Kinetics of bacterial growth

The growth of bacteria contained in a nutrient medium has been studied very extensively, and a number of kinetic aspects are of particular interest. Only a brief account can be given here. 

An initial phase during which there is no cell division, so that the number of cells remains constant. This is known as the lag phase. 

A subsequent phase during which the logarithm of the number of cells varies linearly with time, which means that the number is increasing exponentially see below). This is known as the exponential or logarithmic phase. 

The stationary phase, during which there is no cell division. 

A typical bacterial growth cycle for cells growing in a closed system. 

---

Contois DE (1959), Kinetics of bacterial growth relationship between population density and specific growth rate of continuous cultures, J. Gen. Microbiol. 21 40-50. 

When the war was over most of the chemists returned to their pre-war interests, but some embarked on new ventures - Linnett in problems of molecular structure (although retaining his war-time interest in flames and combustion). Woodward in Raman spectroscopy, and Staveley in thermodynamics that he had studied before the War with Klaus Clusius in Munich but had not yet been able to follow up. Hinshelwood published some of the previously classified papers and continued work on the reactions on charcoal surfaces and other kinetic studies, but his heart was not in it as it had been earlier all that he was now really interested in was the kinetics of bacterial growth and adaptation. 

When microorganisms use an organic compound as a sole carbon source, their specific growth rate is a function of chemical concentration and can be described by the Monod kinetic equation. This equation includes a number of empirical constants that depend on the characteristics of the microbes, pH, temperature, and nutrients.54 Depending on the relationship between substrate concentration and rate of bacterial growth, the Monod equation can be reduced to forms in which the rate of degradation is zero order with substrate concentration and first order with cell concentration, or second order with concentration and cell concentration.144... 

A short report demonstrated the absence of a reliable correlation between kiUing kinetics and normal laboratory tests for pristinamycin susceptibility testing of some pneumococci (42). Eight selected multiresistant clinical isolates and two reference pristinamycin-resistant Streptococcus pneumoniae strains were studied. Disk diffusion susceptibility and MICs were determined by the agar dilution method, and all clinical isolates appeared to be susceptible to pristinamycin, whereas the two reference strains were not. In contrast, time-kill experiments identified a limited bactericidal effect of pristinamycin in three clinical and both reference strains. These three strains had been classified as pristinamycin-resistant by the Vitek-II system, which uses a kinetic turbidimetric measurement of bacterial growth. Epidemiological information is hindered by the use of highly selected strains for the study. 

Now this aloof style, avoiding the work of probably less able scientists, led Hinshelwood into a serious error in the new science he had chosen to enter just before the war. The error arose from his brave wish to carry over his chemical kinetic schemes into the analysis of rates of bacterial growth. Apart from doing some relatively simple experiments on this topic his group worked on the basic assumption, thoroughly sensible in chemistry, that your starting materials could be well-characterised chemically. This ignored the possibility of diversity and mutants in a population of cells. Despite the fact that the work led to a very... 

Nendza, M. and Seydel, J. K. (1990) Application of bacterial growth kinetics to in vitro toxicity assessment of substituted phenols and anilines. Ecotoxicol. Environ. Saf, 19, 228-41. 

In paper [10] the first mathematical model of the process was developed. It was based on single-phase flow model coupled with population dynamics equation. The bacterial population was considered in the average and various forms of its existence were reflected in nonlinear kinetics of population growth. 

Volkering, F., Breure, A. M., Sterkenburg, A. and van Andel, J. G. (1992). Microbial degradation of polycyclic aromatic hydrocarbons effect of substrate availability on bacterial growth kinetics, Appl. Microbiol. Biotechnol., 36, 548-552. 

CO2 = Cti + S2 — Z, (f = CO2 + KhPt + qcHi/kLa-, Pt is the total pressure within the digester and qcRi is the molar flow rate of methane. The bacterial growth rates for acetogenic (Ai) and methanogenic X2) bacteria are approached by the Monod and Haldane kinetics... 

