# Q10 (temperature coefficient) for growth of E. coli B/r (21-37°C)

Value 2 Unitless Bacteria Escherichia coli Calculated visually from figure 1 in John L. Ingraham and Allen G. Marr, Effect of Temperature, Pressure, pH, and Osmotic Stress on Growth, chapter 98, Neidhardt, et al. eds. Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd ed. Herendeen SL, VanBogelen RA, Neidhardt FC. Levels of major proteins of Escherichia coli during growth at different temperatures. J Bacteriol. 1979 Jul139(1):185-94.PubMed ID156716 Calculated by visually measuring growth rates (k) on glucose minimal medium at 37°C and 23°C according to equation Q10=[k37°/k23°]^[10/(37-23)]=[1/0.38]^[10/14]=1.996. Note: As can be seen in figure, this value is constant in the temp range of 21°C-37°C. The value is the same in rich medium. Measurement method of primary source: The adaptation of Escherichia coli B/r to temperature was studied by measuring the levels of 133 proteins (comprising 70% of the cell's protein mass) during balanced growth in rich medium at seven temperatures from 13.5 to 46 degrees C. The growth rate of this strain in either rich or minimal medium varies as a simple function of temperature with an Arrhenius constant of approximately 13,500 cal (ca. 56,500 J) per mol from 23 to 37 degrees C, the so-called normal range above and below this range the growth rate decreases sharply. The Arrhenius relationship between the velocity (v) of chemical reactions and absolute temperature (T), v = e^–(AE* / RT) (E* is the energy of the reaction, R is the universal gas constant, and A is a constant called the collision or the frequency factor), predicts a straight-line relationship between the logarithm of velocity and the reciprocal of absolute temperature which holds for most simple chemical reactions. When applied to the specific growth rate, k, of bacteria as a function temperature (for this application the term µ, the temperature characteristic, is substituted for AE*), the form of the plot is similar for almost all bacteria. Over a certain interval of temperature, commonly called the normal range, log k is linear with 1/T. At higher and lower temperatures, the growth rate decreases progressively, approaching a vertical asymptote at both the maximum and minimum temperatures for growth. Most bacteria, including E. coli and S. typhimurium, can grow over a range of approximately 40°C. The growth rates of most wild-type strains of E. coli and S. typhimurium respond similarly to changes in temperature the particular response of E. coli B/r is shown in Fig. 1. The normal temperature range extends from 21 to 37°C, over which range µ has a value of 13,000 to 14,000 cal/mol (ca. 54,000 to 59,000 J/mol, BNID 105004). The maximum temperature at which balanced growth can be sustained by this strain is approximately 49°C (BNID 105002). The minimum temperature for sustained growth of E. coli ML30, and presumably other strains as well, lies between 7.5 and 7.8°C (Shaw et al 1971, PMID 4925195 BNID 105003). Uri M 105005