Bioreactor Research Papers - Academia.edu (original) (raw)

The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native... more

The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase

There has been a rapid increase in the number and demand for approved biopharmaceuticals produced from animal cell culture processes over the last few years. In part, this has been due to the efficacy of several hu-manized monoclonal... more

There has been a rapid increase in the number and demand for approved biopharmaceuticals produced from animal cell culture processes over the last few years. In part, this has been due to the efficacy of several hu-manized monoclonal antibodies that are required at large ...

The concept of membrane bioreactor systems consists of – “Utilizing a bioreactor and microfiltration or ultra-filtration as one unit process for waste water treatment thereby replacing, and in some cases supplementing, the solids... more

The concept of membrane bioreactor systems consists of – “Utilizing a bioreactor and microfiltration or ultra-filtration as one unit process for waste water treatment thereby replacing, and in some cases supplementing, the solids separation function of secondary clarification and effluent filtration.” Early MBRs were based on pressurized modules in recirculation loops, but the current state of the art involves immersing the membranes in the activated sludge and drawing the treated water by suction. The idea of coupling activated sludge with membrane separation was conceived in the mid-1960s at Dorr-Oliver (Stanford, Connecticut), but the technology was not commercialized in North America. Thetford Systems (Ann Arbor, Michigan), which later became part of ZENON, accomplished this in the early 1970s. The company developed a membrane bioreactor system for on-site treatment and recycling of wastewater. The system, called Cycle Let was based on an aerobic – anoxic activated sludge process with tubular ultra-filtration (UF) in a two-pump feed and bleed loop. Permeate from the UF membranes was disinfected in a UV unit, and reused for toilet flushing.

This paper describes the performance of a novel bio-reactor system, the membrane-integrated fermentation reactor (MFR), for efficient continuous fermentation. The MFR, equipped with an autoclavable polyvinylidene difluoride membrane, has... more

This paper describes the performance of a novel bio-reactor system, the membrane-integrated fermentation reactor (MFR), for efficient continuous fermentation. The MFR, equipped with an autoclavable polyvinylidene difluoride membrane, has normally been used for biological wastewater treatment. The productivity of the MFR system, applied to the continuous production of pyruvic acid by the yeast Torulopsis glabrata, was remarkably high. The volumetric

Catabolic products from anaerobic fermentation processes are potentially of industrial interest. The volatile fatty acids and alcohols produced can be used as building blocks in chemical processes or applied directly as substrates in a... more

Catabolic products from anaerobic fermentation processes are potentially of industrial interest. The volatile fatty acids and alcohols produced can be used as building blocks in chemical processes or applied directly as substrates in a mixed culture process to produce bioplastics. Development of such applications requires a predictable and controllable product spectrum of the fermentation process. The aim of the research described in this paper was (i) to investigate the product spectrum of an open mixed culture fermentation (MCF) process as a function of the pH, using glucose as substrate, and (ii) to relate the product spectrum obtained to generalized biochemical and thermodynamic considerations. A chemostat was operated under carbon and energy limitation in order to investigate the pH effect on the product spectrum in a MCF process. A transition from CO2/H2 production at lower pH values to formate production at higher pH values was observed. The ratio of CO2/H2 versus formate production was found to be related to the thermodynamics of formate dehydrogenation to CO2/H2. This transition was associated with a shift in the catabolic products, from butyrate and acetate to ethanol and acetate, likely due to a decrease in the oxidation state of the electron carriers in the cell. The product spectrum of the MCF process as a function of the pH could largely be explained using general biochemical considerations. Biotechnol. Bioeng. 2007; 98: 69–79. © 2007 Wiley Periodicals, Inc.

In this study, we have investigated the bioleaching potential of a native strain of Acidithiobacillus ferrooxidans isolated from zinc and lead sulfide mines under varied ambient conditions of growth and substrate consumption. The effects... more

In this study, we have investigated the bioleaching potential of a native strain of Acidithiobacillus ferrooxidans isolated from zinc and lead sulfide mines under varied ambient conditions of growth and substrate consumption. The effects of intermittent irrigation, type of agglomeration, feed formulation in terms of acid, enriched salt solution, initial number of microorganism, and their interactions on the bioleaching of low-grade zinc sulfide ores (containing 5.78% zinc) on growth and biooxidation efficiency of the bacteria have been evaluated. Bioleaching capacities of the isolate were optimized by the utilization the Taguchi method (e-qualitic-4) for design of experiments. As a result, eight column bioreactors with 5.7 kg ore (100% <12 mm) capacity were fabricated. Through the analysis, continuous inoculation of the ores with the solution of A. ferrooxidans type and spraying a bacterial-rich solution into the agglomerator were found to be the most significant factors, whereas intermittent irrigation and interactions of parameters have less effect within the ranges investigated. The extraction of zinc was obtained under the optimal conditions more than 70% in 80 days, which is noticeable to compare with conventional bioleaching.

