best experts on this subject based on the ideXlab platform.
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Suspension Culture of Human Induced Pluripotent Stem Cells in Single-Use Vertical-Wheel™ Bioreactors Using Aggregate and Microcarrier Culture Systems.
Nature, 2020Co-Authors: Diogo E S Nogueira, Carlos A. V. Rodrigues, Yas Hashimura, Sunghoon Jung, Brian Lee, Joaquim M. S. CabralAbstract:Human induced pluripotent stem cells (hiPSCs) have the potential to be used in a variety of biomedical applications, including drug discovery and Regenerative Medicine. The success of these approaches is, however, limited by the difficulty of generating the large quantities of cells required in a reproducible and controlled system. Bioreactors, widely used for industrial manufacture of biological products, constitute a viable strategy for large-scale production of stem cell derivatives. In this chapter, we describe the expansion of hiPSCs using the Vertical-Wheel™ Bioreactor, a novel Bioreactor Configuration specifically designed for the culture of shear-sensitive cells. We provide protocols for the expansion of hiPSCs in suspension, both as floating aggregates and using microcarriers for cell adhesion. These methods may be important for the establishment of a scalable culture of hiPSCs, allowing the manufacturing of industrial- or clinical-scale cell numbers.
Nuri Azbar - One of the best experts on this subject based on the ideXlab platform.
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Energy Recovery From Conventional Biogas Digester Effluent with a Novel Bioreactor Configuration
Waste and Biomass Valorization, 2017Co-Authors: Gülizar Çalışkan, Nuri AzbarAbstract:Anaerobic biotechnology offers both economic and ecological benefits for sustainable renewable energy production and sustainable agriculture practice. In this study, a novel Bioreactor Configuration, which is a combination of a continuous flow stirred-tank reactor (CSTR) and an up flow sludge blanket reactor (UASB), was used in order to valorize the residual organic content in the effluent of a conventional CSTR reactor. Thereby, maximum utilization of total COD potential was aimed by further processing of the residual COD from conventional farm based CSTR type digester effluent. The effluent of the CSTR reactor (dry matter 10%, HRT: 30 days) was fed into UASB reactors under varying HRT and Organic Loading Rate (OLR) conditions. Up to 98% COD removal was achieved in 4 L UASB reactor corresponding to maximum biogas production of 0.7 m3 biogas/kg CODremoved in UASB reactor. To the best of our knowledge, this integrated system is used for the first time to maximize the COD conversion into bio-methane during biogas production from laying hen litters. Thereby, a novel approach was presented a promising solution for the maximum valorization of animal manure as an alternative to conventional farm based biogas digester systems.
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Continuous biohydrogen production in immobilized biofilm system versus suspended cell culture
International Journal of Hydrogen Energy, 2012Co-Authors: Tugba Keskin, Laura Giusti, Nuri AzbarAbstract:Abstract In this study, the performance of a new cell immobilization material, namely ceramic ball, was examined for continuous biohydrogen production in comparison to suspended cell culture system (CSTR). Production of biohydrogen in both systems was assessed under thermophilic conditions. Both systems were operated at varying hydraulic retention times (HRT) by shortening HRT values from 24 to 1.5 h at an influent sucrose concentration of 10 g/l. The immobilized Bioreactor Configuration outcompeted the CSTR Bioreactor in terms of both volumetric hydrogen production (2.7 l H 2 /l/day for immobilized system @ HRT = 3 h and 0.5 l H 2 /l/day for CSTR @ HRT = 24 h) and resistance to cell-washout (CSTR reactor lost significant amount of biomass at short HRT values). It was concluded that immobilized Bioreactor Configuration is much more robust than CSTR against high organic loading rates and 5 fold more volumetric hydrogen production was achieved in 8 fold smaller immobilized Bioreactor.
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comparative analysis of thermophilic immobilized biohydrogen production using packed materials of ceramic ring and pumice stone
International Journal of Hydrogen Energy, 2011Co-Authors: Tugba Keskin, Elif Aksoyek, Nuri AzbarAbstract:Abstract Ceramic ring and pumice stone were used as a support matrix for the enhancement of biohydrogen production in immobilized cell culture systems. The reactors were continuously operated for the hydrogen fermentation using sucrose as the major carbon source at varying hydraulic retention times (HRT) as an important operational factor. In terms of volumetric hydrogen production, the best value was obtained with ceramic ring at 1.5 h HRT (2.98 l H 2 /l/d), on the other hand, the pumice stone packed reactor resulted in 30% less volumetric hydrogen production (2.28 l H 2 /l/d) at two fold longer retention time (HRT 3 h). It was demonstrated that volumetric hydrogen production with the immobilized Bioreactor Configurations was 6 fold better than the suspended culture Bioreactor Configuration (CSTR). Furthermore, up to 4 mol and 5 mol hydrogen yields per mole of sucrose used (which are 62.5% and 50% of the theoretical values) were achieved by pumice stone and ceramic ring packed reactors, respectively, whereas suspended culture system yielded only 0.5 mol H 2 /mol sucrose.
