Bioreactor Directive

The fifth paper, "A Separative Bioreactor Direct Product Capture and pH Control," presented by Seth Snyder of the Argonne National Laboratory, reviewed development and performance of a novel bioreactor incorporating electrodeionization to simultaneously produce and separate products from both enzymatic and microbially mediated reactions. The sixth paper, " Optimization of Xylose Fermentation in Spent Sulfite Liquor by Saccharomyces cerevisiae 259ST," presented by Steven Helle of the University of British Columbia, provided an overview of an approach to fermentation optimization utilized to identify key process variables limiting use of the SSL for commercial ethanol production. 

There have been numerous communications on the subject of biodegradation test methods, including aerobic compost (30), anaerobic bioreactor (31), general methodology and future directions (32—34), and a fine review article (24). ASTM (22) and MITI (35) have also set forth standard testing protocols for plastics, as shown in Table 2, whereas OECD test methods (29) are more suited to water-soluble polymers. 

The culture can be used directly for the conversion of phenylpyruvic add to resting cells L-phenylalanine. Therefore, a batch process with resting cells can be carried out, with some glucose added for maintenance (fed-batch fermentation). Another approach is to harvest the cells from the fermentation broth and to use them in a separate bioreactor in higher concentrations than the ones obtained in the cell cultivation. An advantage of the last method can be that the concentration of compounds other than L-phenylalanine is lower, so that downstream processing may be cheaper. 

At time t=212 h the continuous feeding was initiated at 5 L/d corresponding to a dilution rate of 0.45 d . Soon after continuous feeding started, a sharp increase in the viability was observed as a result of physically removing dead cells that had accumulated in the bioreactor. The viable cell density also increased as a result of the initiation of direct feeding. At time t 550 h a steady state appeared to have been reached as judged by the stability of the viable cell density and viability for a period of at least 4 days. Linardos et al. (1992) used the steady state measurements to analyze the dialyzed chemostat. Our objective here is to use the techniques developed in Chapter 7 to determine the specific monoclonal antibody production rate in the period 212 to 570 h where an oscillatory behavior of the MAb titer is observed and examine whether it differs from the value computed during the start-up phase. 

Liao, B.Q., Kraemer, J.T., and Bagley, D.M., Anaerobic membrane bioreactors Applications and research directions, Critical Reviews in Environmental Science and Technology, 36 (6), 489-530, 2006. 

Atlantic Richfield Company has reported strains of Pseudomonas sp. CB1 (ATCC 39381) [108] and Acinetobacter species CB2 [109] (ATCC 53515) to be effective for the removal of sulfur from organic molecules found in petroleum, coal, etc. In fact, the aerobic and heterotrophic soil microorganisms Pseudomonas CB1 and Acinetobacter CB2 were reported to convert thiophene sulfur into sulfate, using a bench-scale continuous bioreactor. The direct contact with Illinois 6 coal reduced the organic sulfur content in about 40% to 50%. As already mentioned, most of this work was carried out on coal. Further work was not pursued probably due to decrease in coal usage or due to the economics of the processes. 

A slurry bioreactor where carbonaceous feedstock is directly contacted with the biocatalyst. 

Polymer materials are frequently used matrices for the indicator chemistry in optical sensors. This is necessary for several reasons first, the indicator has to be immobilized to an optical waveguide or an optical fibre which is then brought into contact with the analyte solution. If one would pour an aqueous solution of the indicator dye directly into the sample solution, e.g. into a bioreactor, then the whole sample solution would be contaminated. 

Nowadays, studies of direct electrochemistry of redox proteins at the electrodesolution interface have held more and more scientists interest. Those studies are a convenient and informative means for understanding the kinetics and thermodynamics of biological redox processes. And they may provide a model for the study of the mechanism of electron transfer between enzymes in biological systems, and establish a foundation for fabricating new kinds of biosensors or enzymatic bioreactors. 

Biocompatible nanosized polyamidoamine (PAMAM) dendrimer films provided a suitable microenvironment for heme proteins to transfer electron directly with underlying pyrolytic graphite electrodes. The Mb-PAMAM film can catalytically reduced oxygen, hydrogen peroxide, and nitrite, indicating that the potential applicability of the film can be used to fabricate a new type of biosensor or bioreactor based on the direct electron transfer of Mb [234],... 

In this review, we focus on the use of plant tissue culture to produce foreign proteins that have direct commercial or medical applications. The development of large-scale plant tissue culture systems for the production of biopharmaceutical proteins requires efficient, high-level expression of stable, biologically active products. To minimize the cost of protein recovery and purification, it is preferable that the expression system releases the product in a form that can be harvested from the culture medium. In addition, the relevant bioprocessing issues associated with bioreactor culture of plant cells and tissues must be addressed. 

