Optimization, Escherichia coli

In current practice the fluorescence assay is often followed by the use of hybridization techniques when more selectivity is required. We have for instance used the fluorescence techniques to obtain data on the nucleic acid content of malaria vaccine proteins produced in Escherichia coli. The rapid turnaround time of the fluorescence assay is particularly useful during the early stages of purification to determine the optimal process conditions. After the final process has been arrived at and a variety of methods used to assess the nucleic acid content (including the hybridization techniques), the fluorescence method can be developed for routine quality-control purposes. In certain cases, particularly at high protein concentrations, the dye may bind to the protein with... 

Ibarra RU, Edwards JS, Palsson BO. Escherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth. Nature 2002 420 186-9. 

Clugston SL, JFJ Barnard, R Kinach, D Miedema, R Ruman, E Daub, JF Honek (1998) Overproduction and characterization of a dimeric non-zinc glyoxalase I from Escherichia coli evidence for optimal activation by nickel ions. Biochemistry 37 8754-8763. 

McMahan, S.A., and Burgess, R.R. (1994) Use of aryl azide cross-linkers to investigate protein-protein interactions An optimization of important conditions as applied to Escherichia coli RNA polymerase and localization of a tr70-a cross-link to the C-terminal region of a. Biochemistry 33, 12092-12099. 

EGF (synthetic gene) CaMV 35S promoter/ nos terminator Codon-optimized for high level peptide expression in Escherichia coli N. tabacum (leaves) 0.001% ofTSP 38... 

D. Visser, J. W. Schmid, K.Mauch, M. Reuss, and J. J. Heijnen, Optimal re design of primary metabolism in Escherichia coli using linlog kinetics. Metab. Eng. 6(4), 378 390 (2004). 

Merli, S., A. Corti, and G. Cassani (1995). Production of soluble tumor necrosis factor receptor type I in Escherichia coli optimization of the refolding yields by a microtiter dilution assay. Anal Biochem 230(1) 85-91. 

It has been shown that radio frequency impedance (RFI) is an effective tool for moifitoring cell density and cell growth of bioprocesses. The fermentation process, quite complex, is oftentimes difficult to sample and monitor. The RFI measurement could detect cell viability of Escherichia coli during the fermentation, serving as a qualitative measure of the metabolic load of the cell, and thus provide an in situ indicator of the optimal harvesting times. 

Historically, HCDC was first established for yeasts to produce single-ceU protein, ethanol, and biomass. Later, dense cultures of other mesophiles producing various types of products were developed, e.g.,by Suzuki et al. [96]. The combination of recombinant DNA technology and large-scale culture processes has enabled human proteins to be produced in a number of hosts, in particular in Escherichia coli [97-100]. Approaches to optimize the production of recombinant proteins are the subject of recent reviews from Winter et al. [101]. 

High cell densities are not only a prerequisite for high productivity additionally an effective on-line control and modeling of the bioprocesses is necessary. For industrial applications, optical measurement methods are more attractive because they are non-invasive and more robust. The potential of the BioView sensor for on-line bioprocess monitoring and control was tested. For high-cell-density cultivation of Escherichia coli, maintaining aerobic conditions and removal of inhibitory by-products are essential. Acetic acid is known to be one of the critical metabolites. Information about changes in the cell metabolism and the time of important process operations is accessible on-line for optimization... 

Glycolipid incorporated liposomes have found extensive use as sensors for the detection of Escherichia coli bacteria. Liposomes prepared using a diacetylene and a glucosyl lipid underwent a chromatic transition upon the addition of E. coli (Ma et al. 1998). The chromatic transition is sensitive to the diyne and glycolipid stmc-ture (Ma et al. 2000). An optimized vesicle assembly, consisting of a maltotriosyl lipid, phospholipid, and diyne, detected E. coli at a concentration of 2x10 cells/mL... 

Temperature Ihe temperature in a bioreactor is an important parameter in any bioprocess, because all microorganisms and enzymes have an optimal temperature at which they function most efficiently. For example, optimal temperature for cell growth is 37 °C for Escherichia coli and 30 °C for Saccharomyces sp, respectively. Although there are many types of devices for temperature measurements, metal-resistance thermometers or thermistor thermometers are used most often for bioprocess instrumentation. The data of temperature is sufficiently reliable and mainly used for the temperature control of bioreactors and for the estimation of the heat generation in a large-scale aerobic fermentor such as in yeast production or in industrial beer fermentation. 

Cabilly, S. (1989) Growth at sub-optimal temperatures allows the production of functional, antigen-binding Fab fragments in Escherichia coli. Gene 85,553—557. 

G. Hannig and S. C. Makrides, Strategies for optimizing heterologous protein expression in Escherichia coli, Tiptech 1998, 16, 54-60. 

M. J. Weickert, D. H. Doherty, E. A. Best,and P. Q. Olins, Optimization of heterologous protein production in Escherichia coli, Curr. Opin. Biotechnol. 1996, 7(5), 494—499. 

Fed-batch production of pyruvic acid [CH3COCOOH] from an engineered strain (Escherichia coli YYC202) was optimized by resorting to ED to prevent potential product inhibition in the bioreactor (Zelic et al., 2004). In this way, by continuous separation of pyruvate from the fermentation medium, high values of the pyruvate-to-glucose molar yield (1.78 mol/mol), volumetric productivity (145 kg m 3day ), and pyruvate concentration (79 kg/m3) were achieved by the repeated fed-batch mode. 

Protein expression and purification have traditionally been time-consuming, case-specific endeavors, and are considered to be the greatest bottlenecks in most proteomics pipelines (1) Escherichia coli (E. coli) is the most convenient and cost-effective host, although optimal conditions for the expression of different proteins vary widely. Proteins vary in their structural stability, solubility, and toxicity in this environment, resulting in differing rates of protein degradation,... 

Varma, A. Palsson, B. O. Metabolic capabilities of Escherichia coli. 2. Optimal-growth patterns. J Theor Biol 1993, 165 503-522. 

Daugherty, P. S., Olsen, M.J., Iverson, B. L., and Georgiou, G. (1999). Development of an optimized expression system for the screening of antibody libraries displayed on the Escherichia coli surface. Protein Eng., 12(7), 613-621. 

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