TABLE 1.
Characterization of E. coli D21g cells as a function of growth stage
| Growth stage | Growth time (h) | Ionic strength (M) | % Live cellsa | Cell radius (μm)b | MATH result (%)c | kRSPF,fav (m/s) | Acidity (meq/108 cell)d | Surfae charge (μC/cm2)e |
|---|---|---|---|---|---|---|---|---|
| Mid-exponential | 3 | 10−3 | 80 | |||||
| 3 | 10−2 | 80 | 0.87 | 16 ± 1 | 2.5 × 10−7 | 7.1 × 10−5 | 796.8 | |
| 3 | 10−1 | 77 | ||||||
| Stationary | 18 | 10−3 | 82 | |||||
| 18 | 10−2 | 86 | 0.93 | 34 ± 6 | 2.6 × 10−7 | 8.4 × 10−6 | 87.9 | |
| 18 | 10−1 | 73 |
Percentage of the cell population determined to be viable based on Live/Dead BacLight kit results.
Value for equivalent spherical radius calculated from the experimentally measured lengths and widths of individual cells. The average lengths and widths of the cells were 3.7 and 1.2 μm, respectively, for 3-h cells and 3.6 and 1.3 μm, respectively, for 18-h cells.
The microbial adhesion to hydrocarbons (MATH) test indicates the relative hydrophobicity of the cell as the percentage of cells partitioned into dodecane versus an electrolyte (10−2 M KCl).
Acidity was determined from the amount of NaOH consumed during a titration between pH 4 and 10 for cells suspended in 10−2 M KCl.
The surface charge indicates the density of charged functional groups across the cell surface. Values were determined from experimentally measured acidities, accounting for the exposed surface area of the cells (calculated for a spherical cell) and using the Faraday constant of 96,485 C/mol.