Alice et al studied the turnover kinetics of Listeria OTonocytogenex-secreted p60 protein (a murein hydrolase) by host cell cytosolic proteasomes. J774 cells, seeded in flasks and incubated overnight in culture medium, were infected with log-phase cultures of E. monocytogenes for 30 min, washed, and incubated in culture medium for 3 h, with gentamicin (50 tg/ml) added after the first 30 min to inhibit extracellular bacterial growth. Cells then were washed and placed in methionine-free medium with spectinomycin, gentamicin, the eukaryotic protein synthesis inhibitors [cycloheximide (50 tg/mL) and anisomycin (30 tg/ml),] and 25 dVI calpain inhibitor I. After 30 min, [ S]methionine was added, and the cells were pulse-labeled for periods of 20 to 60 min. Cells... 

Monod kinetics are often a better description of the reactions occurring in sediment. Assume that the flux conditions are similar to problem 2 for SOD. The maximum bacterial growth rate is 0.5 hr in these sediments, and the halfsaturation coefficient is 1 g/m of oxygen. What is the microbacterial population for the 0.5- and 5-g/m -day cases (Hint, use a change of variables to solve for / = dCIdz.) Plot oxygen concentration for each case on the same scale as for problem 2 and compare the two plots. 

For example, Schmidt et al. (1985) developed 12 kinetic models for the metabolism of organic chemicals that are not supporting bacterial growth. Assignment of the appropriate kinetic model requires measurement of sufficient experimental points on the disappearance curve. Often insufficient data points are collected to assign a kinetic model, especially with screening studies. Temperature definitely has an impact on the biodegradation kinet- 2000 CRC Press LLC... 

A weakness of the model discussed above is its reliance on detailed information about C N ratios of bacterial substrates that is currently unavailable. A later study modeled bacterial growth by optimizing electron flow, substrate uptake kinetics, and bacterial C N ratio (VaUino et al., 1996). This study found that the C Ns ratio is not always an accurate predictor of whether bacteria wiU remineralize NH4. ... 

Where might this be important As discussed above, biological activity can result in the simultaneous precipitation of mixtures of nanoscale sulfide minerals under certain conditions. Each mineral will exhibit a particular particle size distribution, dependent on the solution composition, bacterial activity, rate of crystal growth, and the nature of electrochemical interactions between the particles. These electrochemical reactions could lead to oxidation of one type of nanophase sulfide mineral of a certain size, and reduction of another type of nanophase sulfide particle or other species in the solution. In this way, a tremendous number of mineral-solution-mineral galvanic cells could develop, with potentially significant impact on dissolution kinetics, growth kinetics, and the mixture of phases observed. In addition to environmental relevance, these processes may shape the mineralogy of low-temperature ore deposits. 

So is the constant concentration of growth substrate that is added at flow rate D to the chemostat. S and B are the concentrations of growth substrate and bacteria in the chemostat, respectively. K is the Monod constant, which is formally identical to the Michaelis constant of enzyme kinetics, p is the maximal growth rate constant, and Y is the amount of bacterial cells produced from a given amount of substrate (yield). 

Effect on bacterial growth kinetics J. K. Seydel, E. Wempa, Chemotherapy 26, 361 (1980). In vitro activity of tbe tetroxoprim-sulfadiazine combination H. Hahn, A. Kirov, Arzneimittel-Forsch. 30, 1047 (1980). 

This study aimed to select the best strain for bacterial cellulose (BC) production along with the investigation of the cell growth and substrate utilization. The kinetics of growth and... 

Physical chemistry too saw very few changes in personnel or in research topics until the closing years of Hinshelwood s time, 1960-65, which are treated in the next section. As described earlier, he continued his work in kinetics of gas reactions and bacterial growth. He had assistants, C.J. Danby (1945), A.R.C. Dean (1955) and B.A. Coles (1960) but he did not exert great pressure for new appointments especially after 1955. H.W. Thompson and L.E. Sutton, also mentioned earlier had been moved to the 1941 laboratory from inorganic chemistry and from organic chemistry, respectively, but their dates of... 

---