A generic “system on a plate” modular multicompartmental bioreactor array which enables microwell protocols to be transferred directly to the bioreactor modules, without redesign of cell culture experiments or protocols is described. The... more

A generic “system on a plate” modular multicompartmental bioreactor array which enables microwell protocols to be transferred directly to the bioreactor modules, without redesign of cell culture experiments or protocols is described. The modular bioreactors are simple to assemble and use and can be easily compared with standard controls since cell numbers and medium volumes are quite similar. Starting from fluid dynamic and mass transport considerations, a modular bioreactor chamber was first modeled and then fabricated using “milli-molding,” a technique adapted from soft lithography. After confirming that the shear stress was extremely low in the system in the range of useful flow rates, the bioreactor chambers were tested using hepatocytes. The results show that the bioreactor chambers can increase or maintain cell viability and function when the flow rates are below 500 µL/min, corresponding to wall shear stresses of 10−5 Pa or less at the cell culture surface. Biotechnol. Bioeng. 2010; 106: 127–137. © 2010 Wiley Periodicals, Inc.

Cavendish banana (Musa acuminata) is one of the most important fruits in the world. Cavendish shoots tissue culture using bubble column bioreactor can be a solution to produce high yielding plantlet and gallic acid due to the aeration... more

Cavendish banana (Musa acuminata) is one of the most important fruits in the world. Cavendish shoots tissue culture using bubble column bioreactor can be a solution to produce high yielding plantlet and gallic acid due to the aeration with minimum shear stress. In this study, the average growth rate, presence of gallic acid, and antioxidant activity (IC50) in the bubble column bioreactor (200 mL capacity) with the aeration rates of 1 mL/s and 2 mL/s using Murashige & Skoog half-strength liquid medium supplemented with 0.5 ppm gibberellic acid will be analyzed. The aeration system used was atmospheric air. The leaves and stems were extracted by maceration using 96% ethanol solvent (1:10 (w/v)). A qualitative phenolic test with FeCl3, thin layer chromatography, and antioxidant test with 2,2-diphenyl-1-picrylhydrazyl was carried out. The average growth rate in the bioreactor were 0.22 ± 0.001 g/day (1 mL/s) and 0.21 ± 0.001 g/day (2 mL/s). All the leaf and stem extracts showed positive...

For the cultivation of microorganisms, baffled shake flasks are employed when increased levels of oxygenation and mixing are required. Their use has been discouraged, however, due to the danger of a wetted sterile plug and the lower... more

For the cultivation of microorganisms, baffled shake flasks are employed when increased levels of oxygenation and mixing are required. Their use has been discouraged, however, due to the danger of a wetted sterile plug and the lower reproducibility of the experimental results. Consequently, there are only few studies dealing with this type of shaken bioreactor, and there is practically no characterization of this reactor type from a chemical engineering viewpoint. Therefore, a systematic study to elaborate the basic characteristics of the volumetric power consumption and the unfavorable out-of-phase phenomenon in baffled shake flasks is undertaken. A new type of measuring device was developed to measure the volumetric power consumption in a single shake flask. The volumetric power consumption was found to increase with increasing shaking frequency and with decreasing filling volume. Further, an independency of power consumption on the shaking diameter was observed as long as the fluid motion is in-phase. A comparison of two different baffle geometries demonstrated that deeper baffles cause more resistance to fluid flow. For the commonly employed shaking diameter of 25 mm, the investigated baffled flask types may not be operated in the in-phase state. A larger shaking diameter must therefore be employed. It was found for the first time that for all in-phase conditions, the dimensionless Newton number Ne′Ne′ is independent of the Reynolds number Re. Power consumption in baffled shake flasks may therefore be described by a characteristic Ne′Ne′ only dependent on the filling volume VLVL and the flask type. Even though there are quantitative differences, a qualitative similarity between fluid flow in stirred tanks and shake flasks has been demonstrated.

Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was... more

Polypropylene (PP) membranes and polyethylene (PE) surfaces were modified to enhance formation and shear resistance of nitrifying biofilms for wastewater treatment applications. A combination of plasma polymerization and wet chemistry was employed to ultimately introduce poly(ethyleneglycol) (PEG) chains with two different functional groups (-PEG-NH(2) and -PEG-CH(3)). Biofilm growth experiments using a mixed nitrifying bacterial culture revealed that the specific combination of PEG chains with amino groups resulted in most biofilm formation on both PP and PE samples. Detachment experiments showed similar trends: biofilms on -PEG-NH(2) modified surfaces were much stronger compared to the other modifications and the unmodified reference surfaces. Electrostatic interactions between the protonated amino group and negatively charged bacteria as well as PEG chain density which can affect the surface structure might be possible explanations of the superiority of the -PEG-NH(2) modificatio...

