Figure 7

Comparison of the oxygen transfer rate (OTR), pH and glycerol concentration during the cultivation of E. coli K12 in buffered or pH-controlled media using controlled-release discs in shaking flasks. a: without buffer, b: with 0.2 M MOPS buffer, c: without buffer and additional 3 controlled release discs, d: without buffer and additional 4 controlled-release discs. OTR (■); pH (▲); glycerol concentration (○); OD₆₀₀ (♦); Experimental conditions: Wilms-MOPS medium with 20 g/L glycerol, 37°C; 10 mL filling volume; shaking diameter (d₀) 50 mm; 350 rpm; OD_600,α = 0.5; pH₀ = 7; controlled-release discs: D = 15 mm; H = 1.1 mm; 30% (w/w) Na₂CO₃, washed for 30 min in H₂O.