Ammonium growth rate

Combining ammonium immobilization rates with estimates of C inputs and C maintenance requirement (proportional to the active microbial biomass), whose difference gave C available for microbial growth from the same experimental system (111,128), it allowed the building up of a conceptual model for C and N... 

Typical kinetic profiles (hybridoma). (A) Cell concentration and viability (B) glucose consumption (GLC) and lactate production (LAC) (C) monoclonal antibody production (mAb) (D) glutamine consumption (GLN) and ammonium production (NH4+) (E) specific growth rate (px) (F) alanine (ALA) and glycine (GLY) production. Adapted from Lee (2003). Symbols correspond to the experimental data and the lines to the manual curve fitting. Vertical lines indicate the instant at which exponential growth phase ended (gx < Px.max)-... 

The first three columns of Table 10.5 show sieve data for a 100-cc slurry sample containing 21.0 g of solids taken from a 20,000-gal (75-m3) mixed suspension-mixed product removal crystallizer (MSMPR) producing cubic ammonium sulfate crystals. Solids density is 1.77 g/cm3, and the density of the clear liquor leaving the crystallizer is 1.18 g/cm3. The hot feed flows to the crystallizer at 374,000 lb/h (47 kg/s). Calculate the residence time r, the crystal size distribution function n, the growth rate G, the nucleation density n°, the nucleation birth rate B°, and the area-weighted average crystal size L3 2 for the product crystals. 

Dortch, Q., Thompson, P. A., and Harrison, P. J. (1991a). Short-term interaction between nitrate and ammonium uptake in Thalassiosira pseudonana Effect of preconditioning nitrogen source and growth rate. Mar. Biol. 110, 183—193. 

Uptake capacity is dependent on the number and eiEciency of membrane transport proteins. It is not really known how the numbers of transporters (e.g. ammonium or nitrate) per cell varies as a function of physiological state, or how the kinetics of transport may be a function of the protein structure of the transporters themselves. Some studies indicate that the number of transporters per cell increase with nitrogen limitation, but kinetic data suggests otherwise and that transporter numbers are more or less constant as a function of growth rate under N limitation... 

Dortch, Q., and Conway, H. L. (1984). Interactions between nitrate and ammonium uptake— variation with growth-rate, nitrogen-source and species. Mar. Biol. 79, 151-164. 

Takubo, H. Kume, S. Koizumi, M. Relationship between supersaturation, solution velocity, crystal habit and growth rate in crystallization of ammonium phosphate (NH4H2PO4). J. Cryst. Growth 1984, 67 (2), 217-226. 

Finally, cell-quota theory treats the entire cellular content of a nutrient as being the pool controlling growth rate (under limiting conditions), and deals with multiple nutrient interactions empirically. At the third level of description, MECHANISTIC models aim to embody realistic accounts of the main biochemical processes and pools within cells. A recent example (Flynn Hipkin, 1999 Flynn, 2001) deals with nitrogen, phosphorus, silicon and iron as well as the carbon content of cells, photosynthesis, and the uptake competition between ammonium and nitrate. However, the model embodies many parameters and there is currently insufficient information to use it to distinguish between groups or species of phytoplankters. Its characteristic nutrient quota parameters are included in Table 9.3 except for those for silicon, which are cell-based. 

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