Debabrata Das - One of the best experts on this subject based on the ideXlab platform.
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The prospect of purple non-sulfur (PNS) photosynthetic bacteria for hydrogen production: The present state of the art
World Journal of Microbiology and Biotechnology, 2007Co-Authors: Nitai Basak, Debabrata DasAbstract:Hydrogen is the fuel for the future, mainly due to its recyclability and nonpolluting nature. Biological hydrogen production processes are operated at ambient temperature and atmospheric pressures, thus are less energy intensive and more environmentally friendly as compared to thermochemical and electrochemical processes. Biohydrogen processes can be broadly classified as: photofermentation and dark fermentation. Two enzymes namely, nitrogenase and hydrogenase play an important role in biohydrogen production. Photofermentation by Purple Non-Sulfur bacteria (PNS) is a major field of research through which the overall yield for biological hydrogen production can be improved significantly by optimization of growth conditions and immobilization of active cells. The purpose of this paper is to review various processes of biohydrogen production using PNS bacteria along with several current developments. However, suitable process parameters such as carbon and nitrogen ratio, illumination intensity, Bioreactor Configuration and inoculum age may lead to higher yields of hydrogen generation using PNS bacteria.
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Simulation and modeling of continuous H2 production process by Enterobacter cloacae IIT-BT 08 using different Bioreactor Configuration
Enzyme and Microbial Technology, 2002Co-Authors: Debabrata Das, P.k Badri, Narendra Kumar, Pinaki BhattacharyaAbstract:Abstract Simulation and modeling of continuous H 2 production by Enterobacter cloacae IIT-BT 08 using different Bioreactor Configurations have been carried out and a suitable kinetic model for the substrate degradation has been proposed, assuming ideal plug flow, no axial dispersion, steady state and first-order substrate degradation kinetics. The degradation kinetics was investigated as a function of flow rates considering the gas hold-up in all the Bioreactors. The external film diffusion model of the type J D = KN Re −(1− n ) is proposed for a tubular Bioreactor and J D is found to be constant in the present system. The same model is applied to both tapered and rhomboidal Bioreactors and was found to give reasonably good fit with experimental results with respect to substrate conversion. Comparison of the external mass transfer coefficient k l with the observed first-order reaction rate constant k p predicted by the model shows that the effect of external film diffusion on the observed substrate degradation rate decreases with increasing flow rates. For the present system, both substrate degradation and mass transfer steps are the limiting factor for the observed substrate degradation rate, particularly at higher dilution rates.
Dirk Weusterbotz - One of the best experts on this subject based on the ideXlab platform.
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reversible retrofitting of a stirred tank Bioreactor for gas lift operation to perform synthesis gas fermentation studies
Biochemical Engineering Journal, 2019Co-Authors: Peter Riegler, Thomas Chrusciel, A E Mayer, Kathrin Doll, Dirk WeusterbotzAbstract:Abstract A retrofit approach enables the non-invasive and reversible modification of a commercially available stirred-tank Bioreactor into a gas-lift Bioreactor within a few minutes. The gas-lift Bioreactor Configuration was characterised using a non-coalescent medium at working volume-specific volumetric gas flow rates of up to 20 L L−1 h−1, showing mean gas bubble diameters of up to 0.57 mm, volumetric power inputs of up to 23 W m-3, gas-liquid mass transfer coefficients of up to 153 h−1 (CO) and up to 122 h−1 (H2), mixing times (θ90) of down to 0.5 min and gas hold-ups of up to 1.2%. A comparison of autotrophic batch processes with Clostridium aceticum and Clostridium carboxidivorans in the stirred-tank (2.0 L) and the retrofitted gas-lift Bioreactor (2.5 L) at identical operating conditions showed differences in the cell dry weight and product concentrations (acetate, ethanol, butyrate, 1-butanol, hexanoate, 1-hexanol) due to gas-liquid mass transfer limitations caused by the reduced power input in the gas-lift Bioreactor. CO limitation was demonstrated by a myoglobin-protein assay for CO measurement in the liquid phase. The simple retrofitting of a stirred-tank Bioreactor for gas-lift operation thus provided comparative data on process performances of acetogenic bacteria that convert synthesis gas in gas-lift and stirred-tank Bioreactors on a lab-scale.