Glucose limitation

A bacterium was grown as a glucose-limited chemostat culture and steady state growth yield (Yx/J was measured at different dilution rates. 

Glucose limits sucdnoglycan production (ammonia limits growth). It is necessary to limit sucdnoglycan production to avoid an excessively viscous fermentation liquor which would affect mixing and subsequent downstream processing to recover exopolysaccharide. 

Thomas, T. D., Ellwood, D. C. and Longyear, V. M. C. 1979. Change from homo-to hetero-lactic fermentation by Streptococcus lactis resulting from glucose limitation in anaerobic chemostat cultures. J. BacterioL 138, 109-117. 

No Yes. Predictive alerts can be set to warn you 5, 10, 15, 20, 25, or 30 min before glucose limits have been reached. Rate of change alerts can be set to warn you when glucose levels are changing between 1.1 and 5 mg/dL/min, in 0.1 increments No... 

While this sensor was the first instance of a SWNT-based optical sensor and a step forward in nanotube applications, the sensor does have some disadvantages. First and foremost, the sensor would operate as an optical analogue of a flux-based sensor in any in vivo setting by using a glucose-limiting membrane and as such suffers from the same drawbacks of those sensors mentioned earlier. The sensor also has a limited lifetime, as the ferricyanide is a limited resource, and will eventually be used to completion. Finally, the sensor is not regenerable and would need to be completely replaced after its lifetime has been reached. 

Flayter PM, Curling EMA, Baines AJ., Jenkins N, Salmon I, Strange PG, Tong JM, Bull AT (1992), Glucose-limited chemostat culture of Chinese hamster ovary cells producing recombinant human interferon-. Biotechnol. Bioeng. 39 327-335. 

B. Gonzalez, A. de Graaf, M. Renaud and H. Sahm (2000). Dynamic in vivo 31P nuclear magnetic resonance study of Saccharomyces cerevisiae in glucose-limited chemostat culture during the aerobic-anaerobic shift. Yeast, 16, 483 -97. 

Figure 20-4. Biochemical pathways for gluconeogenesis in the liver. Alanine, a major gluconeogenic substrate, is used to synthesize oxaloacetate. The carbon skeletons of glutamine and other glucogenic amino acids feed into the TCA cycle as a-ketoglutarate, succinyl-CoA, fumarate, or oxaloacetate and thus also provide oxaloacetate. Conversion of oxaloacetate to phosphoenolpyruvate and ultimately to glucose limits the availability of oxaloacetate for citrate synthesis and thus greatly diminishes flux through the initial steps of the TCA cycle (dashed lines). Concurrent P-oxidation of fatty acids provides reducing equivalents (NADH and FADH2) for oxidative phosphorylation but results in accumulation of acetyl-CoA.

Fig. 4. Selection against the strain of E. coli carrying Tn 10 in the lactose operon in a glucose-limited chemostat.

E4P and PEP has been studied in much detail the extensive mutagenesis that has been applied to increase the bioavailability of these latter compounds has been reviewed [70-72]. It should be noted that the PTS, which mediates the uptake and phosphorylation of glucose, limits the yield of DAHP from glucose at 0.43 mol mol-1 in a situation that is similar to that described above in Section 8.2.4. If all PEP could be channeled into the aromatic pathway the stoichiometric yield of DAHP could be as high as 0.86 mol mol-1, at least in theory [73]. Various approaches to PEP conservation have been demonstrated [72, 74, 75]. 

Verduyn, C., Postma, E., Scheffers, W. A., van Dijken, J. P. (1990a) Physiology of Saccharomyces cerevisiae in anaerobic glucose-limited chemostat cultures. Journal of General Microbiology, 136, 395 03. 

Hayter PM, Curling EMA, Gould ML, Baines AJ, Jenkins N, Salmon I, Strange PG BuU AT (1993) The effect of the dilution rate on CHO cell physiology and recombinant interferon-7 production in glucose-limited chemostat culture. Biotechnology and Bioengineering 42 1077-1085. 

The influence of sudden oxygen depletion on Saccharomyces cerevisiae, grown in glucose limited chemostat culture, has been investigated with P NMR. During the switch from aerobic to anaerobic conditions there was a rapid, significant decrease in ATP, phosphoenolpyruvate (PEP) and intracel-... 

Guanosine triphosphate and ribulose-5-phosphate are recruited in a 1 2 stoichiometric ratio by GTP cyclohydrolase II and DHBP synthase, respectively, for riboflavin biosynthesis. Since at substrate saturation the activity of B. subtilis DHBP is twice the activity of B. suhtilis cyclohydrolase II (DSM, unpublished observations) and since both enzymatic activities are associated with the same bifunctional protein encoded by rihA, the balanced formation of the pyrimidinedione and the dihydroxybutanone intermediates is ensured. However, the ifg.s constant of DHBP synthase ( 1 mmol is about 100-fold higher than the ifg.s constant of GTP cyclohydrolase II imposing the risk of excessive synthesis of the pyrimidinone and pyrimidinedione intermediates in case of reduced intracellular concentrations of pentose phosphate pathway intermediates. This can be expected, for instance, in glucose-limited fed-batch fermentations, which are frequentiy used in industrial applications. The pyrimidinone and pyrimidinedione intermediates are highly reactive, oxidative compounds, which can do serious damage on the bacteria. 

Lin H Y, Mathiszik B, Xu B, Enfors S O, Neubauer P (2001). Determinantion of the maximum specific uptake capacities for glucose and oxygen in glucose-limited fed-batch cultivations of Escherichia coli. Biotechnol. Bioengin. 73 347-357. 

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