Media development

Factors that must be considered in developing a medium for large scale fermentations are  

The nutrient properties in relation to storage and handling, pasteurization or sterilization, processing and product purification 

In the calculation of the cost of the medium, all costs have to be recognized. Thus, in addition to the purchase price, which is obvious, 

Product concentration, yield, and productivity are among the most important process variables in determining conversion costs.The concentration of the product influences its recovery and refining costs. Raw material costs are affected by the yield. Productivity, or the rate of product formation per unit of process capacity, helps determine the amount of capital, labor, and indirect costs assignable to the product. The influence of the medium on the interplay of these three variables cannot be ignored. 

Raw material costs in fermentations may vary from 15 to 60% of the total manufacturing cost. Simply trying to cut manufacturing costs by substituting raw materials with cheaper ones may not be the answer. If carbohydrate costs represent, for example, 10% of the total manufacturing cost, it requires a 5 0% reduction in the carbon source to effect a 5% reduction in manufacturing cost. The question is then how the new raw material effects the multiple interactions of a complex medium. 

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Other imaging techniques such as magnetic resonance and ultrasound have opened up avenues of tremendous potential for contrast medium enhancement (123). Ultrasound contrast media developments have centered around encapsulated air micro-bubbles. Magnetic resonance contrast agents iavolve metal—ligand complexes and have evolved from ionic to nonionic species, much as radiopaques have. 

Fig. 20. Homogeneous rliodium-cataly2ed oxo process in biphasic media developed by Ruhrchemie/Rhc ne-Poulenc (83).

Semm is expensive, the 1992 price was 400/L, and supply depends on cattie supply. Use of this semm also poses significant difficulties in vahdating processes for absence of viral contamination. Hence, a goal in cell culture technology is to develop semm-free media for cell culture. Much work has gone into developing semm-free media and a sizable portion of cell culture research is devoted to this project. A detailed discussion of semm-free media development is available (5). 

Bifilm A sewage treatment process utilizing two aerated biological filters filled with granular plastic media. Developed by Biwater, UK, and piloted in 1994. 

Felmy, A. R., Rai, D. Mason, M. J. 1991. The solubility of hydrous thorium(IV) oxide in chloride media development of an aqueous ion-interaction model. Radiochimica Acta, 55, 177-185. 

M MCDB mitosis media developed at the Department of Molecular, Cellular and Developmental Biology, University of Colorado... 

Egeler P, Rombke J, Meller M, Knacker T, Nagel R. 1999. Bioaccumulation test with tubi-ficid sludgeworms in artificial media—development of a standardisable method. Hydrobiologia 406 271-280. 

Chapter 3 described a new model for transport through porous media, developed recently by Kerkhof [5] and called the binary friction model (BFM). It is of interest to see how this model can be applied to the description of available experiments and to compare the results with those of the dusty gas model (DGM). Kerkhof [5] took the experimental data of Evans et al. [6,7] for the permeation of He and Ar through a low-permeability porous graphite septum. The experimental set-up, similar to the Wicke-Kallenbach diffusion cell, is sketched in Figure 9.7. Of interest are the steady... 

In spite of these hurdles, the last two decades have seen an immense leap in animal cell culture technology both at the laboratory scale as well as the industrial scale. A variety of bioreactors and instrumentation have been ingeniously been devised for the scale up and process control of animal cell cultures. Serum-free media development has considerably reduced the downstream processing costs in the recombinant protein production and purification process. The capability to induce some cell lines to lose anchorage dependence has also been an important breakthrough. 

In a follow-up study Feinfeld et al. (F9) used an upper limit of normal for urinary ligandin excretion of >5 pg/liter. They found that patients who received 34 g or more of iodine in radiocontrast media developed elevated urinary ligandin... 

Media Development Project Editors Sarah Faulkner,... 

Fujita T., Kobayashi A. and Borgesson L. 1996. Experimental investigation and mathematical simulation on coupled T-H-M processes of the engineered buffer materials, the TC3 problem. In Stephansson O, Jing L, Tsang C-F editors. Coupled thermo-hydro-mechanical processes of fractured media. Developments in Geotechnical Engineering, No.79, Amsterdam Elsevier, pp.369-392. 

Tijani, S.M. 1996. Short description of VIPLEF code. Coupled thermo-hydro-mechanical processes of fractured media. Developments in Geotechnical Engineering, 79 507 - 511. 

Nguyen, T.S. 1996. Description of the computer code FRACON. In Stephansson, O., Jing, L., and Tsang, C.-F. editors. Coupled Thermohydro-mechanical Processes of Fractured Media. Developments in Geotechnical Engineering, Elsevier, 79 pp. 539-544. 

Several excellent references on microbial cell requirements and media development exist [4,7,18,24,25]. 

The focus of a media development program may be on completely defined media [26-29] and/or complex media [4,7,30]. A synthetic mediiun provides a better opportimity to monitor and define the nutritional requirements of a culture. However, productivity and cost are often superior with a complex mediiun, leading to its frequent use for manufactming-scale production [30]. With a complex medium it is difficult to monitor nutrients, metabolites, and frequently cell density. Lot-to-lot variability of the composition of these imde-fined components also represents a real problem, both to the development scientist and the manufacturing plant manager. In addition, complex media may result in more difficult analytical and pmification processes. With distinct benefits to each, both complex and defined media development avenues may be appropriate options to explore. 

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