RI protein activities in kilo units per gram of wet cell weight [kU (gCWW)-1] after shake flask batch cultivation of E. coli ER2566 pET21bRI or with additional chaperone co-overexpression using the pKJE7 (DnaK/DnaJ/GrpE) or pGro7 ( GroELS) vectors at 22, 30 or 37°C in glucose-MSM without DTT (A) or with addition of DTT (B). Shake flask cultures were performed in glucose MSM at 37°C until an OD600 of 1 to 1.5. Chaperons were induced with 0.4 g L-1 of arabinose 2 hours before RI induction (0.2 mM IPTG) at 37°C. The temperature was set at the time of RI induction to 22, 30 or 37°C, respectively. DTT (12 mM final concentration) was added at the time of RI induction (triangles) or 2 hours later (squares). Samples were collected 4 hours after RI induction. Standard deviations represent 2 independent cultivations and 3 assays.