Figure 6

Influence of different initial pH-values and buffer concentrations on the Oxygen transfer rate (OTR) in E. coli K12 cultures in Wilms-MOPS medium using glycerol as carbon source and with and without controlled-release discs. With 0.2 M MOPS buffer, initial pH 7 (■), 0.2 M MOPS buffer, initial pH 7.5 (◇), with 0.1 M MOPS buffer, initial pH 7 and 3 controlled-release discs (●), with 0.1 M MOPS buffer; initial pH 7.5 and 3 controlled-release discs (Δ). 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; controlled-release discs: D = 15 mm; H = 1.1 mm; 30% (w/w) Na₂CO₃, washed for 30 min in H₂O.