Scientist Solutions - antibiotic production

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BETH HELENE JUNKER. Scale-Up Methodologies for Escherichia coli and Yeast Fermentation Processes. J. BIOSCI. BIOENG., Vol. 97, 347-364 (2004) .

Abstract:
Scale-up techniques from the literature have been compiled and reviewed for applicability to Escherichia coli and yeast processes. The consistency of design and operating parameters for the pilot scale vessels in an existing fermentation pilot plant, ranging in nominal volume from 100 l to 19,000 l, was established and compared favorably with approaches found in the literature. Differences were noted as a function of parameters such as fermentor scale, vessel geometry, agitator type/size and ungassed/gassed power input. Further analysis was conducted using actual fermentation data for historical and recent development processes collected over a 10-year-period, focussing on operating conditions at peak culture oxygen uptake rates. Scale-up estimates were performed based on geometric similarity, agitator tip speed, gassed power per unit volume and mixing time. Generally, scale-up calculations from the 280 l scale were most similar to the parameters of installed equipment. Scale-up from the 30 l laboratory scale typically underpredicted parameters with scale-up from the 280 l scale being most appropriate. The 19,000 l fermentor installation was notably different in geometric similarity from the 280 l1900 l scales since its design was meant to accommodate a wide range of operating volumes. Analysis of historical and recent processing performance was conducted for single cell bacterial or yeast fermentations which challenged peak operating conditions of the fermentors. Identification of key issues associated with scale-up for these specific pilot plant vessels was believed to be critical to efficient process development, clinical material production, and expected process transfer to a manufacturing facility.

F. Bylund, A. Castan, R. Mikkola, A. Veide, G. Larsson. Influence of scale-up on the quality of recombinant human growth hormone. 2000. Volume 69, Issue 2 , Pages 119 128.

Abstract:
The aerobic fed-batch production of recombinant human growth hormone (rhGH) by Escherichia coli was studied. The goal was to determine the production and protein degradation pattern of this product during fed-batch cultivation and to what extent scale differences depend on the presence of a fed-batch glucose feed zone. Results of laboratory bench-scale, scale-down (SDR), and industrial pilot-scale (3-m3) reactor production were compared. In addition to the parameters of product yield and quality, also cell yield, respiration, overflow, mixed acid fermentation, glucose concentration, and cell lysis were studied and compared. The results show that oxygen limitation following glucose overflow was the critical parameter and not the glucose overflow itself. This was verified by the pattern of byproduct formation where formate was the dominating factor and not acetic acid. A correlation between the accumulation of formate, the degree of heterogeneity, and cell lysis was also visualized when recombinant protein was expressed. The production pattern could be mimicked in the SDR reactor for all parameters, except for product quantity and quality, where 30% fewer rhGH-degraded forms were present and where about 80% higher total yield was achieved, resulting in 10% greater accumulation of properly formed rhGH monomer. 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 69: 119-128, 2000

Behal, V.
The tetracycline fermentation and its regulation.
CRC CRIT. REV. BIOTECHNOL. Vol. 5, no. 4, pp. 275-318. 1987.

Abstract:
Production of tetracyclines materializes at the conditions of growth limitation of producing microorganism. After attaining a limit the activity of primary metabolism decreases and enzymes of secondary metabolism are induced. Enzymes of secondary metabolism polymerizing malonylCoA and transforming the pretetramid formed are apparently organized in a multienzyme complex. The production of tetracycline is determined by the amount of these enzymes.

Shang-Shyng Yang, Meei-Yueh Ling. Tetracycline production with sweet potato residue by solid state fermentation. Biotechnology and Bioengineering. 2004. Volume 33, Issue 8 , Pages 1021 1028

Abstract:
For saving energy in antibiotic production and reducing the amount of agricultural wastes, solid state fermentation was used in this study to produce tetracycline with sweet potato residue by Streptomyces viridifaciens ATCC 11989. It was found that the optimal media for tetracycline production were sweet potato residue 100 g, organic nitrogen (rice bran, wheat bran, or peanut meal) 20 g, (NH4)2SO4 2.4 g, KH2PO4 0.4 g, CaCO3 1.8 g, NaCl 0.6 g, MgCl2 0.8 g, soluble starch 10 g, methionine 0.2 g, histidine 0.8 g, and monosodium glutamate 1.6 g with initial moisture content 68-72%, and initial pH 5.8-6.0. Each gram of dry weight substrate was inoculated with 1.0 × 108 conidia and incubated at 26°C for 5-7 days, producing 4720 g of total tetracycline equivalent potency. When incubated at 26°C with the initial moisture content 68%, the conidia in solid media germinated on the second day, mycelia grew abundantly on the third day and reached stationary phase on the sixth day. The antibiotic production was consistent with the morphogenesis of S. viridifaciens: activity could be detected on the third day, had the maximal potency on the sixth day, and decreased slightly on the tenth day. (11-3-88 tly).

Jullian Jones, Tarangsri Nivitchanyong, Christina Giblin, Valentina Ciccarone, David Judd, Stephen Gorfien, Sharon S. Krag, Michael J. Betenbaugh. Optimization of tetracycline-responsive recombinant protein production and effect on cell growth and ER stress in mammalian cells. 2005. Volume 91, Issue 6 , Pages 722 - 732

Abstract:
The inducible T-REx system and other inducible expression systems have been developed in order to control the expression levels of recombinant protein in mammalian cells. In order to study the effects of heterologous protein expression on mammalian host behavior, the gene for recombinant Human transferrin (hTf) was integrated into HEK-293 cells and expressed under the control of the T-REx inducible technology (293-TetR-Hyg-hTf) or using a constitutive promoter (293-CMV-hTf). A number of inducible clones with variable expression levels were identified for the T-REx system with levels of hTf for the high expressing clones nearly double those obtained using the constitutive cytomegalovirus (CMV) promoter. The level of transferrin produced was found to increase proportionately with tetracycline concentration between 0 and 1 g/mL with no significant increases in transferrin production above 1 g/mL. As a result, the optimal induction time and tetracycline concentrations were determined to be the day of plating and 1 g/mL, respectively. Interestingly, the cells induced to express transferrin, 293-TetR-Hyg-hTf, exhibited lower viable cell densities and percent viabilities than the uninduced cultures for multiple clonal isolates. In addition, the induction of transferrin expression was found to cause an increase in the expression of the ER-stress gene, BiP, that was not observed in the uninduced cells. However, both uninduced and induced cell lines containing the hTf gene exhibited longer survival in culture than the control cells, possibly as a result of the positive effects of hTf on cell survival. Taken together, these results suggest that the high level expression of complex proteins in mammalian cells can limit the viable cell densities of cells in culture as a result of cellular stresses caused by generating proteins that may be difficult to fold or are otherwise toxic to cells. The application of inducible systems such as the T-REx technology will allow us to optimize protein production while limiting the negative effects that result from these cellular stresses. 2005 Wiley Periodicals, Inc.