Skip to main content

Advertisement

Table 2 Results for cell growth (measured by absorbance at 600 nm and converted to g (dry cell)/L) of E. coli BL21 (DE3) Star/pAE/LigB (131-645aa), yield (mg/L) and productivity ((mg/L)/h) of soluble recombinant LigB (131-645aa) expressed in shaking flasks at 28°C for 4 h in TB using central composite design for two variables (Abs ind and IPTG for induction) with triplicate at the central point (CP)

From: Evaluation of pre-induction temperature, cell growth at induction and IPTG concentration on the expression of a leptospiral protein in E. coli using shaking flasks and microbioreactor

   Induction conditions Cell growth (4 h ind) Soluble LigB expression (4 h ind)   
Assays Total process time (h)a Absind(x1) IPTG (x2) Abs600nm Dry cell (g/L) Model (g/L)b Yield (mg/L) Model (mg/L)b Productivity (mg/L)/h Model ((mg/L)/h)b pH Residual glucose (g/L)
1 5.75 0.75 (-1) 0.1 mM (-1) 3.75 0.9 0.94 (-4.4%) 180 177 (2%) 31.3 31.2 (0.4%) 6.64 6.4
2 5.83 0.75 (-1) 1.0 mM (+1) 3.31 0.8 0.74 (7.5%) 166 163 (2%) 28.4 28.4 (0.1%) 6.75 6.8
3 6.75 2.0 (+1) 0.1 mM (-1) 6.33 1.6 1.54 (3.8%) 288 286 (1%) 42.7 42.6 (0.2%) 6.36 5.2
4 7.00 2.0 (+1) 1.0 mM (+1) 5.19 1.3 1.34 (-3.1%) 221 218 (1%) 31.5 31.4 (0.5%) 6.24 5.1
CP 1c 6.25 1.4 (0) 0.55 mM (0) 4.83 1.2 1.14 (5.0%) 198 211 (-7%) 31.7 33.4 (-5.4%) 6.63 6.4
CP 2 6.25 1.4 (0) 0.55 mM (0) 4.46 1.1 1.14 (-3.6%) 214 211 (1%) 34.2 33.4 (2.4%) 6.53 5.8
CP 3 6.25 1.4 (0) 0.55 mM (0) 4.53 1.1 1.14 (-3.6%) 210 211 (-1%) 33.6 33.4 (0.6%) 6.55 5.1
  1. aTotal process time = growth time + 4 h induction. The growth time varied according to the time each culture took to reach the Absind required for the addition of IPTG and induction of LigB (131-645aa).
  2. bModel response obtained for each variable with its relative error in parenthesis (% = ((experimental data - predicted by model)/experimental data) x 100).
  3. cCP is the central point, calculated as the intermediate condition between the inferior (-1) and superior levels (+1) and coded as 0, according to experimental design procedures.
  4. The calculated errors were lower than 12%.