In the quest to find other plants that are suitable as bioreactors, various monocoty-ledonous and dicotyledonous species have been tested. These include corn [16], rice and wheat [17], alfalfa [18], potato [19, 20], oilseed rape [21], pea [22], tomato [23] and soybean [24]. The major advantage of cereal crops is that recombinant proteins can be directed to accumulate in seeds, which are evolutionar specialized for storage and thus protect proteins from proteolytic degradation. Recombinant proteins are reported to remain stable in seeds for up to five months at room temperature [17] and for at least three years at refrigerator temperature without significant loss of activity [25]. In addition, the seed proteome is less complex than the leaf proteome, which makes purification quicker and more economical [26]. 

Direct Black 38 Mixed microbial culture isolated from an aerobic bioreactor treating textile wastewater The dye was transformed into benzidine and 4-aminobiphenyl followed by complete biodegradation of these toxic intermediates [134]... 

Decolorization of azo dye R016 by immobilized cultures of I. lacteus was compared in three different reactor systems [59]. Different size of PuF was used for immobilization in reactors. Biomass concentration was reported to be 11.6, 8.3, and 4.9 g dw/L in Small Trickle Bed Reactor (STBR), Large Trickle Bed Reactor, and Rotating Disk Bioreactor, respectively. Decolorization rate was found high in STBR, where 90% decolorization rates were achieved after 3 days. Dye decolorization was highly efficient, but no direct relationship between the extracellular enzyme activities (laccase and MnP) and dye decolorization capacity was found. 

Yates C, Shepard CR, Papworth G et al (2007) Novel three-dimensional organotypic liver bioreactor to directly visualize early events in metastatic progression. Adv Cancer Res 97 225-246... 

The hybrid is able to produce more alkaloids than the basic callus, which is an undifferentiated mass of cells. Alkaloid production in cell cultures can be more successful with the immobihzation of plant cells and enzymes and by using bioreactor systems . Alkaloid produced in cell cultures can be isolated directly from this culture or from young plants grown from this culture. More than 250 alkaloids are reported to be produced by cell-culture techniques. Only a limited number of species have been researched in this respect. The species studied are known to produce alkaloids with special use in applications. The most researched alkaloids produced by cell cultures are mentioned in Table 25. 

Both direct and indirect biophotolysis routes suffer from a number of challenges that currently prohibit them from becoming commercially viable processes [180] these include, but are not limited to, solar energy conversion efficiency and the difficulty of bioreactor design. In particular the low solar energy to hydrogen conversion efficiency is a matter of major concern in the field of biophotolysis. The efficiency is calculated as [180,172] ... 

In addition, the GMA/EDMA copolymer proved to serve as a basic unit for the fabrication of highly permeable bioreactors in capillary format. Trypsin immobilization after epoxide ring opening with diethylamine and attachment of glutaraldehyde is mentioned as the probably most prominent example [64], The immobilization of trypsin was also carried out using another class of reactive monolithic methacrylate polymer, which is based on 2-vinyl-4,4-dimethylazlactone, acrylamide, and ethylene dimethacrylate [65]. In contrast to GMA/EDMA, trypsin can directly be immobilized onto this kind of monolith, as the 2-vinyl-4,4-dimethylazlactone moieties smoothly react with weak nucleophils even at room temperature. 

Zabriski and colleagues 145, 46] first used culture fluorescence as an on-line estimate of viable biomass during the batch cultivation of Saccharomyces cere-visiae, a species of Streptomyces, and a species of Thermoactinomyces. They simply linearized the fluorescence to biomass data in order to find a direct function between NADH-dependent culture fluorescence and biomass concentration in the bioreactor. In the following years several other authors reported - on the basis of these results - on the estimation of biomass concentration from culture fluorescence data as shown in Table 1. 

For on-line measurement the BioView sensor is connected directly by a 1.5-m bifurcated liquid light conductor (Lumatec, Germany) to a quartz window in a 25-mm electrode standard port of vessel bioreactor (Fig. 2). Contamination and sterilization problems could be avoided, because there is no contact between sensor and fermentation broth. 

Naruse et al. proposed another bioreactor design [22,23], in which porcine hepatocyte spheroids are immobilized on non-woven polyester fabric. This device allows more direct contact between hepatocytes and perfused medium and improves, therefore, the mass transfer capacity. The non-woven fabric module expressed better metabohc and synthetic functions at 24 hours than a hollow fiber module containing spheroids in suspension culture. Longer term results are not yet available and the immunoexclusion properties of this fabric have not been addressed. 

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