In order to determine biogas potential of defatted silk worm pupae waste, anaerobic batch digestion was carried out in a 1-l bioreactor and, based on the results, further experiments were conducted in a 20-l KVIC (Khadi and Village... more

In order to determine biogas potential of defatted silk worm pupae waste, anaerobic batch digestion was carried out in a 1-l bioreactor and, based on the results, further experiments were conducted in a 20-l KVIC (Khadi and Village Industries Commission) type digester under semi-...

Vero cells growth and rabies production in IPT-AF medium, a property animal-component-free medium are described in this work. Kinetics of cell growth and rabies virus (strain LP 2061) production were first conducted in spinner flasks.... more

Vero cells growth and rabies production in IPT-AF medium, a property animal-component-free medium are described in this work. Kinetics of cell growth and rabies virus (strain LP 2061) production were first conducted in spinner flasks. Over eight independent experiments, Vero cell growth in IPT-AF medium, on 2 g/l Cytodex 1 was consistent. An average Cd (cell division number) of 3.3+/-0.4 and a specific growth rate micro of 0.017+/-0.006 h(-1) were achieved. Such performances were comparable to those obtained in serum-containing medium (MEM+10% FCS). Rabies virus production on Vero cells in IPT-AF medium was also optimised in spinner flasks. The effects of multiplicity of infection (MOI), regulation of glucose level at 1 g/l and cell washing step, were investigated. The highest virus titer was achieved when the cells were infected at an MOI of 0.1; this level was equal to 10(7) FFU/ml. The step of medium exchange before cell infection can be omitted; nevertheless in this case glucose...

Large-scale transient transfection of mammalian cells is a recent and powerful technology for the fast production of milligram amounts of recombinant proteins (r-proteins). As many r-proteins used for therapeutic and structural studies... more

Large-scale transient transfection of mammalian cells is a recent and powerful technology for the fast production of milligram amounts of recombinant proteins (r-proteins). As many r-proteins used for therapeutic and structural studies are naturally secreted or engineered to be secreted, a cost-effective serum-free culture medium that allows their efficient expression and purification is required. In an attempt to design such a serum-free medium, the effect of nine protein hydrolysates on cell proliferation, transfection efficiency, and volumetric productivity was evaluated using green fluorescent protein (GFP) and human placental secreted alkaline phosphate (SEAP) as reporter genes. The suspension growing, serum-free adapted HEK293SF-3F6 cell line was stably transfected with an EBNA1-expression vector to increase protein expression when using EBV oriP bearing plasmids. Compared to our standard serum-free medium, concomitant addition of the gelatin peptone N3 and removal of BSA slightly enhanced transfection efficiency and significantly increased volumetric productivity fourfold. Using the optimized medium formulation, transfection efficiencies between 40–60% were routinely obtained and SEAP production reached 18 mg/L−1. To date, we have successfully produced and purified over fifteen r-proteins from 1–14-L bioreactors using this serum-free system. As examples, we describe the scale-up of two secreted his-tagged r-proteins Tie-2 and Neuropilin-1 extracellular domains (ED) in bioreactors. Each protein was successfully purified to >95% purity following a single immobilized metal affinity chromatography (IMAC) step. In contrast, purification of Tie-2 and Neuropilin-1 produced in serum-containing medium was much less efficient. Thus, the use of our new serum-free EBNA1 cell line with peptone-enriched serum-free medium significantly improves protein expression compared to peptone-less medium, and significantly increases their purification efficiency compared to serum-containing medium. This eliminates labor-intensive and expensive chromatographic steps, and allows for the simple, reliable, and extremely fast production of milligram amounts of r-proteins within 5 days posttransfection. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 84: 332–342, 2003.

Waste and wastewater treatment processes produce odours, which can cause a nuisance to adjacent populations and contribute significantly to atmospheric pollution. Sulphurous compounds are responsible for acid rain and mist; many organic... more

Waste and wastewater treatment processes produce odours, which can cause a nuisance to adjacent populations and contribute significantly to atmospheric pollution. Sulphurous compounds are responsible for acid rain and mist; many organic compounds of industrial origin contribute to airborne public health concerns, as well as environmental problems. Waste gases from industry have traditionally been treated using physicochemical processes, such as scrubbing, adsorption, condensation, and oxidation, however, biological treatment of waste gases has gained support as an effective and economical option in the past few decades. One emergent technique for biological waste gas treatment is the use of existing activated sludge plants as bioscrubbers, thus treating the foul air generated by other process units of the wastewater treatment system on site, with no requirement for additional units or for interruption of wastewater treatment. Limited data are available regarding the performance of activated sludge diffusion of odorous air in spite of numerous positive reports from full-scale applications in North America. This review argues that the information available is insufficient for precise process design and optimization, and simultaneous activated sludge treatment of wastewater and airborne odours could be adopted worldwide.